Publications by authors named "Yuchen Deng"

29 Publications

  • Page 1 of 1

Regulating coordination number in atomically dispersed Pt species on defect-rich graphene for n-butane dehydrogenation reaction.

Nat Commun 2021 May 11;12(1):2664. Epub 2021 May 11.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, and BIC-ESAT, Peking University, Beijing, P. R. China.

Metal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure-performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction.
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http://dx.doi.org/10.1038/s41467-021-22948-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8113322PMC
May 2021

Color-Tunable Aqueous Room-Temperature Phosphorescence Supramolecular Assembly.

ACS Appl Mater Interfaces 2021 Mar 22;13(12):14407-14416. Epub 2021 Mar 22.

National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin 300130, P. R. China.

Developing room-temperature phosphorescence (RTP) materials with color-tunability performance in an aqueous environment is crucial for application in optoelectronic areas to a higher stage, such as multicolor display, visual detection of external stimulus, and high-level information anticounterfeiting, but still faces a formidable challenge. Herein, we propose an efficient design strategy to develop excitation wavelength-responsive RTP supramolecular co-assembly systems of a simple benzoic acid derivative and Laponite () clay nanoplates in aqueous solution, displaying an ultralong lifetime (0.632 s) and a high phosphorescence quantum efficiency (18.04%) simultaneously. Experimental and theoretical research studies suggest that this distinctive feature is due to the generation of more and efficient intersystem crossing pathways benefiting from the coexistence of isolated and J-aggregation states via controlling the doping of the benzoic acid derivative and the inhibition of phosphorescence quenching by water because of the synergistic effects of robust hydrogen-bonding interactions between and the benzoic acid derivative, J-aggregations of the benzoic acid derivative, and good oxygen tolerance of the clay. By virtue of their excellent RTP performances in aqueous solution, the visual colorimetric detection of Ag in a water environment was achieved for the first time, and visible and high-level information encryption was accomplished as well.
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http://dx.doi.org/10.1021/acsami.1c01174DOI Listing
March 2021

Tunable Covalent Organic Frameworks with Different Heterocyclic Nitrogen Locations for Efficient Cr(VI) Reduction, Disinfection, and Paracetamol Degradation under Visible-Light Irradiation.

Environ Sci Technol 2021 04 19;55(8):5371-5381. Epub 2021 Mar 19.

College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.

Covalent organic frameworks (COFs) have great application potentials in photocatalytic water treatment. By using -phenylenediamine with different numbers and locations of heterocyclic nitrogen atoms as a precursor, five types of COFs with different nitrogen positions were synthesized. We found that Cr(VI) photoreduction, inactivation, and paracetamol degradation by COFs were heterocyclic nitrogen location-dependent. Particularly, the photocatalytic performance for all three tested pollutants by five types of COFs followed the order of the best performance for COF-PDZ with two ortho position heterocyclic N atoms, medium for COF-PMD with two meta position heterocyclic N atoms, and COF-PZ with two para position heterocyclic N atoms, and COF-PD with a single heterocyclic N atom, the worst performance for COF-1 without a heterocyclic N atom. Compared to the other COFs, COF-PDZ contained improved quantum efficiency and thus enhanced generation of electrons. The lower energy barriers and larger energy gaps of COF-PDZ contributed to its improved quantum efficiencies. The stronger affinity to Cr(VI) with lower adsorption energy of COF-PDZ also contributed to its excellent Cr(VI) reduction performance. By transferring into a more stable keto form, COF-PDZ showed great stability through five regeneration and reuse cycles. Overall, this study provided an insight into the synthesis of high-performance structure-dependent COF-based photocatalysts.
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http://dx.doi.org/10.1021/acs.est.0c07857DOI Listing
April 2021

A stable low-temperature H-production catalyst by crowding Pt on α-MoC.

Nature 2021 01 20;589(7842):396-401. Epub 2021 Jan 20.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, and BIC-ESAT, Peking University, Beijing, China.

The water-gas shift (WGS) reaction is an industrially important source of pure hydrogen (H) at the expense of carbon monoxide and water. This reaction is of interest for fuel-cell applications, but requires WGS catalysts that are durable and highly active at low temperatures. Here we demonstrate that the structure (Pt-Pt)/α-MoC, where isolated platinum atoms (Pt) and subnanometre platinum clusters (Pt) are stabilized on α-molybdenum carbide (α-MoC), catalyses the WGS reaction even at 313 kelvin, with a hydrogen-production pathway involving direct carbon monoxide dissociation identified. We find that it is critical to crowd the α-MoC surface with Pt and Pt species, which prevents oxidation of the support that would cause catalyst deactivation, as seen with gold/α-MoC (ref. ), and gives our system high stability and a high metal-normalized turnover number of 4,300,000 moles of hydrogen per mole of platinum. We anticipate that the strategy demonstrated here will be pivotal for the design of highly active and stable catalysts for effective activation of important molecules such as water and carbon monoxide for energy production.
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http://dx.doi.org/10.1038/s41586-020-03130-6DOI Listing
January 2021

Maximizing the Synergistic Effect of CoNi Catalyst on α-MoC for Robust Hydrogen Production.

J Am Chem Soc 2021 Jan 31;143(2):628-633. Epub 2020 Dec 31.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, College of Engineering and BIC-ESAT, Peking University, Beijing 100871, China.

We report the syntheses of highly dispersed CoNi bimetallic catalysts on the surface of α-MoC based on the strong metal support interaction (SMSI) effect. The interaction between the nearly atomically dispersed Co and Ni atoms was observed for the first time by the real-space chemical mapping at the atomic level. Combined with the ability of α-MoC to split water at low temperatures, the as-synthesized CoNi/α-MoC catalysts exhibited robust and synergistic performance for the hydrogen production from hydrolysis of ammonia borane. The metal-normalized activity of the bimetallic 1.5Co1.5Ni/α-MoC catalyst reached 321.1 mol·mol·min at 298 K, which surpasses all the noble metal-free catalysts ever reported and is four times higher than that of the commercial Pt/C catalyst.
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http://dx.doi.org/10.1021/jacs.0c11285DOI Listing
January 2021

Inverse ZrO/Cu as a highly efficient methanol synthesis catalyst from CO hydrogenation.

Nat Commun 2020 Nov 13;11(1):5767. Epub 2020 Nov 13.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering and BIC-ESAT Peking University, Beijing, 100871, China.

Enhancing the intrinsic activity and space time yield of Cu based heterogeneous methanol synthesis catalysts through CO hydrogenation is one of the major topics in CO conversion into value-added liquid fuels and chemicals. Here we report inverse ZrO/Cu catalysts with a tunable Zr/Cu ratio have been prepared via an oxalate co-precipitation method, showing excellent performance for CO hydrogenation to methanol. Under optimal condition, the catalyst composed by 10% of ZrO supported over 90% of Cu exhibits the highest mass-specific methanol formation rate of 524 gkgh at 220 °C, 3.3 times higher than the activity of traditional Cu/ZrO catalysts (159 gkgh). In situ XRD-PDF, XAFS and AP-XPS structural studies reveal that the inverse ZrO/Cu catalysts are composed of islands of partially reduced 1-2 nm amorphous ZrO supported over metallic Cu particles. The ZrO islands are highly active for the CO activation. Meanwhile, an intermediate of formate adsorbed on the Cu at 1350 cm is discovered by the in situ DRIFTS. This formate intermediate exhibits fast hydrogenation conversion to methoxy. The activation of CO and hydrogenation of all the surface oxygenate intermediates are significantly accelerated over the inverse ZrO/Cu configuration, accounting for the excellent methanol formation activity observed.
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http://dx.doi.org/10.1038/s41467-020-19634-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7666171PMC
November 2020

Impacts of age, diabetes, gender, and access type on costs associated with vascular access among Chinese patients on hemodialysis.

Int J Artif Organs 2021 May 4;44(5):302-309. Epub 2020 Oct 4.

Kidney Research Laboratory, Division of Nephrology, West China Hospital of Sichuan University, Chengdu, China.

Objectives: Examine the impacts of age, diabetes, gender, and access type on vascular access (VA) associated costs among Chinese hemodialysis (HD) patients.

Methods: We retrospectively included patients whose first permanent VA was created at the West China Hospital. Clinical characteristics, maturation, intervention, utilization, and exchange of every VA, as well as VA-related infection were collected. The study period for each patient was from HD initiation to the last follow-up. VA-related costs, including those for placement and intervention procedures, were calculated according to the standards set in 2019 for Chinese tertiary hospitals. U and Chi-square tests were conducted for comparisons between groups.

Results: A total of 358 Chinese HD patients experienced functionally 143 arteriovenous fistula (AVF), 22 arteriovenous graft (AVG), and 439 tunneled cuffed central venous catheter (tcCVC) during a median study period of 26 (IQR 13-44) months, of which 42.5% used more than one permanent VA. The median annual VA-related cost in the groups of age >75 years and ⩽75 years, diabetes and non-diabetes, male and female, was $525 and $397 ( = 0.016), $459 and $462 ( = 0.64), $476 and $445 ( = 0.94), respectively. The median monthly costs for AVF ($18), AVG ($289), and tcCVC ($37) were significantly different.

Conclusion: HD patients aged >75 years had significantly higher annual VA-related costs. However, the annual VA-related costs did not differ across the diabetes groups or the gender groups. AVF was the most cost-effective permanent VA type in China, partly due to the inexpensive materials used compared to AVG or tcCVC.
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http://dx.doi.org/10.1177/0391398820962112DOI Listing
May 2021

Electron-event representation data enable efficient cryoEM file storage with full preservation of spatial and temporal resolution.

IUCrJ 2020 Sep 7;7(Pt 5):860-869. Epub 2020 Aug 7.

Molecular Medicine Program, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada.

Direct detector device (DDD) cameras have revolutionized electron cryomicroscopy (cryoEM) with their high detective quantum efficiency (DQE) and output of movie data. A high ratio of camera frame rate (frames per second) to camera exposure rate (electrons per pixel per second) allows electron counting, which further improves the DQE and enables the recording of super-resolution information. Movie output also allows the correction of specimen movement and compensation for radiation damage. However, these movies come at the cost of producing large volumes of data. It is common practice to sum groups of successive camera frames to reduce the final frame rate, and therefore the file size, to one suitable for storage and image processing. This reduction in the temporal resolution of the camera requires decisions to be made during data acquisition that may result in the loss of information that could have been advantageous during image analysis. Here, experimental analysis of a new electron-event representation (EER) data format for electron-counting DDD movies is presented, which is enabled by new hardware developed by Thermo Fisher Scientific for their Falcon DDD cameras. This format enables the recording of DDD movies at the raw camera frame rate without sacrificing either spatial or temporal resolution. Experimental data demonstrate that the method retains super-resolution information and allows the correction of specimen movement at the physical frame rate of the camera while maintaining manageable file sizes. The EER format will enable the development of new methods that can utilize the full spatial and temporal resolution of DDD cameras.
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http://dx.doi.org/10.1107/S205225252000929XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7467176PMC
September 2020

Highly Selective Olefin Production from CO Hydrogenation on Iron Catalysts: A Subtle Synergy between Manganese and Sodium Additives.

Angew Chem Int Ed Engl 2020 Nov 24;59(48):21736-21744. Epub 2020 Sep 24.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, and BIC-ESAT, Peking University, Beijing, 100871, P. R. China.

Mn and Na additives have been widely studied to improve the efficiency of CO hydrogenation to valuable olefins on Fe catalysts, but their effects on the catalytic properties and mechanism are still under vigorous debate. This study shows that Fe-based catalysts with moderate Mn and Na contents are highly selective for CO hydrogenation to olefins, together with low selectivities for both CO and CH and much improved space-time olefin yields compared to state-of-the-art catalysts. Combined kinetic assessment and quasi in situ characterizations further unveil that the sole presence of Mn suppresses the activity of Fe catalysts because of the close contact between Fe and Mn, whereas the introduction of Na mediates the Fe-Mn interaction and provides strong basic sites. This subtle synergy between Na and Mn sheds light on the importance of the interplay of multiple additives that could bring an enabling strategy to improve catalytic activity and selectivity.
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http://dx.doi.org/10.1002/anie.202009620DOI Listing
November 2020

The role of echocardiography in prognosis for dysfunction and abandonment of radiocephalic arteriovenous fistula in elderly Chinese patients on hemodialysis.

Semin Dial 2020 07 22;33(4):309-315. Epub 2020 Mar 22.

Kidney Research Laboratory, Division of Nephrology, West China Hospital of Sichuan University, Chengdu, China.

The objective of this study was to examine the impact of cardiac structure and function at baseline on the outcomes associated with arteriovenous fistula (AVF) in patients on hemodialysis (HD). Patients who initiated HD aged ≥70 years and received a mature AVF creation were included retrospectively. Echocardiographic parameters measured within 1 week before AVF creation were acquired. The observational period for each patient was from the point of AVF creation to the last time of follow-up unless AVF abandonment or death occurred. Kaplan-Meier and Cox proportional hazard regression analyses were conducted. A total of 82 elderly Chinese HD patients with mature radiocephalic AVF (RCAVF) and EF ≥50% were analyzed. During the median study period of 26.8 (12-40) months, 42 (51.2%) experienced RCAVF dysfunction and 34 (41.5%) progressed to abandonment. Primary and cumulative patencies at 6, 12, 24, and 36 months were 81%, 73%, 48%, 38%, and 84%, 81%, 68%, 55%, respectively. Left ventricle end-diastolic volume (LVEDV) ≤103.5 mL (HR = 2.5, P = .019) and the right side of RCAVF (HR = 3.59, P = .003) significantly predicted RCAVF dysfunction. The main pulmonary artery internal diameter (MPAID) ≤21.5 mm (HR = 4.3, P = .001) as well as the right side (HR = 2.95, P = .047) were the independent predictors for RCAVF abandonment. In conclusion, LVEDV, MPAID assessed by echocardiography and the right side of RCAVF, showed significant predictive implications for the outcomes of RCAVF. Disparities among nationalities in the areas of utilization and patency of AVFs necessitate additional studies.
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http://dx.doi.org/10.1111/sdi.12871DOI Listing
July 2020

Proton-Activated Amorphous Room-Temperature Phosphorescence for Humidity Sensing and High-Level Data Encryption.

Chem Asian J 2020 Apr 5;15(7):1088-1093. Epub 2020 Mar 5.

National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization Tianjin Key Laboratory of Chemical Process Safety School of Chemical Engineering and Technology, Hebei University of Technology, GuangRong Dao 8, Hongqiao District, Tianjin, 300130, P. R. China.

Supramolecular co-assembling terpyridine-derivatives with nanoclay (LP) are exploited to acquire efficient amorphous room-temperature phosphorescence (RTP). Experimental and theoretical investigations reveal that this co-assembly not only brings about a configuration transformation from the trans-trans (a) to the cis-trans (a'') form via the protonating process, significantly narrowing the singlet-triplet energy gap, thereby effectively facilitating the single-triplet ISC processes, but also well protects the triplet state and suppresses the nonradiative transitions via restricting molecular rotation and vibration by the hydrogen-bond interactions between them. Additionally, the flexible and transparent films, through co-assembling 1@LP (or 2@LP) with polyvinyl alcohol (PVA), also display excellent phosphorescence performance. Owing to their distinctive RTP performances, the RH sensing and high-level data encryption are achieved.
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http://dx.doi.org/10.1002/asia.201901747DOI Listing
April 2020

Low Temperature Oxidation of Ethane to Oxygenates by Oxygen over Iridium-Cluster Catalysts.

J Am Chem Soc 2019 Dec 28;141(48):18921-18925. Epub 2019 Oct 28.

Beijing National Laboratory for Molecular Engineering, College of Chemistry and Molecular Engineering and College of Engineering, BIC-ESAT , Peking University , Beijing 100871 , P. R. China.

Direct selective oxidation of light alkanes, such as ethane, into value-added chemical products under mild reaction conditions remains a challenge in both industry and academia. Herein, the iridium cluster and atomically dispersed iridium catalysts have been successfully fabricated using nanodiamond as support. The obtained iridium cluster catalyst shows remarkable performance for selective oxidation of ethane under oxygen at 100 °C, with an initial activity as high as 7.5 mol/mol/h and a selectivity to acetic acid higher than 70% after five in situ recycles. The presence of CO in the reaction feed is pivotal for the excellent reaction performance. On the basis of X-ray photoelectron spectroscopy (XPS) analysis, the critical role of CO was revealed, which is to maintain the metallic state of reactive Ir species during the oxidation cycles.
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http://dx.doi.org/10.1021/jacs.9b06986DOI Listing
December 2019

Anchoring Cu species over nanodiamond-graphene for semi-hydrogenation of acetylene.

Nat Commun 2019 09 30;10(1):4431. Epub 2019 Sep 30.

Beijing National Laboratory for Molecular Engineering, College of Chemistry and Molecular Engineering and College of Engineering, BIC-ESAT, Peking University, 100871, Beijing, P. R. China.

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamond-graphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst.
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http://dx.doi.org/10.1038/s41467-019-12460-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768864PMC
September 2019

Orange to Red, Emission-Tunable Mn-Doped Two-Dimensional Perovskites with High Luminescence and Stability.

ACS Appl Mater Interfaces 2019 Sep 5;11(37):34109-34116. Epub 2019 Sep 5.

Hebei Provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving, School of Chemical Engineering and Technology , Hebei University of Technology , Tianjin 300130 , P. R. China.

Lead halide perovskites are emerging as promising candidates for high-efficiency light-emitting diode (LED) applications because of their tunable band gaps and high quantum yield (QY). However, it remains a challenge to obtain stable red emitting materials with high QY. Herein, we report a facile and convenient hot-injection strategy to synthesize Mn-doped two-dimensional (2D) perovskite nanosheets. The emission peak can be tuned from 597 to 658 nm by manipulating the crystal field strength. In particular, a QY as high as 97% for 2D perovskite is achieved. The as-prepared perovskite also possesses excellent stability, whose emission property can be maintained for almost one year. A monochrome LED is further fabricated by employing the as-prepared perovskite as phosphor, which also shows high long-term stability. We believe that these highly efficient and stable perovskites will open up new opportunities in LED applications.
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http://dx.doi.org/10.1021/acsami.9b11665DOI Listing
September 2019

A versatile route to fabricate single atom catalysts with high chemoselectivity and regioselectivity in hydrogenation.

Nat Commun 2019 Aug 14;10(1):3663. Epub 2019 Aug 14.

Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China.

Preparation of single atom catalysts (SACs) is of broad interest to materials scientists and chemists but remains a formidable challenge. Herein, we develop an efficient approach to synthesize SACs via a precursor-dilution strategy, in which metalloporphyrin (MTPP) with target metals are co-polymerized with diluents (tetraphenylporphyrin, TPP), followed by pyrolysis to N-doped porous carbon supported SACs (M/N-C). Twenty-four different SACs, including noble metals and non-noble metals, are successfully prepared. In addition, the synthesis of a series of catalysts with different surface atom densities, bi-metallic sites, and metal aggregation states are achieved. This approach shows remarkable adjustability and generality, providing sufficient freedom to design catalysts at atomic-scale and explore the unique catalytic properties of SACs. As an example, we show that the prepared Pt/N-C exhibits superior chemoselectivity and regioselectivity in hydrogenation. It only converts terminal alkynes to alkenes while keeping other reducible functional groups such as alkenyl, nitro group, and even internal alkyne intact.
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http://dx.doi.org/10.1038/s41467-019-11619-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694111PMC
August 2019

Molybdenum Carbide: Controlling the Geometric and Electronic Structure of Noble Metals for the Activation of O-H and C-H Bonds.

Acc Chem Res 2019 Dec 14;52(12):3372-3383. Epub 2019 Aug 14.

Beijing National Laboratory for Molecular Engineering, College of Chemistry and Molecular Engineering and College of Engineering, BIC-ESAT , Peking University , Beijing 100871 , P. R. China.

In the field of heterogeneous catalysis, transition metal carbides (TMCs) have attracted growing and extensive attention as a group of important catalytic materials for a variety of energy-related reactions. Due to the incorporation of carbon atoms at the interstitial sites, TMCs possess much higher density of states near the Fermi level, endowing the material with noble-metal-like electron configuration and catalytic behaviors. Crystal structure, site occupancies, surface termination, and metal/carbon defects in the bulk phase or at the surface are the structural factors that influence the behavior of the TMCs in catalytic reactions. In the early studies of heterogeneous catalytic applications of TMCs, the carbide itself was used individually as the catalytically active site, which exhibited unique catalytic performance comparable to precious metal catalysts toward hydrogenation, dehydrogenation, isomerization, and hydrodeoxygenation. To promote the catalytic performance, the doping of secondary transition metals into the carbide lattice to form bimetallic carbides was extensively studied. As a recent development, the utilization of TMCs as functionalized catalyst supports has achieved a series of significant breakthroughs in low-temperature catalytic applications, including the reforming of alcohols, water-gas shift reactions, and the hydrogenation of functional groups for chemical production and biomass conversion. Generally, the excellence of TMCs as supports is attributed to three factors: the modulation of geometric and electronic structures of the supported metal centers, the special reactivity of TMC supports that accelerates certain elementary step and influences the surface coverage of intermediates, and the special interfacial properties at the metal-carbide interface that enhance the synergistic effect. In this Account, we will review recent discoveries from our group and other researchers on the special catalytic properties of face-centered cubic MoC (α-MoC) as both a special catalyst and a functional support that enables highly efficient low-temperature O-H bond activation for several important energy-related catalytic applications, including hydrogen evolution from aqueous phase methanol reforming, ultralow temperature water-gas shift reaction, and biomass conversion. In particular, α-MoC has been demonstrated to exhibit unprecedented strong interaction with the supported metals compared with other TMCs, which not only stabilizes the under-coordinated metal species (single atoms and layered clusters) under strong thermal perturbation and harsh reaction conditions but also tunes the charge density at the metal sites and modifies their catalytic behavior in C-H activation and CO chemisorption. We will discuss how to exploit the metal/α-MoC interaction and interfacial properties to construct CO-tolerant selective hydrogenation catalysts for nitroarene derivatives. Several examples of constructing bifunctional tandem catalytic systems using molybdenum carbides that enable hydrogen extraction and utilization in one-pot conversion of biomass substrates and Fischer-Tropsch synthesis are also highlighted.
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http://dx.doi.org/10.1021/acs.accounts.9b00182DOI Listing
December 2019

Zn-O Dual-Spin Surface State Formation by Modification of ZnO Nanoparticles with Diboron Compounds.

Langmuir 2019 Nov 27;35(44):14173-14179. Epub 2019 Aug 27.

Department of Energy and Resources Engineering, College of Engineering , Peking University , Beijing 100871 , China.

ZnO semiconductor oxides are versatile functional materials that are used in photoelectronics, catalysis, sensing, etc. The Zn-O surface electronic states of semiconductor oxides were formed on the ZnO surface by Zn 4s and O 2p orbital coupling with the diboron compound's B 2p orbitals. The formation of spin-coupled surface states was based on the spin-orbit interaction on the interface, which has not been reported before. This shows that the semiconductor oxide's spin surface states can be modulated by regulating surface orbital energy. The Zn-O surface electronic states were confirmed by electron spin resonance results, which may help in expanding the fundamental research on spintronics modulation and quantum transport.
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http://dx.doi.org/10.1021/acs.langmuir.9b01955DOI Listing
November 2019

Multi-quantum-well quantum dots with stable dual emission.

Nanoscale 2019 Apr;11(17):8475-8484

State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei, P. R. China.

Multi-quantum-well quantum dots (MQW-QDs) with multiple emission peaks have been evaluated as promising single source emitters in the fabrication of high performance white LEDs. However, they still face a critical issue of color shift in practical applications, which is mainly attributed to the redistribution of the excitons between the adjacent wells under different excitation powers. Herein, we report sandwich structural MQW-QDs that provide highly stable dual emission. The study on the optical properties and exciton dynamics reveals that the thickness of the inner-barrier plays a crucial role in balancing the exciton distribution through regulating near-field energy transfer and light absorption between the adjacent wells. Meanwhile, the wells and the outer-barrier mainly influence the luminescence efficiency and the wavelength control of the dual emission peaks. The MQW-QDs with a minimum color shift versus excitation power are finally achieved by optimizing the structure parameters. A white LED based on the developed MQW-QDs exhibits a stable white light spectrum with high tolerance to the change of the excitation power, ensuring the advancement of the performance of MQW-QDs in lighting and display applications.
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http://dx.doi.org/10.1039/c9nr00177hDOI Listing
April 2019

A highly CO-tolerant atomically dispersed Pt catalyst for chemoselective hydrogenation.

Nat Nanotechnol 2019 04 25;14(4):354-361. Epub 2019 Feb 25.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, College of Engineering and BIC-ESAT, Peking University, Beijing, China.

The hydrogenation activity of noble metal, especially platinum (Pt), catalysts can be easily inhibited by the presence of a trace amount of carbon monoxide (CO) in the reaction feeds. Developing CO-resistant hydrogenation catalysts with both high activity and selectivity is of great economic interest for industry as it allows the use of cheap crude hydrogen and avoids costly product separation. Here we show that atomically dispersed Pt over α-molybdenum carbide (α-MoC) constitutes a highly CO-resistant catalyst for the chemoselective hydrogenation of nitrobenzene derivatives. The Pt/α-MoC catalyst shows promising activity in the presence of 5,000 ppm CO, and has a strong chemospecificity towards the hydrogenation of nitro groups. With the assistance of water, high hydrogenation activity can also be achieved using CO and water as a hydrogen source, without sacrificing selectivity and stability. The weakened CO binding over the electron-deficient Pt single atom and a new reaction pathway for nitro group hydrogenation confer high CO resistivity and chemoselectivity on the catalyst.
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http://dx.doi.org/10.1038/s41565-019-0366-5DOI Listing
April 2019

Ammonia-Responsive Luminescence of Ln-β-diketonate Complex Encapsulated within Zeolite Y.

Molecules 2019 Feb 14;24(4). Epub 2019 Feb 14.

Hebei provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving, School of Chemical Engineering and Technology, Hebei University of Technology, GuangRong Dao 8, Hongqiao District, Tianjin 300130, China.

Assembling Ln(HPBA) (Ln = Eu or Tb, HPBA = N-(2-pyridinyl)benzoylacetamide) in the cavities of zeolite Y (ZY) via the "ship-in-a-bottle" strategy leads to the formation of novel luminescent composite, Ln(HPBA)@ZY, whose luminescence can be easily modulated by ammonia on the basis of the energy level variation of HPBA after deprotonation process. Additionally the bimetallic complex doping sample, EuTb(HPBA)@ZY, show great potential as self-referencing luminescent sensor for detecting low ammonia concentration of 10⁻0.25 wt%.
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http://dx.doi.org/10.3390/molecules24040685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412632PMC
February 2019

Solvent Tunes the Selectivity of Hydrogenation Reaction over α-MoC Catalyst.

J Am Chem Soc 2018 10 23;140(43):14481-14489. Epub 2018 Oct 23.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, and BIC-ESAT , Peking University , Beijing 100871 , P. R. China.

Selective activation of chemical bonds in multifunctional oxygenates on solid catalysts is a crucial challenge for sustainable biomass upgrading. Molybdenum carbides and nitrides preferentially activate C═O and C-OH bonds over C═C and C-C bonds in liquid-phase hydrogenation of bioderived furfural, leading to highly selective formations of furfuryl alcohol (FA) and its subsequent hydrogenolysis product (2-methyl furan (2-MF)). We demonstrate that pure-phase α-MoC is more active than β-MoC and γ-MoN for catalyzing furfural hydrogenation, and the hydrogenation selectivity on these catalysts can be conveniently manipulated by alcohol solvents without significant changes in reaction rates (e.g., > 90% yields of FA in methanol solvent and of 2-MF in 2-butanol solvent at 423 K). Combined experimental and theoretical assessments of these solvent effects unveil that it is the hydrogen donating ability of the solvents that governs the hydrogenation rate of the reactants, while strong dissociative adsorption of the alcohol solvent on Mo-based catalysts results in surface decoration which controls the reaction selectivity via enforcing steric hindrance on the formation of relevant transient states. Such solvent-induced surface modification of Mo-based catalysts provides a compelling strategy for highly selective hydrodeoxygenation processes of biomass feedstocks.
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http://dx.doi.org/10.1021/jacs.8b09310DOI Listing
October 2018

Atomically Dispersed Pd on Nanodiamond/Graphene Hybrid for Selective Hydrogenation of Acetylene.

J Am Chem Soc 2018 10 26;140(41):13142-13146. Epub 2018 Sep 26.

Beijing National Laboratory for Molecular Engineering , College of Chemistry and Molecular Engineering and College of Engineering, BIC-ESAT, Peking University , Beijing 100871 , People's Republic of China.

We reported here a strategy to use a defective nanodiamond-graphene (ND@G) to prepare an atomically dispersed metal catalyst, i.e., in the current case atomically dispersed palladium catalyst which is used for selective hydrogenation of acetylene in the presence of abundant ethylene. The catalyst exhibits remarkable performance for the selective conversion of acetylene to ethylene: high conversion (100%), ethylene selectivity (90%), and good stability. The unique structure of the catalyst (i.e., atomically dispersion of Pd atoms on graphene through Pd-C bond anchoring) blocks the formation of unselective subsurface hydrogen species and ensures the facile desorption of ethylene against the overhydrogenation to undesired ethane, which is the key for the outstanding selectivity of the catalyst.
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http://dx.doi.org/10.1021/jacs.8b07476DOI Listing
October 2018

Effect of Added Mullite Whisker on Properties of Lithium Aluminosilicate (LAS) Glass-Ceramics Prepared for Dental Restoration.

J Biomed Nanotechnol 2018 Nov;14(11):1944-1952

In this work, lithium aluminosilicate (LAS) glass-ceramics were prepared from lithium disilicate glass powder and mullite whiskers. Lithium disilicate glass powder (28.6Li-68.6Si-2K-0.8La, mol.%) with contents of 5, 10 and 15 wt.% mullite whiskers were hot-pressed at 860 °C for 1 h. The effects of added mullite on phase composition, microstructure, mechanical properties, coefficient of thermal expansion (CTE) and translucency were systematically studied. Also, the mechanism for phase transformation and grain growth was discussed. The LAS glass-ceramic samples exhibited relative densities above 98% with main crystalline phases of lithium disilicate (Li2Si2O5, LD), lithium silicate (Li2SiO3, LM), and β-spodumene (LiAlSi2O6). The β-spodumene whiskers were in-situ synthesized through the reaction between mullite whiskers and glass matrix. As β-spodumene fraction rose, lithium disilicate crystals content decreased and that of lithium silicate increased, resulting in declined bending strength and improved fracture toughness. The composite containing 10 wt.% mullite whisker showed optimal performance with bending strength above 300 MPa and fracture toughness of 2.7 MPa·m1/2. The formation of β-spodumene in the obtained composite declined CTE, with values ranging from 10.5×106 °C-1 for LD glass-ceramic to 6.03×10-6 °C-1 for LAS glass-ceramic doped with 15 wt.% mullite whiskers. Finally, though the real in-line transmission of obtained glass-ceramic composites declined as β-spodumene content rose, the specimens containing less than 10 wt.% mullite whiskers showed favorable translucency, which would suit applications in dental restoration.
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http://dx.doi.org/10.1166/jbn.2018.2637DOI Listing
November 2018

De novo transcriptomic analysis of the venomous glands from the scorpion Heterometrus spinifer revealed unique and extremely high diversity of the venom peptides.

Toxicon 2018 Mar 2;143:1-19. Epub 2018 Jan 2.

Department of Marine Biotechnology, Faculty of Naval Medicine, Second Military Medical University, Shanghai, 200433, China. Electronic address:

Scorpion, as an ancient species, has been widely used on dozens of human diseases in traditional Chinese Medicine. Although the scorpion venom from the Buthidae family with the potent toxicity attracts more interests, toxins from the non-Buthidae family draw great attention as well because of its abundance and complexity even without harm to mammals. Moreover, several toxic components of scorpion venom have been identified as valuable scaffolds for the drug design and development. Using the Next Generation Sequencing (NGS) technique, here we reported the transcriptome of the venomous glands of Heterometrus spinifer, a non-Buthidae scorpion that only a few toxic and complete components have been identified known-to-date. The total mRNA extracted from the venomous glands of H. spinifer was subjected to illumina sequencing with a strategy of de novo assembly, and a total of 54 189 transcripts were unigenes from a total of 88 311 600 determined reads. We annotated 18 567 (34.26%) unigenes from NR database, 12 258 (22.62%) from SWISSPROT database, 11 161 (20.60%) from GO database, 10 159 (18.75%) from COG database and 5059 (9.34%) from KEGG database, respectively. 2843 unigenes were further selected against the toxin-related sub-database of SWISSPROT. After removing the redundancy, 13 common toxin-related subfamilies with 62 unigenes were manually confirmed, including 8 K-toxins, 1 calcin, 3 Imperatoxin I-like, 2 La1-like, 1 scorpin-like, 3 antimicrobial peptides, two types of protease inhibitors such as 8 Kunitz-type protease inhibitors and 3 Ascaris-type protease inhibitors, and 33 proteases including 16 serine proteinases, 7 phospholipases, 5 metalloproteases, 3 hyaluronidases and 2 phosphatases. Our report is the first transcriptomic analyses of venomous glands from the scorpion H. spinifer, serving as a public information platform for the development of novel bio-therapeutics.
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http://dx.doi.org/10.1016/j.toxicon.2017.12.051DOI Listing
March 2018

Tuning the Selectivity of Catalytic Carbon Dioxide Hydrogenation over Iridium/Cerium Oxide Catalysts with a Strong Metal-Support Interaction.

Angew Chem Int Ed Engl 2017 08 1;56(36):10761-10765. Epub 2017 Aug 1.

College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

A one-step ligand-free method based on an adsorption-precipitation process was developed to fabricate iridium/cerium oxide (Ir/CeO ) nanocatalysts. Ir species demonstrated a strong metal-support interaction (SMSI) with the CeO substrate. The chemical state of Ir could be finely tuned by altering the loading of the metal. In the carbon dioxide (CO ) hydrogenation reaction it was shown that the chemical state of Ir species-induced by a SMSI-has a major impact on the reaction selectivity. Direct evidence is provided indicating that a single-site catalyst is not a prerequisite for inhibition of methanation and sole production of carbon monoxide (CO) in CO hydrogenation. Instead, modulation of the chemical state of metal species by a strong metal-support interaction is more important for regulation of the observed selectivity (metallic Ir particles select for methane while partially oxidized Ir species select for CO production). The study provides insight into heterogeneous catalysts at nano, sub-nano, and atomic scales.
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http://dx.doi.org/10.1002/anie.201705002DOI Listing
August 2017

FIRT: Filtered iterative reconstruction technique with information restoration.

J Struct Biol 2016 07 29;195(1):49-61. Epub 2016 Apr 29.

National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing, China; Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China. Electronic address:

Electron tomography (ET) combining subsequent sub-volume averaging has been becoming a unique way to study the in situ 3D structures of macromolecular complexes. However, information missing in electron tomography due to limited angular sampling is still the bottleneck in high-resolution electron tomography application. Here, based on the understanding of smooth nature of biological specimen, we present a new iterative image reconstruction algorithm, FIRT (filtered iterative reconstruction technique) for electron tomography by combining the algebra reconstruction technique (ART) and the nonlinear diffusion (ND) filter technique. Using both simulated and experimental data, in comparison to ART and weight back projection method, we proved that FIRT could generate a better reconstruction with reduced ray artifacts and significant improved correlation with the ground truth and partially restore the information at the non-sampled angular region, which was proved by investigating the 90° re-projection and by the cross-validation method. This new algorithm will be subsequently useful in the future for both cellular and molecular ET with better quality and improved structural details.
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http://dx.doi.org/10.1016/j.jsb.2016.04.015DOI Listing
July 2016

ICON: 3D reconstruction with 'missing-information' restoration in biological electron tomography.

J Struct Biol 2016 07 11;195(1):100-12. Epub 2016 Apr 11.

National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address:

Electron tomography (ET) plays an important role in revealing biological structures, ranging from macromolecular to subcellular scale. Due to limited tilt angles, ET reconstruction always suffers from the 'missing wedge' artifacts, thus severely weakens the further biological interpretation. In this work, we developed an algorithm called Iterative Compressed-sensing Optimized Non-uniform fast Fourier transform reconstruction (ICON) based on the theory of compressed-sensing and the assumption of sparsity of biological specimens. ICON can significantly restore the missing information in comparison with other reconstruction algorithms. More importantly, we used the leave-one-out method to verify the validity of restored information for both simulated and experimental data. The significant improvement in sub-tomogram averaging by ICON indicates its great potential in the future application of high-resolution structural determination of macromolecules in situ.
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http://dx.doi.org/10.1016/j.jsb.2016.04.004DOI Listing
July 2016

Broad hexagonal columnar mesophases formation in bioinspired transition-metal complexes of simple fatty acid meta-octaester derivatives of meso-tetraphenyl porphyrins.

Chemistry 2015 Feb 23;21(9):3671-81. Epub 2015 Jan 23.

Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China).

A series of meta-substituted fatty acid octaester derivatives and their transition-metal complexes of meso- tetraphenyl porphyrins (TPP-8OOCR, with R = C(n-1)H(2n-1), n = 8, 12, or 16) have been prepared through very simple synthesis protocols. The thermotropic phase behavior and the liquid crystalline (LC) organization structures of the synthesized porphyrin derivatives were systematically investigated by a combination of differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable-temperature small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS) techniques. The shorter octanoic acid ester substituted porphyrin (C8-TPP) did not show liquid crystallinity and its metal porphyrins exhibited an uncommon columnar mesophase. The lauric acid octaester (C12-TPP) and the palmitic acid octaester (C16-TPP) series porphyrins generated hexagonal columnar mesophase Colh. Moreover, the metal porphyrins C12-TPPM and C16-TPPM with M = Zn, Cu, or Ni, exhibited well-organized Colh mesophases of broad LC temperature ranges increasing in the order of TPPNi
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http://dx.doi.org/10.1002/chem.201404708DOI Listing
February 2015

A PH domain in ACAP1 possesses key features of the BAR domain in promoting membrane curvature.

Dev Cell 2014 Oct 2;31(1):73-86. Epub 2014 Oct 2.

National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. Electronic address:

The BAR (Bin-Amphiphysin-Rvs) domain undergoes dimerization to produce a curved protein structure, which superimposes onto membrane through electrostatic interactions to sense and impart membrane curvature. In some cases, a BAR domain also possesses an amphipathic helix that inserts into the membrane to induce curvature. ACAP1 (Arfgap with Coil coil, Ankyrin repeat, and PH domain protein 1) contains a BAR domain. Here, we show that this BAR domain can neither bind membrane nor impart curvature, but instead requires a neighboring PH (Pleckstrin Homology) domain to achieve these functions. Specific residues within the PH domain are responsible for both membrane binding and curvature generation. The BAR domain adjacent to the PH domain instead interacts with the BAR domains of neighboring ACAP1 proteins to enable clustering at the membrane. Thus, we have uncovered the molecular basis for an unexpected and unconventional collaboration between PH and BAR domains in membrane bending.
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http://dx.doi.org/10.1016/j.devcel.2014.08.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4198613PMC
October 2014