Publications by authors named "Wenshu Yang"

27 Publications

  • Page 1 of 1

Design and Evaluation of an Ultrahigh-Strength Coral Aggregate Concrete for Maritime and Reef Engineering.

Materials (Basel) 2021 Oct 7;14(19). Epub 2021 Oct 7.

School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.

In this paper, an ultrahigh-strength marine concrete containing coral aggregates is developed. Concrete fabricated from marine sources is considered an effective and economical alternative for marine engineering and the construction of remote islands. To protect sea coral ecosystems, the coral aggregates used for construction are only efflorescent coral debris. To achieve the expected mechanical performance from the studied concrete, an optimal mixture design is conducted to determine the optimal proportions of components, in order to optimize the compressive strength. The mechanical properties and the autogenous shrinkage, as well as the heat flow of early hydration reactions, are measured. The hydration products fill up the pores of coral aggregates, endowing our concrete with flowability and self-compacting ability. The phases in the marine concrete are identified via X-ray diffraction analysis. The 28-day compressive and flexural strength of the developed marine concrete achieve 116.76 MPa and 18.24 MPa, respectively. On account of the lower cement content and the internal curing provided by coral aggregates, the volume change resulting from autogenous shrinkage is only 63.11% of that of ordinary reactive powder concrete.
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http://dx.doi.org/10.3390/ma14195871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8510195PMC
October 2021

The Impact of Aging Policy on Societal Age Stereotypes and Ageism.

Gerontologist 2021 Oct 12. Epub 2021 Oct 12.

Lloyd's Register Institute for the Public Understanding of Risk, National University of Singapore, Singapore, Singapore.

Background And Objectives: While studies have researched ageism in public policy, few investigated the impact of aging policy on ageism-typically, an unintended consequence. Ageism is linked to $63 billion in healthcare cost, so its antecedents are of interest. We test the association between Aging-Policy-Agenda-Setting and Societal-Age-Stereotypes; and hypothesize a mediating pathway via Medicalization-of-Aging, moderated by demographics.

Research Design And Methods: Scholars identified Singapore's Pioneer-Generation-Policy (PGP) as one of the largest policy implementations in recent years, where the agenda was set by the Prime Minister at an equivalent State-of-the-Union address in 2013, and US$7 billion allocated to fund outpatient healthcare costs for aged 65 years/older. Over 400,000 older adults received a PGP card and home visits by trained volunteers who co-devised a personalized utilization plan. We leveraged a 10-billion-word dataset with over 30 million newspaper and magazine articles to dynamically track Societal-Age-Stereotype scores over 8 years from pre-to-post policy implementation.

Results: Societal-Age-Stereotypes followed a quadratic trend: Prior to the Aging-Policy-Agenda-Setting from 2010-2014, stereotypes were trending positive; after 2014, it trended downwards to become more negative. Medicalization-of-Aging mediated the relationship between Aging-Policy-Agenda-Setting and Societal-Age-Stereotypes. Further, Old-age-Support-Ratio moderated the mediational model, suggesting that the impact of Policy on Medicalization is stronger when a society is more aged.

Discussion And Implications: We provided a framework for policy makers to ameliorate the unintended consequences of aging policies on societal ageism-if unaddressed, it will exert an insidious toll on older adults, even if initial policies are well-intentioned.
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http://dx.doi.org/10.1093/geront/gnab151DOI Listing
October 2021

Spark Plasma Sintering of AlN/Al Functionally Graded Materials.

Materials (Basel) 2021 Aug 27;14(17). Epub 2021 Aug 27.

School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.

In this paper, six-layer AlN/Al gradient composites were prepared by a spark plasma sintering process to study the influences of sintering temperature and holding time on the microstructure and mechanical properties. The well-bonded interface enables the composite to exhibit excellent thermal and mechanical properties. The hardness and thermal expansion properties of the composite exhibit a gradient property. The hardness increased with the volume fraction of AlN while the CTE decreased as the volume fraction of AlN. The thermal expansion reaches the lowest value of 13-14 ppm/K, and the hardness reaches the maximum value of 1.25 GPa, when the target volume fraction of AlN is 45%. The simulation results show that this gradient material can effectively reduce the thermal stress caused by the mismatch of the thermal expansion coefficient as a transmitter and receiver (T/R) module. This paper attempts to provide experimental support for the preparation of gradient Al matrix composites.
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http://dx.doi.org/10.3390/ma14174893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432733PMC
August 2021

Effect of Microstructure on the Dimensional Stability of Extruded Pure Aluminum.

Materials (Basel) 2021 Aug 24;14(17). Epub 2021 Aug 24.

School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.

High-performance extruded aluminum alloys with complex textures suffer significant dimension variation under environmental temperature fluctuations, dramatically decreasing the precision of navigation systems. This research mainly focuses on the effect of the texture of extruded pure aluminum on its dimensional stability after various annealing processes. The result reveals that a significant increment in the area fraction of recrystallized grains with <100> orientation and a decrement in the area fraction of grains with <111> orientation were found with increasing annealing temperature. Moreover, with the annealing temperature increasing from 150 °C to 400 °C, the residual plastic strain after twelve thermal cycles with a temperature range of 120 °C was changed from -1.6 × 10 to -4.5 × 10. The large amount of equiaxed grains with <100> orientation was formed in the microstructure of the extruded pure aluminum and the average grain size was decreased during thermal cycling. The area fraction of grain with <100> crystallographic orientation of the sample annealed at 400 °C after thermal cycling was 30.9% higher than annealed at 350 °C (23.7%) or at 150 °C (18.7%). It is attributed to the increase in the proportion of recrystallization grains with <100> direction as the annealing temperature increases, provided more nucleation sites for the formation of fine equiaxed grains with <100> orientation. The main orientation of the texture was rotated from parallel to <111> to parallel to <100> after thermal cycling. The change in the orientation of grains contributed to a change in interplanar spacing, which explains the change in the dimension along the extrusion direction during thermal cycling.
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http://dx.doi.org/10.3390/ma14174797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432486PMC
August 2021

News media narratives of Covid-19 across 20 countries: Early global convergence and later regional divergence.

PLoS One 2021 1;16(9):e0256358. Epub 2021 Sep 1.

Lloyd's Register Institute for the Public Understanding of Risk, National University of Singapore, Singapore, Singapore.

Background: Seldom in history does one get a 'front row seat'-with large-scale dynamic data-on how online news media narratives shift with a global pandemic. News media narratives matter because they shape societal perceptions and influence the core tent poles of our society, from the economy to elections. Given its importance-and with the benefit of hindsight-we provide a systematic framework to analyze news narratives of Covid-19, laying the groundwork to evaluate policy and risk communications.

Objectives: We leverage a 10-billion-word-database of online news, taken from over 7,000 English newspapers and magazines across 20 countries, culminating in 28 million articles. First, we track the volume of Covid-19 conversations across 20 countries from before to during the pandemic (Oct'19 to May'20). Second, we distill the phases of global pandemic narratives, and elucidate regional differences.

Methods: To track the volume of Covid-19 narratives, we identified 10 target terms-Coronavirus, Covid-19, Covid, nCoV, SARS-CoV-2, Wuhan Virus, Virus, Disease, Epidemic, Pandemic-and tracked their combined monthly prevalence across eight months from October 2019 through May 2020. Globally, across 20 countries, we identified 18,042,855 descriptors of the target terms. Further, these descriptors were analysed with natural language processing models to generate the top five topics of Covid-19 that were labelled by two independent researchers. This process was repeated across six continents to distil regional topics.

Results: Our model found four phases of online news media narratives: Pre-pandemic, Early, Peak and Recovery. Pre-pandemic narratives (Oct'19-Dec'19) were divergent across regions with Africa focused on monkeypox, Asia on dengue fever, and North America on Lyme disease and AIDS. Early (Jan-Feb'20) and Peak Pandemic (Mar-May'20) evidenced a global convergence, reflecting the omnipresence of Covid-19. The brief transition from early to peak pandemic narratives underscored the pandemic's rapid spread. Emerging from the embers of the pandemic's peak were nascent recovery words that are regionally divergent-Oceania focused on hope and an uncertain future while North America centered on re-opening the economy and tackling discrimination.

Conclusions: Practically, we presented a media barometer of Covid-19, and provided a framework to analyse the pandemic's impact on societal perceptions-laying the important groundwork for policy makers to evaluate policy communications, and design risk communication strategies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0256358PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8409659PMC
September 2021

Discharge-Induced Enhancement of the Oxygen Evolution Reaction.

Angew Chem Int Ed Engl 2021 Sep 6;60(36):20042-20048. Epub 2021 Aug 6.

School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, P. R. China.

The fundamental understanding of the surface reconstruction induced by the applied potential is of great significance for enhancing the oxygen evolution reaction (OER). Here, we show that a previously overlooked discharge current in the low applied potential region also leads to in situ electrochemical activation of a nitrogen-doped nickel oxyhydroxide surface. We exploit the fact that doping of heteroatoms weakens the surface structure, and hence, a weak discharge current originating from the capacitive nature of nickel oxyhydroxide has a strong structure-reforming ability to promote the formation of nitrogen and oxygen vacancies. The current density at 1.4 V (vs. Hg/HgO) can dramatically increase by as much as 31.3 % after discharge in the low applied potential region. This work provides insight into in situ enhancement of the OER and suggests that the low applied potential region must be a primary consideration in evaluating the origin of the activity of electrocatalysts.
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http://dx.doi.org/10.1002/anie.202108770DOI Listing
September 2021

Phosphorus doped nickel selenide for full device water splitting.

J Colloid Interface Sci 2021 Nov 10;602:115-122. Epub 2021 Jun 10.

School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China. Electronic address:

The lack of high active and stable electrocatalysts has impeded the development of electrochemical water splitting device, which is promising technique for renewable energy conversion system. Here, we report a one-step protocol to synthesize P doped NiSe (P-NiSe) by selenylation process derived from nickel foam with assistant of NaHPO and Se powder. The P-NiSe could be directly used as working electrode and shows the superior electrochemical activity, offering current density of 10 mA cm with overpotential of 270 mV for OER and 71 mV for HER. The enhanced electrochemical activity can be ascribed to the P atom doping. The P atom doping leads to the high valence state of Ni active sites, which have high catalytic ability towards OER. Moreover, the P doping makes the d-band center of Ni atoms in P-NiSe move close to Fermi level, facilitating the HER kinetics with respect to proton adsorption and hydrogen desorption. When employed P-NiSe as both anodic and cathodic electrode in alkaline water electrolyzer, a current density of 10 mA cm can be achieved at 1.58 V. Our work highlights the importance of P doping in determining the surface electron configuration for full device water splitting and the facile synthesis protocol would be promising for realistic applications.
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http://dx.doi.org/10.1016/j.jcis.2021.06.013DOI Listing
November 2021

KIT-6 induced mesostructured TiO for photocatalytic degradation of methyl blue.

Environ Sci Pollut Res Int 2021 Oct 24;28(38):53340-53352. Epub 2021 May 24.

Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore, Pakistan.

In this study, titania/silica nanocomposite and mesoporous TiO (m-TiO) photocatalysts are developed by KIT-6 template via a sol-gel approach. The synthesized photocatalysts are characterized by XRD, EDX, SEM, Raman, PL, and UV-vis DRS analysis techniques. The as-synthesized series revealed a high surface area, smaller size, a greater number of accessible active sites, and enhanced light-harvesting capability. The m-TiO photocatalysts' charge recombination capability was curiously inferior to the rest of as-synthesized TiO/KIT-6 nanocomposite materials. The band-gap of as-synthesized materials were suitable for their activity in UV light irradiations. It was pragmatic that the photocatalytic degradation efficiency of m-TiO photocatalysts was superior as compared to that of commercial TiO photocatalyst under UV light irradiations, owing to the synergistic outcome of the anatase phase and a greater number of accessible active-sites availability as a result of high surface area. Moreover, the m-TiO was critically evaluated by investigating various parameters affecting the photocatalytic degradation reaction of MB including the effect of irradiation time, pH, catalyst dosage, and dye concentration. The m-TiO, 45wt% composite material and commercial-TiO exhibited 99.27, 91.20, and 84.67% degradation of methyl blue in 50 min, respectively. Finally, the m-TiO exhibited excellent recyclability with negligible loss of activity performance.
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http://dx.doi.org/10.1007/s11356-021-14442-zDOI Listing
October 2021

Culture Linked to Increasing Ageism during Covid-19: Evidence from a 10-billion-word Corpus across 20 Countries.

J Gerontol B Psychol Sci Soc Sci 2021 Mar 31. Epub 2021 Mar 31.

Lloyd's Register Institute for the Public Understanding of Risk, National University of Singapore, Singapore.

Objectives: Older adults experience higher risks of getting severely ill from COVID-19, resulting in widespread narratives of frailty and vulnerability. We test: (1) Whether global aging narratives have become more negative from before to during the pandemic (Oct'19 to May'20) across 20 countries; (2) Model pandemic (incidence and mortality), and cultural factors associated with the trajectory of aging narratives.

Methods: We leveraged a 10-billion-word online-media corpus, consisting of 28 million newspaper and magazine articles across 20 countries, to identify nine common synonyms of 'older adults' and compiled their most frequently-used descriptors (collocates) from Oct'19 to May'20-culminating in 11,504 collocates that were rated to create a Cumulative-Aging-Narrative-Score-(CANS) per month. Widely used cultural dimension scores were taken from Hofstede, and pandemic variables, from the Oxford COVID-19 Government Response Tracker.

Results: Aging narratives became more negative as the pandemic worsened across 20 countries. Globally, scores were trending neutral from Oct'19 to Feb'20, and plummeted in Mar'20, reflecting COVID-19's severity. Pre-pandemic (Oct'19), UK evidenced the most negative aging narratives; peak-pandemic (May'20), South Africa took on the dubious honor. Across the 8-month period, Philippines experienced the steepest trend towards negativity in aging narratives. Ageism, during the pandemic, was ironically, not predicted by COVID-19's incidence and mortality rates, but by cultural variables: Individualism, Masculinity, Uncertainty Avoidance, and Long-term Orientation.

Discussion: The strategy to reverse this trajectory lay in the same phenomenon that promoted it: A sustained global campaign-though, it should be culturally nuanced and customized to a country's context.
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http://dx.doi.org/10.1093/geronb/gbab057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8083600PMC
March 2021

Au/CdS Core-Shell Sensitized Actinomorphic Flower-Like ZnO Nanorods for Enhanced Photocatalytic Water Splitting Performance.

Nanomaterials (Basel) 2021 Jan 17;11(1). Epub 2021 Jan 17.

State Key Laboratory of Superhard Materials, Jilin University, Qianjin Street 2699, Changchun 130012, China.

Herein, a novel actinomorphic flower-like ZnO/Au/CdS nanorods ternary composite photocatalyst is prepared to extend the light-responsive range, reduce the photogenerated charge carriers recombination, and ultimately improve the water splitting performance. Flower-like ZnO nanorods are synthesized by a chemical bath method and the CdS nanoparticles are sensitized by successive ionic layer adsorption and reaction method. Then the Au nanoparticles as co-catalysts are introduced by the photodeposition method to modify the interface of ZnO/CdS for reducing the photogenerated electron recombination rate and further improving the performance of water splitting. Detailed characterizations and measurements are employed to analyse the crystallinity, morphology, composition, and optical properties of the flower-like ZnO/Au/CdS nanorods samples. As a result, the flower-like ZnO/Au/CdS nanorod samples present significantly enhanced water splitting performance with a high gas evolution rate of 502.2 μmol/g/h, which is about 22.5 and 1.5 times higher than that of the pure ZnO sample and ZnO/CdS sample. The results demonstrate that the flower-like ZnO/Au/CdS nanorods ternary composite materials have great application potential in photocatalytic water splitting for the hydrogen evolution field.
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http://dx.doi.org/10.3390/nano11010233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830535PMC
January 2021

Self-supported nickel sulfide derived from nickel foam for hydrogen evolution and oxygen evolution reaction: effect of crystal phase switching.

Nanotechnology 2021 Feb;32(8):085710

School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, People's Republic of China.

Designing and fabricating economically viable, high active and stable electrocatalysts play an important role for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Crystal phase is the crucial factor that governs the electrochemical property and electrocatalytic reaction pathways. Here, a one-step nickel foam derived sulfidation method was presented to synthesize self-supported NiS and NiS. The crystal phase-dependent chemical properties related to electrocatalytic behavior were evaluated by a series of advanced characterization and density functional theory calculations. Overall, the self-supported NiS shows high electrochemical activity towards both HER and OER in alkaline conditions, which afford the current density of 10 mA cm with overpotentials of 245 mV for OER and 123 mV for HER, respectively. When employed the self-supported NiS as the bifunctional electrocatalysts for overall water splitting, the entire device provides the current density of 10 mA cm at 1.61 V. These results indicate that the electrocatalytic properties can be exert greater improved by controlling the crystal phase, offering the prospect for advanced materials design and development.
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http://dx.doi.org/10.1088/1361-6528/abc852DOI Listing
February 2021

Incorporation of Nickel Ions to Enhance Integrity and Stability of Perovskite Crystal Lattice for High-Performance Planar Heterojunction Solar Cells.

ACS Appl Mater Interfaces 2020 Jan 17;12(1):904-913. Epub 2019 Dec 17.

State Key Laboratory of Superhard Materials , Jilin University , Qianjin Street 2699 , Changchun 130012 , People's Republic of China.

Enhancement of integrity and stability of crystal lattice are highly challenging for polycrystalline perovskite films. In this work, a strategy of incorporation of nickel (Ni) ions is presented to modulate the crystal structure of the CHNHPbI perovskite film. A broad range of experimental characterizations reveal that the incorporation of Ni ions can substantially eliminate the intrinsic halide vacancy defects, since Ni ions have a strong preference for octahedral coordination with halide ions, resulting in significantly improved integrity and short-range order of crystal lattice. Moreover, it is also demonstrated that the stronger chemical bonding interaction between Ni ions and halide ions as well as organic group can improve the stability of the perovskite material. Simultaneously, the surface morphology of the perovskite thin film is also improved by the incorporation of nickel ions. As a result, a planar heterojunction perovskite solar cell incorporated with 1.5% Ni exhibits a power conversion efficiency of 18.82%, which is improved by 25% compared with 14.92% for the pristine device. Simultaneously, the device formed incorpration of 1.5% Ni shows remarkable stability with 90% of the initial efficiency after storage in an air environment for 800 h. The studies provide a new insight into metal-incorporated perovskite materials for various optoelectronic applications.
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http://dx.doi.org/10.1021/acsami.9b19330DOI Listing
January 2020

Effect of Extrusion Temperature on the Microstructure and Mechanical Properties of SiCnw/2024Al Composite.

Materials (Basel) 2019 Aug 28;12(17). Epub 2019 Aug 28.

Harbin Institute of Technology, Harbin 150001, China.

In the present research work, the effect of extrusion temperature from 480 to 560 °C on the microstructure and mechanical behavior of the SiCnw/2024Al composite (15 vol.%) has been explored. It has been found that extrusion at higher temperature (above 520 °C) was beneficial for the densification of the composite, while the residual average length and alignment of the SiC nanowires were also increased with the extrusion temperature. Moreover, higher extrusion temperature was helpful for the mechanical strength of the SiCnw/2024Al composite, and the peak-aged SiCnw/2024Al composite extruded at 560 °C revealed the highest strength (709.4 MPa) and elastic modulus (109.8 GPa).
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http://dx.doi.org/10.3390/ma12172769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6747838PMC
August 2019

Carbon Nanotubes Grown on Graphite Films as Effective Interface Enhancement for an Aluminum Matrix Laminated Composite in Thermal Management Applications.

ACS Appl Mater Interfaces 2018 Nov 25;10(44):38350-38358. Epub 2018 Oct 25.

School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , P. R. China.

Uniform and dense carbon nanotubes (CNTs) were grown on the surface of the graphite film (GF) by a plasma-enhanced chemical vapor deposition process. The synthesized CNTs can act as a bridge between GF and Al matrix to enhance the interface performance and improve thermal properties of the GF/Al laminated composite simultaneously. A layer-by-layer CNTs-GF/Al composite with both increased mechanical property and thermal management capability was fabricated through an optimized pressure infiltration process, which was time- and energy-saving. The results show that the interface of the laminated composite is well bonded and no interface product such as AlC is generated. Additional investigations reveal that the growth of CNTs is an effective way to improve the thermal conductivity and reduce the coefficient of thermal expansion of the GF reinforced Al composites. Overall, the best-performing CNTs-GF/Al composites with a CNTs-GF volume fraction of 51.42% show an increase of 47.99% in thermal conductivity and 26.44% in interlaminar shear strength, making them promising thermal management laminated materials.
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http://dx.doi.org/10.1021/acsami.8b12691DOI Listing
November 2018

Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems.

Sensors (Basel) 2016 Mar 25;16(4):440. Epub 2016 Mar 25.

Institute of Optics and Electronics, Chinese Academy of Science, Chengdu 610209, China.

In a charge-coupled device (CCD)-based fast steering mirror (FSM) tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs) are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM) to realize the stabilization of the line-of-sight (LOS) of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.
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http://dx.doi.org/10.3390/s16040440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4850954PMC
March 2016

Metal-organic frameworks-derived synthesis of porous FeP nanocubes: an effective peroxidase mimetic.

J Colloid Interface Sci 2015 Dec 20;460:55-60. Epub 2015 Aug 20.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address:

Starting with metal-organic frameworks (MOFs), a facile process was demonstrated toward the synthesis of porous FeP nanocubes. Herein, Prussian blue nanocubes were used as iron-based MOFs precursors, and converted into FeP nanocubes through the thermal phosphidation reaction. Then, the FeP nanocubes were exploited as a peroxidase mimetic, which not only has the advantages of low cost, high stability, and easy preparation, but also follows Michaelis-Menten behaviors and shows strong affinity to substrates. On the basis of high catalytic activity of FeP nanocubes, a rapid, and convenient approach was developed for the colorimetric detection of H2O2 from 2μM to 130μM and with a detection limit of 0.62μM. The good catalytic activity and high stability make the porous FeP nanocubes a useful catalyst for a wide range of potential applications in catalysis and biotechnology.
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http://dx.doi.org/10.1016/j.jcis.2015.08.032DOI Listing
December 2015

Metal-organic frameworks derived CoxFe1-xP nanocubes for electrochemical hydrogen evolution.

Nanoscale 2015 Jul 5;7(25):11055-62. Epub 2015 Jun 5.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.

Designing and developing active, cost-effective and stable electrocatalysts for hydrogen evolution reaction (HER) are still an ongoing challenge. Herein, we report the synthesis of binary transition metal phosphide (CoxFe1-xP) nanocubes with different Co and Fe ratios through a phosphidation process using metal-organic frameworks (MOFs) as templates. MOF templates contribute well-defined nanocube architectural features after phosphidation, while a suitable phosphidation temperature could allow formation of a crystal structure and maintain the well-defined structure. The incorporation of a binary transition metal results in redistribution of the valence electrons in CoxFe1-xP. The changes imply anionic states of the P and Fe atoms, which act as active sites and thus have stronger electron-donating ability. When CoxFe1-xP nanocubes are employed as electrocatalysts, these characteristic features facilitate the performance of HER. Remarkably, Co0.59Fe0.41P nanocubes prepared at 450 °C afford a current density of 10 mA cm(-2) at a low overpotential of 72 mV in acidic conditions and 92 mV in alkaline conditions. Co0.59Fe0.41P nanocubes also exhibit a small Tafel slope of 52 mV decade(-1) in acidic conditions and 72 mV decade(-1) in alkaline conditions. Moreover, Co0.59Fe0.41P nanocubes show good stability in both acidic and alkaline conditions. Our method produces the highly active HER catalyst based on binary transition metal MOF templates, providing a new avenue for designing excellent electrocatalysts.
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http://dx.doi.org/10.1039/c5nr01955aDOI Listing
July 2015

Surfactant-assisted fabrication of 3D Prussian blue-reduced graphene oxide hydrogel as a self-propelling motor for water treatment.

Nanoscale 2015 Jun;7(23):10498-503

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.

Three-dimensional Prussian blue-reduced graphene oxide hydrogel was synthesized with the assistance of sodium dodecyl sulfate (SDS) through a facile hydrothermal method. The hydrogel exhibited strong mechanical properties and was successfully applied as a self-propelling motor for water treatment. During the self-propelling degradation process, SDS facilitated the rapid liberation of oxygen bubbles from the motor and the oxygen bubbles assisted the rapid diffusion of hydroxyl radicals. In addition, the well-defined structure increased the number of reaction sites and the synergy between reduced graphene oxide and Prussian blue, which accelerated the degradation efficiency. The self-propelling motor had an average velocity of 0.026 ± 0.013 cm s(-1) in 7.5% H2O2 and 0.069 ± 0.032 cm s(-1) in 22.5% H2O2. Moreover, the self-propelling motor maintained high degradation efficiency even after cycling for 9 times. These excellent properties make the self-propelling motor an ideal candidate for water treatment.
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http://dx.doi.org/10.1039/c5nr00759cDOI Listing
June 2015

Modifying candle soot with FeP nanoparticles into high-performance and cost-effective catalysts for the electrocatalytic hydrogen evolution reaction.

Nanoscale 2015 Mar;7(10):4400-5

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.

Developing inexpensive and highly efficient non-precious-metal electrocatalysts has been proposed as a promising alternative to platinum-based catalysts for the hydrogen evolution reaction (HER). Herein, we report novel FeP NPs supported on inexpensive and available candle soot (FeP-CS) derived from Fe3O4-CS hybrid precursors obtained after a phosphidation reaction. As HER electrocatalysts, the FeP-CS hybrids exhibit high electrocatalytic ability for HER with a Tafel slope of 58 mV dec(-1), a low onset overpotential of 38 mV, a large exchange current density of 2.2 × 10(-1) mA cm(-2) and an overpotential of 112 mV to obtain a current of 10 mA cm(-2). The present work shows significant advance in designing and developing non-precious-metal electrocatalysts for hydrogen evolution reaction.
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http://dx.doi.org/10.1039/c4nr07436jDOI Listing
March 2015

FeP nanoparticles grown on graphene sheets as highly active non-precious-metal electrocatalysts for hydrogen evolution reaction.

Chem Commun (Camb) 2014 Oct;50(78):11554-7

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.

A synthetic route to FeP-GS hybrid sheets that show good stability and high electrocatalytic activity for hydrogen evolution reaction is reported. The materials are prepared via thermal phosphidation of pre-synthesized Fe3O4-GS hybrid sheets.
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http://dx.doi.org/10.1039/c4cc05285dDOI Listing
October 2014

Facile synthesis of three dimensional hierarchical Co-Al layered double hydroxides on graphene as high-performance materials for supercapacitor electrode.

J Colloid Interface Sci 2014 Jul 12;426:131-6. Epub 2014 Apr 12.

State Key Laboratory of Electroanaytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address:

A facile simple hydrothermal method combined with a post-solution reaction is developed to grow interconnected three dimensional (3D) hierarchical Co-Al layered double hydroxides (LDHs) on reduced graphene oxide (rGO). The obtained 3D hierarchical rGO-LDHs are characterized by field emission scanning electron microscopy, X-ray diffraction, and X-ray photo-electron spectroscopy. As LDHs nanosheets directly grow on the surface of rGO via chemical covalent bonding, the rGO could provide facile electron transport paths in the electrode for the fast Faradaic reaction. Moreover, benefiting from the rational 3D hierarchical structural, the rGO-LDHs demonstrate excellent electrochemical properties with a combination of high charge storage capacitance, fast rate capability and stable cycling performance. Remarkably, the 3D hierarchical rGO-LDHs exhibit specific capacitance values of 599 F g(-1) at a constant current density of 4 A g(-1). The rGO-LDHs also show high charge-discharge reversibility with an efficiency of 92.4% after 5000 cycles.
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http://dx.doi.org/10.1016/j.jcis.2014.04.003DOI Listing
July 2014

One-pot solvothermal synthesis of graphene-supported TiO2 (B) nanosheets with enhanced lithium storage properties.

J Colloid Interface Sci 2013 Nov 2;409:38-42. Epub 2013 Aug 2.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.

A facile process was developed for the synthesis of graphene-supported TiO2 (B) nanosheets (GTBN) composite based on the hydrothermal treatment titanium (III) chloride and graphene oxide in an ethylene glycol. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy. The obtained GTBN show a high thermal stability and the phase transformation of TiO2 (B) to anatase can be prevented by graphene after pyrolysis of GTBN at 350°C for 2h. Furthermore, GTBN exhibited high rate performance and stability of lithium ion batteries, due to the enhanced conductivity of the electrode and accommodation to volume/strain changes during lithium insertion-extraction.
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http://dx.doi.org/10.1016/j.jcis.2013.07.053DOI Listing
November 2013

Porous Co₃O₄ nanorods-reduced graphene oxide with intrinsic peroxidase-like activity and catalysis in the degradation of methylene blue.

ACS Appl Mater Interfaces 2013 May 16;5(9):3809-15. Epub 2013 Apr 16.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.

A facile two step process was developed for the synthesis of porous Co3O4 nanorods-reduced graphene oxide (PCNG) hybrid materials based on the hydrothermal treatment cobalt acetate tetrahydrate and graphene oxide in a glycerol-water mixed solvent, followed by annealing the intermediate of reduced graphene oxide-supported Co(CO3)0.5(OH)·0.11H2O nanorods in a N2 atmosphere. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. It is shown that the obtained PCNG have intrinsic peroxidase-like activity. The PCNG are utilized for the catalytic degradation of methylene blue. The good catalytic performance of the composites could be attributed to the synergy between the functions of porous Co3O4 nanorods and reduced graphene oxide.
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http://dx.doi.org/10.1021/am4004655DOI Listing
May 2013

Hierarchical flower-like Co₃-xFexO₄ ferrite hollow spheres: facile synthesis and catalysis in the degradation of methylene blue.

Nanoscale 2013 Apr;5(7):3078-82

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.

A facile method is proposed for the synthesis of three-dimensional (3D) flower-like Co3-xFexO4 ferrite (CF) hollow spheres, using [email protected] as precursor. The CF hollow spheres are efficient for the catalytic degradation of methylene blue (MB) in the presence of H2O2 at 80 °C. The obtained CF hollow spheres were characterized using transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, and N2 adsorption-desorption isotherm measurements. The formation of 3D hierarchical flower-like superstructure was influenced by the relative amount of urea used. As the mole ratio of CoCl2 and urea decreased, the structure of the products was tailored from yolk-like spheres to hollow spheres with different sized void interiors. Moreover, N2 adsorption-desorption isotherm analysis showed that the CF hollow spheres have a large specific surface area (163 m(2) g(-1)) which provided more activity sites. The CF hollow spheres can catalyze the oxidation of MB efficiently. These results indicate that the designed CF hollow spheres exhibit promising capability for the degradation of dyes.
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http://dx.doi.org/10.1039/c3nr00041aDOI Listing
April 2013

Facile fabrication of SERS arrays through galvanic replacement of silver onto electrochemically deposited copper micropatterns.

Chemphyschem 2012 Dec 27;13(17):3786-9. Epub 2012 Sep 27.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China.

Scatter me: A fast and cost-effective approach for the fabrication of surface-enhanced Raman scattering (SERS) arrays is developed. The method applied combines microcontact printing, electrodeposition, and galvanic replacement without the need for expensive instruments and intricate processing. The as-prepared arrays show excellent SERS activity and high reproducibility for Rhodamine 6G.
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http://dx.doi.org/10.1002/cphc.201200525DOI Listing
December 2012

One-pot, solvothermal synthesis of TiO2-graphene composite nanosheets.

J Colloid Interface Sci 2012 Nov 7;386(1):198-204. Epub 2012 Aug 7.

State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.

In this article, we propose a facile one-pot solvothermal route for synthesizing TiO(2)-graphene composite nanosheets (TGCN). In the system, ethylene glycol not only as a reducing agent can convert graphene oxide to reduced graphene oxide nanosheets, but also is employed to control the hydrolysis and condensation rates of tetrabutoxytitanium. The obtained TGCN hybrid materials are characterized by atomic force microscopy, transmission electron microscopy, UV-vis spectroscopy, Raman spectroscopy, X-ray photo-electron spectroscopy, X-ray diffraction, and thermal gravimetric analysis. It is found that the quantity of H(2)O used in the reaction is the key to obtain high-quality product. The photocatalytic activities of the products are evaluated using the photocatalytic degradation of methylene blue (MB) as a probe reaction. The results showed that the obtained TGCN have an enhanced adsorption capacity and remarkable improvements in the photodegradation rate of MB under visible light compared to P25.
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http://dx.doi.org/10.1016/j.jcis.2012.07.068DOI Listing
November 2012

A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering.

Chem Commun (Camb) 2011 Jun 21;47(22):6440-2. Epub 2011 Apr 21.

State Key Laboratory of Electroanaytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.

Ag-graphene composite nanosheets (AGCN) with adjustable size and well-controlled densities of Ag nanoparticles (Ag NPs) using Poly(N-vinyl-2-pyrrolidone) (PVP) as a reductant and stabilizer are reported. The obtained AGCN substrate is extremely suitable for surface-enhanced Raman spectroscopy (SERS).
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http://dx.doi.org/10.1039/c1cc11125fDOI Listing
June 2011
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