Publications by authors named "Chuangang Hu"

44 Publications

Understanding of catalytic ROS generation from defect-rich graphene quantum-dots for therapeutic effects in tumor microenvironment.

J Nanobiotechnology 2021 Oct 26;19(1):340. Epub 2021 Oct 26.

Australian Carbon Materials Centre (A-CMC), School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.

Owing to their low cost, high catalytic efficiency and biocompatibility, carbon-based metal-free catalysts (C-MFCs) have attracted intense interest for various applications, ranging from energy through environmental to biomedical technologies. While considerable effort and progress have been made in mechanistic understanding of C-MFCs for non-biomedical applications, their catalytic mechanism for therapeutic effects has rarely been investigated. In this study, defect-rich graphene quantum dots (GQDs) were developed as C-MFCs for efficient ROS generation, specifically in the HO-rich tumor microenvironment to cause multi-level damages of subcellular components (even in nuclei). While a desirable anti-cancer performance was achieved, the catalytic performance was found to strongly depend on the defect density. It is for the first time that the defect-induced catalytic generation of ROS by C-MFCs in the tumor microenvironment was demonstrated and the associated catalytic mechanism was elucidated. This work opens a new avenue for the development of safe and efficient catalytic nanomedicine.
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http://dx.doi.org/10.1186/s12951-021-01053-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8547047PMC
October 2021

Carbon-based metal-free electrocatalysts: from oxygen reduction to multifunctional electrocatalysis.

Chem Soc Rev 2021 Nov 1;50(21):11785-11843. Epub 2021 Nov 1.

Australian Carbon Materials Centre (A-CMC), School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia.

Since the discovery of N-doped carbon nanotubes as the first carbon-based metal-free electrocatalyst (C-MFEC) for oxygen reduction reaction (ORR) in 2009, C-MFECs have shown multifunctional electrocatalytic activities for many reactions beyond ORR, such as oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CORR), nitrogen reduction reaction (NRR), and hydrogen peroxide production reaction (HOPR). Consequently, C-MFECs have attracted a great deal of interest for various applications, including metal-air batteries, water splitting devices, regenerative fuel cells, solar cells, fuel and chemical production, water purification, to mention a few. By altering the electronic configuration and/or modulating their spin angular momentum, both heteroatom(s) doping and structural defects (, atomic vacancy, edge) have been demonstrated to create catalytic active sites in the skeleton of graphitic carbon materials. Although certain C-MFECs have been made to be comparable to or even better than their counterparts based on noble metals, transition metals and/or their hybrids, further research and development are necessary in order to translate C-MFECs for practical applications. In this article, we present a timely and comprehensive, but critical, review on recent advancements in the field of C-MFECs within the past five years or so by discussing various types of electrocatalytic reactions catalyzed by C-MFECs. An emphasis is given to potential applications of C-MFECs for energy conversion and storage. The structure-property relationship for and mechanistic understanding of C-MFECs will also be discussed, along with the current challenges and future perspectives.
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http://dx.doi.org/10.1039/d1cs00219hDOI Listing
November 2021

High-Performance, Long-Life, Rechargeable Li-CO Batteries based on a 3D Holey Graphene Cathode Implanted with Single Iron Atoms.

Adv Mater 2020 Apr 28;32(16):e1907436. Epub 2020 Feb 28.

Center of Advanced Science and Engineering for Carbon (Case4carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

A highly efficient cathode catalyst for rechargeable Li-CO batteries is successfully synthesized by implanting single iron atoms into 3D porous carbon architectures, consisting of interconnected N,S-codoped holey graphene (HG) sheets. The unique porous 3D hierarchical architecture of the catalyst with a large surface area and sufficient space within the interconnected HG framework can not only facilitate electron transport and CO /Li diffusion, but also allow for a high uptake of Li CO to ensure a high capacity. Consequently, the resultant rechargeable Li-CO batteries exhibit a low potential gap of ≈1.17 V at 100 mA g and can be repeatedly charged and discharged for over 200 cycles with a cut-off capacity of 1000 mAh g at a high current density of 1 A g . Density functional theory calculations are performed and the observed appealing catalytic performance is correlated with the hierarchical structure of the carbon catalyst. This work provides an effective approach to the development of highly efficient cathode catalysts for metal-CO batteries and beyond.
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http://dx.doi.org/10.1002/adma.201907436DOI Listing
April 2020

Carbon-Defect-Driven Electroless Deposition of Pt Atomic Clusters for Highly Efficient Hydrogen Evolution.

J Am Chem Soc 2020 Mar 13;142(12):5594-5601. Epub 2020 Mar 13.

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Sciences and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States.

Pt atomic clusters (Pt-ACs) display outstanding electrocatalytic performance because of their unique electronic structure with a large number of highly exposed surface atoms. However, the small size and large specific surface area intrinsically associated with ACs pose challenges in the synthesis and stabilization of Pt-ACs without agglomeration. Herein, we report a novel one-step carbon-defect-driven electroless deposition method to produce ultrasmall but well-defined and stable Pt-ACs supported by defective graphene (Pt-AC/DG) structures. A theoretical simulation clearly revealed that the defective regions with a lower work function and hence a higher reducing capacity compared to those of normal hexagonal sites triggered the reduction of Pt ions preferentially at the defect sites. Moreover, the strong binding energy between Pt and carbon defects effectively restricted the migration of spontaneously reduced Pt atoms to immobilize/stabilize the resultant Pt-ACs. Electrochemical analyses demonstrated the high performance of Pt-ACs in catalyzing the hydrogen evolution reaction, showing a greatly enhanced mass activity, a high Pt utilization efficiency, and excellent stability compared with commercial Pt/C catalysts. The integration of proton exchange membrane water electrolysis with Pt-AC/DG as a cathode exhibited an excellent hydrogen generation activity and extraordinary stability (during 200 h of electrolysis) with a greatly reduced Pt usage compared with commercial Pt/C catalysts.
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http://dx.doi.org/10.1021/jacs.9b11524DOI Listing
March 2020

High-Performance K-CO Batteries Based on Metal-Free Carbon Electrocatalysts.

Angew Chem Int Ed Engl 2020 Feb 29;59(9):3470-3474. Epub 2020 Jan 29.

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Metal-CO batteries have attracted much attention owing to their high energy density and use of greenhouse CO waste as the energy source. However, the increasing cost of lithium and the low discharge potential of Na-CO batteries create obstacles for practical applications of Li/Na-CO batteries. Recently, earth-abundant potassium ions have attracted considerable interest as fast ionic charge carriers for electrochemical energy storage. Herein, we report the first K-CO battery with a carbon-based metal-free electrocatalyst. The battery shows a higher theoretical discharge potential (E =2.48 V) than that of Na-CO batteries (E =2.35 V) and can operate for more than 250 cycles (1500 h) with a cutoff capacity of 300 mA h g . Combined DFT calculations and experimental observations revealed a reaction mechanism involving the reversible formation and decomposition of P12 /c1-type K CO at the efficient carbon-based catalyst.
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http://dx.doi.org/10.1002/anie.201913687DOI Listing
February 2020

Carbon Nanomaterials for Energy and Biorelated Catalysis: Recent Advances and Looking Forward.

ACS Cent Sci 2019 Mar 8;5(3):389-408. Epub 2019 Feb 8.

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University (CWRU), 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.

Along with the wide investigation activities in developing carbon-based, metal-free catalysts to replace precious metal (e.g., Pt) catalysts for various green energy devices, carbon nanomaterials have also shown great potential for biorelated applications. This article provides a focused, critical review on the recent advances in these emerging research areas. The structure-property relationship and mechanistic understanding of recently developed carbon-based, metal-free catalysts for chemical/biocatalytic reactions will be discussed along with the challenges and perspectives in this exciting field, providing a look forward for the rational design and fabrication of new carbon-based, metal-free catalysts with high activities, remarkable selectivity, and outstanding durability for various energy-related/biocatalytic processes.
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http://dx.doi.org/10.1021/acscentsci.8b00714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6439526PMC
March 2019

Carbon-Based Metal-Free Catalysts for Energy Storage and Environmental Remediation.

Adv Mater 2019 Mar 28;31(13):e1806128. Epub 2019 Jan 28.

Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Owing to their high earth-abundance, eco-friendliness, high electrical conductivity, large surface area, structure tunability at the atomic/morphological levels, and excellent stability in harsh conditions, carbon-based metal-free materials have become promising advanced electrode materials for high-performance pseudocapacitors and metal-air batteries. Furthermore, carbon-based nanomaterials with well-defined structures can function as green catalysts because of their efficiency in advanced oxidation processes to remove organics in air or from water, which reduces the cost for air/water purification and avoids cross-contamination by eliminating the release of heavy metals/metal ions. Here, the research and development of carbon-based catalysts in supercapacitors and batteries for clean energy storage as well as in air/water treatments for environmental remediation are reviewed. The related mechanistic understanding and design principles of carbon-based metal-free catalysts are illustrated, along with the challenges and perspectives in this emerging field.
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http://dx.doi.org/10.1002/adma.201806128DOI Listing
March 2019

Doping of Carbon Materials for Metal-Free Electrocatalysis.

Adv Mater 2019 Feb 19;31(7):e1804672. Epub 2018 Dec 19.

Center of Advanced Science and Engineering for Carbon (Case4carbon), Department of Macromolecule Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Carbon atoms in the graphitic carbon skeleton can be replaced by heteroatoms with different electronegative from that of the carbon atom (i.e., heteroatom doping) to modulate the charge distribution over the carbon network. The charge modulation can be achieved via direct charge transfer with an electron acceptor/donor (i.e., charge transfer doping) or through introduction of defects (i.e., defective doping). Various doping strategies, including heteroatom doping, charge-transfer doping, and defective doping, have now been devised for modulating the charge distribution of numerous graphite carbon materials to impart new properties to carbon materials. Consequently, carbon nanomaterials with defined doping have recently become prominent members in the carbon family, promising for a variety of applications, including catalysis, energy conversion and storage, environmental remediation, and important chemical production and industrial processes. The purpose of this review is to present an overview on the doping of carbon materials for metal-free electrocatalysis, especially the development of doping strategies and doping-induced structure and property changes for potential catalytic applications. Current challenges and future perspectives in the doped carbon-based metal-free catalyst field are also discussed.
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http://dx.doi.org/10.1002/adma.201804672DOI Listing
February 2019

Microporous N,P-Codoped Graphitic Nanosheets as an Efficient Electrocatalyst for Oxygen Reduction in Whole pH Range for Energy Conversion and Biosensing Dissolved Oxygen.

Chemistry 2018 Dec 7;24(69):18487-18493. Epub 2018 Aug 7.

Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang, 325027, China.

Microporous N,P-codoped graphitic nanosheets (N,P-CMP-1000) were synthesized by thermal annealing (1000 °C) of as-synthesized conjugated microporous polymers (CMPs) in the presence of phytic acid, which can be used as an effective metal-free electrocatalyst for the oxygen reduction reaction (ORR) for energy conversion. In the whole pH range (i.e. alkaline, acidic, and neutral solutions), the obtained N,P-CMP-1000 exhibits superior electrocatalytic activity for ORR with a low overpotential, high current density, and good stability. Furthermore, N,P-CMP-1000 can also be applied for electrochemically sensing dissolved oxygen (DO), with a high sensitivity (1.89 μA mg  L) and broad detection range (2.56 to 16.65 mg L ) due to its good electrocatalytic performance towards ORR in neutral solution. In vitro cytotoxicity tests (CCK-8 and Live/Dead Cell Double Staining Assay) of N,P-CMP-1000 extracts demonstrated its good biocompatibility to Human Corneal Epithelial Cells (HCEC), which shows its great potential as an eye-wearable biosensor for sensing DO in tears.
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http://dx.doi.org/10.1002/chem.201802040DOI Listing
December 2018

Chronic interfacing with the autonomic nervous system using carbon nanotube (CNT) yarn electrodes.

Sci Rep 2017 09 15;7(1):11723. Epub 2017 Sep 15.

Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106-7078, USA.

The ability to reliably and safely communicate chronically with small diameter (100-300 µm) autonomic nerves could have a significant impact in fundamental biomedical research and clinical applications. However, this ability has remained elusive with existing neural interface technologies. Here we show a new chronic nerve interface using highly flexible materials with axon-like dimensions. The interface was implemented with carbon nanotube (CNT) yarn electrodes to chronically record neural activity from two separate autonomic nerves: the glossopharyngeal and vagus nerves. The recorded neural signals maintain a high signal-to-noise ratio (>10 dB) in chronic implant models. We further demonstrate the ability to process the neural activity to detect hypoxic and gastric extension events from the glossopharyngeal and vagus nerves, respectively. These results establish a novel, chronic platform neural interfacing technique with the autonomic nervous system and demonstrate the possibility of regulating internal organ function, leading to new bioelectronic therapies and patient health monitoring.
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http://dx.doi.org/10.1038/s41598-017-10639-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5601469PMC
September 2017

Multifunctional Carbon-Based Metal-Free Electrocatalysts for Simultaneous Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution.

Adv Mater 2017 Mar 23;29(9). Epub 2016 Dec 23.

Center of Advanced Science and Engineering for Carbon (Case 4carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Rationally designed N, S co-doped graphitic sheets with stereoscopic holes (SHG) act as effective tri-functional catalysts for the oxygen reduction reaction, hydrogen evolution reaction, and oxygen evolution reaction, simultaneously. The multifunctional electrocatalytic activities originate from a synergistic effect of the N, S heteroatom doping and unique SHG architecture, which provide a large surface area and efficient pathways for electron and electrolyte/reactant transports.
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http://dx.doi.org/10.1002/adma.201604942DOI Listing
March 2017

Functionalized carbon nanotubes and graphene-based materials for energy storage.

Chem Commun (Camb) 2016 Dec;52(100):14350-14360

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.

Carbon nanotubes (CNTs) or graphene-based nanomaterials functionalized by different strategies have attracted great attention for energy storage due to their large specific surface area, high conductivity, and good mechanical properties. This feature article presents an overview of the recent progress in the functionalization of CNTs and graphene-based materials for energy storage applications in supercapacitors and batteries, along with challenges and perspectives in this exciting field.
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http://dx.doi.org/10.1039/c6cc05581hDOI Listing
December 2016

Carbon-Based Metal-Free Catalysts for Electrocatalysis beyond the ORR.

Angew Chem Int Ed Engl 2016 09 27;55(39):11736-58. Epub 2016 Jul 27.

Center of Advanced Science and Engineering for Carbon (Case4carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Besides their use in fuel cells for energy conversion through the oxygen reduction reaction (ORR), carbon-based metal-free catalysts have also been demonstrated to be promising alternatives to noble-metal/metal oxide catalysts for the oxygen evolution reaction (OER) in metal-air batteries for energy storage and for the splitting of water to produce hydrogen fuels through the hydrogen evolution reaction (HER). This Review focuses on recent progress in the development of carbon-based metal-free catalysts for the OER and HER, along with challenges and perspectives in the emerging field of metal-free electrocatalysis.
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http://dx.doi.org/10.1002/anie.201509982DOI Listing
September 2016

Spontaneous, Straightforward Fabrication of Partially Reduced Graphene Oxide-Polypyrrole Composite Films for Versatile Actuators.

ACS Nano 2016 04 29;10(4):4735-41. Epub 2016 Mar 29.

Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry, Beijing Institute of Technology , Beijing 100081, P. R. China.

A facile one-step approach has been developed to fabricate partially reduced graphene oxide-polypyrrole (prGO-PPy) film via self-oxidation-reduction strategy, in which graphene oxide acts as the oxidant to polymerize pyrrole into PPy leading to the spontaneous partial reduction of GO and cross-linking between prGO and PPy via π-π interaction. With the convenient preparation method, a well controlled designed asymmetric actuator based on GO (or G)/prGO-PPy film with excellent humidity and electrochemical responses has been achieved for versatile stimulated actuations that will also play essential roles in advanced actuators for many important intelligent applications.
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http://dx.doi.org/10.1021/acsnano.6b01233DOI Listing
April 2016

A General and Extremely Simple Remote Approach toward Graphene Bulks with In Situ Multifunctionalization.

Adv Mater 2016 05 2;28(17):3305-12. Epub 2016 Mar 2.

Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing, 100081, P. R. China.

Functional graphene bulks are developed by a general and simple approach for largescale preparation. This method shows promise for energy-related applications.
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http://dx.doi.org/10.1002/adma.201505431DOI Listing
May 2016

Scalable Preparation of Multifunctional Fire-Retardant Ultralight Graphene Foams.

ACS Nano 2016 Jan 13;10(1):1325-32. Epub 2016 Jan 13.

Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case School of Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States.

Traditional flame-retardant materials often show poor tolerance to oxidants, strong acidic/alkaline reagents, organic solvents, along with toxicity problems. Herein, highly fire-retardant ultralight graphene foam has been developed, which possesses not only ultralight and compressible characteristics but also efficient flame-retardant properties, outperforming those traditional polymer, metallic oxide, and metal hydroxide based flame retardant materials and their composites. The newly developed unconventional refractory materials are promising for specific applications as demonstrated by the observed high temperature resistant microwave absorption capability.
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http://dx.doi.org/10.1021/acsnano.5b06710DOI Listing
January 2016

One-pot Synthesis of Nitrogen and Phosphorus Co-doped Graphene and Its Use as High-performance Electrocatalyst for Oxygen Reduction Reaction.

Chem Asian J 2015 Dec 21;10(12):2609-14. Epub 2015 Sep 21.

Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectric/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology.

In this study, N,P co-doped graphene (NPG) was prepared by a one-step pyrolysis using a mixture of graphene oxide and hexachlorocyclotriphosphazene (HCCP), in which HCCP was used as both the N and P source. Furthermore, it is shown that NPG electrodes, as efficient metal-free electrocatalysts, have a high onset potential, high current density, and long-term stability for the oxygen reduction reaction.
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http://dx.doi.org/10.1002/asia.201500707DOI Listing
December 2015

A Graphitic-C3N4 "Seaweed" Architecture for Enhanced Hydrogen Evolution.

Angew Chem Int Ed Engl 2015 Sep 15;54(39):11433-7. Epub 2015 Jul 15.

Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijng 100081 (P.R. China).

A seaweed-like graphitic-C3N4 (g-C3N4 "seaweed") architecture has been prepared by direct calcination of the freeze-drying-assembled, hydrothermally treated dicyandiamide fiber network. The seaweed network of mesoporous g-C3N4 nanofibers is favorable for light harvesting, charge separation and utilization of active sites, and has highly efficient photocatalytic behavior for water splitting. It exhibits a high hydrogen-evolution rate of 9900 μmol h(-1) g(-1) (thirty times higher than that of its g-C3N4 bulk counterpart), and a remarkable apparent quantum efficiency of 7.8% at 420 nm, better than most of the g-C3N4 nanostructures reported. This work presents a very simple method for designing and developing high-performance catalysts for hydrogen evolution.
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http://dx.doi.org/10.1002/anie.201504985DOI Listing
September 2015

Supramolecular quantum dots as biodegradable nano-probes for upconversion-enabled bioimaging.

Chem Commun (Camb) 2015 Aug;51(67):13201-4

Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081, P. R. China.

We report the biodegradable supramolecular quantum dots (SQDs) of hydrogen-bonded graphitic carbon nitride (g-C3N4) with low cytotoxicity and desirable biocompatibility for promising upconversion-enabled fluorescent bio-probes. A remarkable biodegradation of up to 97% within 24 hours is presented.
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http://dx.doi.org/10.1039/c5cc04831aDOI Listing
August 2015

Re-shaping graphene hydrogels for effectively enhancing actuation responses.

Nanoscale 2015 Aug 1;7(29):12372-8. Epub 2015 Jul 1.

Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectric/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

The development of actuation-enabled materials is important for smart devices and systems. Among them, graphene with outstanding electric, thermal, and mechanical properties holds great promise as a new type of stimuli-responsive material. In this study, we developed a re-shaping strategy to construct structure-controlled graphene hydrogels for highly enhanced actuation responses. Actuators based on the re-shaped graphene hydrogel showed a much higher actuation response than that of the common graphene counterparts. On the other hand, once composited with a conducting polymer (e.g., polypyrrole), the re-shaped hybrid actuator exhibits excellent actuation behavior in response to electrochemical potential variation. Even under stimulation at a voltage as low as 0.8 V, actuators based on the re-shaped graphene-polypyrrole composite hydrogel exhibit a maximum strain response of up to 13.5%, which is the highest value reported to date for graphene-based materials.
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http://dx.doi.org/10.1039/c5nr02604kDOI Listing
August 2015

Spontaneous formation of Cu2O-g-C3N4 core-shell nanowires for photocurrent and humidity responses.

Nanoscale 2015 Jun;7(21):9694-702

Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

The assembly of low dimensional g-C3N4 structures in a geometrically well-defined fashion and the complexation of g-C3N4 with other materials are the main approaches to construct fancy structures for special functions. While high temperature was often indispensable for the preparation process, the realization of room temperature assembly of the low dimensional g-C3N4 and the preparation of g-C3N4-based semiconductor composites will provide many additional advantages for new functional materials and applications. Herein, the unique cuprous oxide (Cu2O)-graphitic carbon nitrides (g-C3N4) core-shell nanowires with highly hierarchical sharp edges on the surface have been prepared by a spontaneous reduction and assembly approach based on oxygen-functional g-C3N4 (O-functional g-C3N4) at room temperature. Combined with the hybrid effect of Cu2O with g-C3N4, such hierarchical Cu2O-g-C3N4 core-shell nanowires possess sensitivity to humidity and photocurrent response.
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http://dx.doi.org/10.1039/c5nr01521aDOI Listing
June 2015

Monoatomic-thick graphitic carbon nitride dots on graphene sheets as an efficient catalyst in the oxygen reduction reaction.

Nanoscale 2015 Feb;7(7):3035-42

Key Laboratory of Cluster Science, Ministry of Education of China Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, Beijing 100081, P. R. China.

Atomically thick two-dimensional materials have been increasingly attracting research interest not only due to their promising applications in a range of functional devices but also to their theoretical value to unraveling the catalytic electron transfer process within a simplified scenario. In this work, the monoatomic-thick dot-sized graphitic carbon nitride (g-C3N4) has been synthesized and intimately contacted to the basal plane of the graphene sheet to form the monolayer g-C3N4 [email protected] (MTCG). The electrocatalytic activity of the MTCG in the oxygen reduction reaction is found to rival that of the commercial Pt/C catalyst in terms of the catalytic current density and half-wave potential. The density functional theory calculations confirm the catalytic improvement of the MTCG originates from a higher efficiency for the reduction of OOH(-) than that of the g-C3N4 alone; therefore, the current work is expected to provide new insights in developing next-generation, highly efficient catalysts for the oxygen reduction reaction.
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http://dx.doi.org/10.1039/c4nr05343eDOI Listing
February 2015

Uniquely arranged graphene-on-graphene structure as a binder-free anode for high-performance lithium-ion batteries.

Small 2014 Dec 8;10(24):5035-41. Epub 2014 Aug 8.

Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing, 100081, P.R. China.

3D graphene interconnected frameworks homogeneously connected with a few-layer graphene film (3DG/FLG) constitute a novel hierarchical hybrid structure for anodes in lithium-ion batteries. The pore-rich 3D graphene network is favorable for Li(+) diffusion and electron transport, and the FLG is a non-metallic current collector that effectively collects/transports charge carriers from/to the 3D graphene network and provides an excellent scaffold to support the 3DG.
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http://dx.doi.org/10.1002/smll.201401610DOI Listing
December 2014

Graphene quantum dots-three-dimensional graphene composites for high-performance supercapacitors.

Phys Chem Chem Phys 2014 Sep;16(36):19307-13

Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

Graphene quantum dots (GQDs) have been successfully deposited onto the three-dimensional graphene (3DG) by a benign electrochemical method and the ordered 3DG structure remains intact after the uniform deposition of GQDs. In addition, the capacitive properties of the as-formed GQD-3DG composites are evaluated in symmetrical supercapacitors. It is found that the supercapacitor fabricated from the GQD-3DG composite is highly stable and exhibits a high specific capacitance of 268 F g(-1), representing a more than 90% improvement over that of the supercapacitor made from pure 3DG electrodes (136 F g(-1)). Owing to the convenience of the current method, it can be further used in other well-defined electrode materials, such as carbon nanotubes, carbon aerogels and conjugated polymers to improve the performance of the supercapacitors.
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http://dx.doi.org/10.1039/c4cp02761bDOI Listing
September 2014

Designing nitrogen-enriched echinus-like carbon capsules for highly efficient oxygen reduction reaction and lithium ion storage.

Nanoscale 2014 Jul;6(14):8002-9

Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectric/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, Beijing 100081, P. R. China.

Both structural and compositional modulations are important for high-performance electrode materials in energy conversion/storage devices. Here hierarchical-structure nitrogen-rich hybrid porous carbon capsules with bamboo-like carbon nanotube whiskers ([email protected]) grown in situ have been specifically designed, which combine the advantageous features of high surface area, abundant active sites, easy access to medium and favorable mass transport. As a result, the newly prepared [email protected] show highly efficient catalytic activity in oxygen reduction reaction in alkaline media for fuel cells, which not only outperforms commercial Pt-based catalysts in terms of kinetic limiting current, stability and tolerance to methanol crossover effect, but is also better than most of the nanostructured carbon-based catalysts reported previously. On the other hand, as an anode material for lithium ion batteries, the [email protected] obtained also exhibit an excellent reversible capacity of ca. 1337 mA h g(-1) at 0.5 A g(-1), outstanding rate capability and long cycling stability, even at a current density of 20 A g(-1). The capacity is the highest among all the heteroatom-doped carbon materials reported so far, and is even higher than that of many of the composites of metal, metal oxides or metal sulfides with carbon materials.
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http://dx.doi.org/10.1039/c4nr01184hDOI Listing
July 2014

Small-sized PdCu nanocapsules on 3D graphene for high-performance ethanol oxidation.

Nanoscale 2014 Mar 27;6(5):2768-75. Epub 2014 Jan 27.

Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectric/Electrophotonic Conversion Materials, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

A one-pot solvothermal process has been developed for direct preparation of PdCu nanocapsules (with a size of ca. 10 nm) on three-dimensional (3D) graphene. Due to the 3D pore-rich network of graphene and the unique hollow structure of PdCu nanocapsules with a wall thickness of ca. 3 nm, the newly-prepared PdCu/3D graphene hybrids activated electrochemically have great electrocatalytic activity towards ethanol oxidation in alkaline media, much better than single-phase Pd and commercial E-TEK 20% Pt/C catalysts promising for application in direct ethanol fuel cells.
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http://dx.doi.org/10.1039/c3nr05722dDOI Listing
March 2014

Three-dimensional macroporous NiCo(2)O(4) sheets as a non-noble catalyst for efficient oxygen reduction reactions.

Chemistry 2013 Oct 5;19(42):14271-8. Epub 2013 Sep 5.

Department of Chemistry, Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Institute of Technology, Beijing 100081 (P.R. China).

A facile and low-cost strategy is developed to prepare three-dimensional (3D) macroporous NiCo2 O4 sheets, which can be used as a highly efficient non-noble metal electrocatalyst for the oxygen reduction reaction (ORR) in alkaline conditions. The as-obtained sheets have a thickness of about 150 nm and feature a typical 3D macroporous structure with pore volumes of up to 0.23 cm(3)  g(-1) , which could decrease the mass transport resistance and allow easier access of the reactants to the active surface sites. The as-prepared macroporous NiCo2 O4 sheets exhibit high electrocatalytic activity for ORR with a four-electron pathway, good long-term stability and high tolerance against methanol. The unique 3D macroporous structure and intrinsic properties may be responsible for their high performance.
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http://dx.doi.org/10.1002/chem.201302193DOI Listing
October 2013

Graphene fibers with predetermined deformation as moisture-triggered actuators and robots.

Angew Chem Int Ed Engl 2013 Sep 14;52(40):10482-6. Epub 2013 Aug 14.

Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing Key Laboratory of Photoelectric/Electrophotonic Conversion Materials, Beijing 100081 (China) http://sc.bit.edu.cn/kyjgjktz/qltktz/index.htm.

Enough to make your hair curl! Moisture-responsive graphene (G) fibers can be prepared by the positioned laser reduction of graphene oxide (GO) counterparts. When exposed to moisture, the asymmetric G/GO fibers display complex, well-controlled motion/deformation in a predetermined manner. These fibers can function not only as a single-fiber walking robot under humidity alternation but also as a new platform for woven devices and smart textiles.
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http://dx.doi.org/10.1002/anie.201304358DOI Listing
September 2013

3D graphene-Fe3O4 nanocomposites with high-performance microwave absorption.

Phys Chem Chem Phys 2013 Aug;15(31):13038-43

Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

3D Fe3O4-graphene nanocomposites were conveniently prepared via a direct hydrothermal grafting method. On the basis of the unique properties of both single-crystalline Fe3O4 and 3D chemically reduced graphene oxide, with characteristics such as ultralow density and high surface area, the as-prepared graphene-Fe3O4 nanocomposites showed high-performance microwave absorption ability and have the potential for application as advanced microwave absorbers.
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http://dx.doi.org/10.1039/c3cp51253cDOI Listing
August 2013

Spontaneous reduction and assembly of graphene oxide into three-dimensional graphene network on arbitrary conductive substrates.

Sci Rep 2013 ;3:2065

Key Laboratory of Cluster Science, Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.

Chemical reduction of graphene oxide (GO) is the main route to produce the mass graphene-based materials with tailored surface chemistry and functions. However, the toxic reducing circumstances, multiple steps, and even incomplete removal of the oxygen-containing groups were involved, and the produced graphenes existed usually as the assembly-absent precipitates. Herein, a substrate-assisted reduction and assembly of GO (SARA-GO) method was developed for spontaneous formation of 3D graphene network on arbitrary conductive substrates including active and inert metals, semiconducting Si, nonmetallic carbon, and even indium-tin oxide glass without any additional reducing agents. The SARA-GO process offers a facile, efficient approach for constructing unique graphene assemblies such as microtubes, multi-channel networks, micropatterns, and allows the fabrication of high-performance binder-free rechargeable lithium-ion batteries. The versatile SARD-GO method significantly improves the processablity of graphenes, which could thus benefit many important applications in sensors and energy-related devices.
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http://dx.doi.org/10.1038/srep02065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3691888PMC
October 2013
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