Co-reporter:Hanwen Liu, Li Tao, Yiqiong Zhang, Chao Xie, Peng Zhou, Hongbo Liu, Ru Chen, and Shuangyin Wang
ACS Applied Materials & Interfaces October 25, 2017 Volume 9(Issue 42) pp:36849-36849
Publication Date(Web):October 5, 2017
DOI:10.1021/acsami.7b11599
Black phosphorus (BP) has recently aroused researchers’ great interest as promising anode material for sodium-ion battery (SIB), owing to its high theoretical capacity (2596 mAh g–1) and good electric conductivity (about 300 S m–1). However, the large volume variation during electrochemical cycling makes it difficult to use for practical applications. Herein, the reversible performance of BP in SIB is significantly enhanced by bridging covalently functionalized BP on graphene. The enhanced interaction between the chemical functionalized BP and graphene improves the stability of BP during long-cycle running of SIB. The bridging reduces the surface energy and increases thickness of BP available for enlarging the channel between BP nanosheet and graphene. The enlarged channel stores more sodium ions for improving cycle performance. Significantly, two types of phosphorus–carbon bond are first detected during experimental analysis. Benefiting from the strategy, the BP-based SIB anode exhibits 1472 mAh g–1 specific capacity at 0.1 A g–1 in the 50th cycle and 650 mAh g–1 at 1 A g–1 after 200 cycles.Keywords: anode; black phosphorus; chemical bonding; graphene; sodium-ion battery;
Co-reporter:Xiao Sun, Jia Huo, Yide Yang, Lei Xu, Shuangyin Wang
Journal of Energy Chemistry 2017 Volume 26, Issue 6(Volume 26, Issue 6) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.jechem.2017.05.006
The electrochemical hydrogen evolution reaction (HER) on a non-precious electrocatalyst in an alkaline environment is of essential importance for future renewable energy. The design of advanced electrocatalysts for HER is the most important part to reduce the cost and to enhance the efficiency of water splitting. MoS2 is considered as one of the most promising electrocatalysts to replace the precious Pt catalyst. Herein, for the first time, we have successfully loaded MoS2 electrocatalysts onto the Co3O4 nanosheet array to catalyze HER with a low onset potential of ∼76 mV. The high hydrogen evolution activity of MoS2 supported on the Co3O4 nanosheet array may be attributed to the increased active sites and the electronic interactions between MoS2 and Co3O4.Download high-res image (146KB)Download full-size imageWe put the Co3O4 nanosheets on the Ti Foil as a support, and then grow MoS2 on the support, thereby improving the hydrogen evolution reaction performance of MoS2.
Co-reporter:Li Tao, Chun-Yu Lin, Shuo Dou, Shi Feng, Dawei Chen, Dongdong Liu, Jia Huo, Zhenhai Xia, Shuangyin Wang
Nano Energy 2017 Volume 41(Volume 41) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.nanoen.2017.09.055
•Coordinatively unsaturated metal sites (CUMSs) in ZIF-67 were generated by plasma etching.•CUMSs has been demonstrated with high activity for OER.•The high OER activity induced by CUMSs is confirmed by the DFT calculation.Metal-organic-frameworks (MOFs), in which metal ions are single-atomically dispersed, are regarded as one of the most promising single-atom doped catalysts. Co-based species have been considered as a potential candidate to replace the precious RuO2 to electrocatalyze oxygen evolution reaction (OER). Zeolitic imidazolate frameworks-67 (ZIF-67), a Co-containing MOF, may be an excellent precursor for single-atom OER electrocatalysts due to its rich and uniform distribution of cobalt species. In principle, Co ions are fully coordinated (except for those on the surfaces) in ZIF-67 without accessible sites for electrocatalysis. One way to utilize this single-atom material as electrocatalysts is to remove some of the ligands attached to Co atoms to create coordinately unsaturated metal sites (CUMSs) as the catalytic centers for OER. Herein, we, for the first time, have created CUMSs in ZIF-67 through dielectric barrier discharge (DBD) plasma etching. The CUMSs act as excellent catalytic centers for OER with a promising electrocatalytic activity, even comparable to the precious RuO2. Interestingly, the OER activity of the CUMSs is reversible by supplementing the missing ligands. Our density-functional theory calculations also demonstrated the contribution of the unsaturated metal sites to the high catalytic activity for OER.Coordinatively Unsaturated Metal Sites (CUMSs) in ZIF-67 were formed through dielectric barrier discharge (DBD) plasma etching. The CUMSs act as excellent catalytic centers for OER with a promising electrocatalytic activity. Interestingly, the OER activity of the CUMSs is reversible by supplementing the missing ligands. Our density-functional theory calculations also demonstrated the contribution of the unsaturated metal sites to the high catalytic activity for OER.Download high-res image (214KB)Download full-size image
Co-reporter:Yuqing Huang, Qi Deng, Xiongwei Wu, Shuangyin Wang
International Journal of Hydrogen Energy 2017 Volume 42, Issue 10(Volume 42, Issue 10) pp:
Publication Date(Web):9 March 2017
DOI:10.1016/j.ijhydene.2016.04.004
•N,O co-doped graphite felt was successfully prepared by the plasma-assisted treatment.•The as-treated graphite was used as advanced electrodes for redox flow batteries.•The co-doping of N and O is of essential importance for the performance enhancement.We, for the first time, demonstrate a facile preparation of N, O dual-doped carbon felt (CF) as electrodes in all-vanadium redox flow batteries (VRFB). N2 and O2 plasma was employed to treat the CF, introducing nitrogen and oxygen atoms doped into the carbon felt to result in the improved electrocatalytic activity and enhanced interaction of CF-electrolyte during the battery operation. The energy efficiency of the as-assembled VRFB is improved from 65% (pristine) to 78% (doped) at a current density of 50 mA cm-2 with excellent cycling stability.Download high-res image (191KB)Download full-size image
Co-reporter:Kui Hu, Zhaohui Xiao, Yi Cheng, Dafeng Yan, Ru Chen, Jia Huo, Shuangyin Wang
Electrochimica Acta 2017 Volume 254(Volume 254) pp:
Publication Date(Web):10 November 2017
DOI:10.1016/j.electacta.2017.09.131
•FexP nanoparticles-decorated N, P-doped mesoporous carbon nanosheets electrocatalysts were prepared with a one-pot way.•The FexP/NPCS catalyst shows outstanding ORR performance over the whole pH range.•The FexP/NPCS holds superior durability.•This work broadens the application of iron phosphides in the field of electrocatalysis for fuel cell technologies.Developing electrocatalysts with both high activity and low cost for oxygen reduction reaction (ORR) has attracted much attention. Herein, we fabricated iron phosphide/N, P-doped carbon nanosheets electrocatalysts via a one-pot pyrolysis process without any post-treatments, which shows high ORR activity over the whole pH range. In alkaline solution, the optimal catalyst exhibits almost the same onset potential (0.918 V vs RHE) and half-wave potential (0.832 V vs RHE) with commercial Pt/C (20 wt %), meanwhile it shows prominent catalytic activity compared with Pt/C in acidic and neutral media. Noteworthy, the catalyst catalyzes ORR process following a one-step 4e pathway in all these media and poses better tolerance toward methanol and greater durability than Pt/C. It was proved that FexP (x = 1 or 2) and N, P-doped carbon synergistically contributed to the high ORR activity for the electrocatalysts. This work would broaden the application of iron phosphides in the field of electrocatalysis.Download high-res image (182KB)Download full-size image
Co-reporter:Dawei Chen;Chung-Li Dong;Yuqin Zou;Dong Su;Yu-Cheng Huang;Li Tao;Shuo Dou;Shaohua Shen
Nanoscale (2009-Present) 2017 vol. 9(Issue 33) pp:11969-11975
Publication Date(Web):2017/08/24
DOI:10.1039/C7NR04381C
Electrocatalytic water splitting is a key technique to produce hydrogen fuels, which can be considered as an efficient strategy to store renewable energy. Oxygen evolution reaction (OER) that occurs at the anode side requires a four-electron transfer under highly oxidizing conditions. OER has a large overpotential and therefore determines the overall efficiency. Certain electrocatalysts can efficiently help to improve the reaction kinetics. Owing to the high cost of precious metals such as Pt, Ru, and Ir, non-precious metal oxide catalysts have been vigorously investigated under alkaline conditions. Herein, we synthesized novel highly dispersed amorphous CoOxfor the first time in the form of a cluster favorable to enhance the OER activity using a facile method via the air dielectric barrier discharge (DBD) plasma. Compared with the pristine biopolymer–cobalt complex, the amorphous CoOx cluster exhibits a much higher current density and a lower overpotential for OER, e.g., the overpotential of 290 mV at 10 mA cm−2 and the overpotential of only 350 mV at 300 mA cm−1. The excellent electrocatalytic OER activity was attributed to the unsaturated catalytic sites on the amorphous CoOx cluster. In addition, we studied the reaction mechanism, and it was observed that pure O2 DBD plasma could lead to the evolution of crystalline CoOx; however, the presence of N2 and O2 in DBD plasma could ensure the facile evolution of amorphous CoOx clusters. This study provides a new strategy to design amorphous materials for electrocatalysis and beyond.
Co-reporter:Chao Xie;Yanyong Wang;Dafeng Yan;Li Tao
Nanoscale (2009-Present) 2017 vol. 9(Issue 41) pp:16059-16065
Publication Date(Web):2017/10/26
DOI:10.1039/C7NR06054H
Development of efficient non-noble metal electrocatalysts for oxygen evolution reaction (OER) is still a crucial issue for renewable energy technologies. Herein, we report a core–shell-like catalyst of amorphous cobalt borate nanosheets grown on metallic cobalt deposited on Ti-mesh (Co@Co–Bi/Ti) by an in situ conversion strategy. Benefiting from the high activity, large surface area of Co–Bi nanosheets, outstanding electronic conductivity of metallic Co and the 3D structure inherited from Ti-mesh substrate, Co@Co–Bi/Ti shows high OER activity with a relatively small overpotential of 329 mV to obtain a current density of 10 mA cm−2, a low Tafel slope of 46 mV dec−1 and an accessible large current density of 500 mA cm−2 in alkaline solution. Besides, Co@Co–Bi/Ti exhibits good performance in a near-neutral medium. This study provides an effective pathway to improve the cobalt metal based materials.
Co-reporter:Yiqiong Zhang;Zhaoling Ma;Dongdong Liu;Shuo Dou;Jianmin Ma;Ming Zhang;Zaiping Guo;Ru Chen
Journal of Materials Chemistry A 2017 vol. 5(Issue 2) pp:512-518
Publication Date(Web):2017/01/03
DOI:10.1039/C6TA09748K
In this work, for the first time, we have successfully constructed defective heterointerfaces of p-SnO on n-SnS2 nanosheets by plasma treatment to significantly improve Li+ and electron diffusion kinetics. The defective heterointerfaces show advanced electrochemical performance as the anode in Li-ion batteries.
Co-reporter:Zhaoling Ma;Li Tao;Dongdong Liu;Zhen Li;Yiqiong Zhang;Zhijuan Liu;Hanwen Liu;Ru Chen;Jia Huo
Journal of Materials Chemistry A 2017 vol. 5(Issue 19) pp:9412-9417
Publication Date(Web):2017/05/16
DOI:10.1039/C7TA01981E
The development of lithium–sulfur is impeded by two main obstacles: the dissolution of lithium polysulfides and the pristine insulation of sulfur. Here, high energy ball-milling with the assistance of dielectric barrier discharge plasma was used in synthesis of ultrafine sulfur particles anchored on in situ exfoliated graphene for Li–S batteries. The ultrafine sulfur particles formed not only afford more sufficient electrical contact towards graphene support, but also alleviate volume expansion compared with bulk sulfur. On the other hand, with robust etching function of dielectric barrier discharge plasma, little oxygen-doping was observed in exfoliated few-layer graphene, offering sufficient capture sites towards lithium polysulfides. The ultrafine sulfur/graphene composite with little oxygen-doping exhibits superior cycling performance and rate capability in contrast to the control samples without the exertion of dielectric barrier discharge plasma. Little capacity degradation rate of 0.07% per cycle was achieved at 0.5C over 500 cycles.
Co-reporter:Chao Xie;Yanyong Wang;Kui Hu;Li Tao;Xiaobing Huang;Jia Huo
Journal of Materials Chemistry A 2017 vol. 5(Issue 1) pp:87-91
Publication Date(Web):2016/12/20
DOI:10.1039/C6TA08149E
This work reports molybdenum oxide decorated NiFe alloy nanosheets with high OER activity by reducing MoO42− intercalated nickel–iron layered double hydroxides (LDHs). The presence of MoO42− successfully led to structural integrity, increase of active sites, and modification of the surface electronic properties of the NiFe alloy.
Co-reporter:Zhaohui Xiao;Yu Wang;Yu-Cheng Huang;Zengxi Wei;Chung-Li Dong;Jianmin Ma;Shaohua Shen;Yafei Li
Energy & Environmental Science (2008-Present) 2017 vol. 10(Issue 12) pp:2563-2569
Publication Date(Web):2017/12/06
DOI:10.1039/C7EE01917C
It is of essential importance to design an electrocatalyst with excellent performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. Co3O4 has been developed as a highly efficient OER electrocatalyst, but it has almost no activity for HER. In a previous study, it has been demonstrated that the formation of oxygen vacancies (VO) in Co3O4 can significantly enhance the OER activity. However, the stability of VO needs to be considered, especially under the highly oxidizing conditions of the OER process. It is a big challenge to stabilize the VO in Co3O4 while reserving the excellent activity. Filling the oxygen vacancies with heteroatoms in the VO-rich Co3O4 may be a smart strategy to stabilize the VO by compensating the coordination numbers and obtain an even surprising activity due to the modification of electronic properties by heteroatoms. Herein, we successfully transformed VO-rich Co3O4 into an HER-OER electrocatalyst by filling the in situ formed VO in Co3O4 with phosphorus (P-Co3O4) by treating Co3O4 with Ar plasma in the presence of a P precursor. The relatively lower coordination numbers in VO-Co3O4 than those in pristine Co3O4 were evidenced by X-ray adsorption spectroscopy, indicating that the oxygen vacancies were created after Ar plasma etching. On the other hand, the relatively higher coordination numbers in P-Co3O4 than those in VO-Co3O4 and nearly same coordination number as that in pristine Co3O4 strongly suggest the efficient filling of P in the vacancies by treatment with Ar plasma in the presence of a P precursor. The Co–O bonds in Co3O4 consist of octahedral Co3+(Oh)–O and tetrahedral Co2+(Td)–O (Oh, octahedral coordination by six oxygen atoms and Td, tetrahedral coordination by four oxygen atoms). More Co3+(Oh)–O are broken when oxygen vacancies are formed in VO-Co3O4, and more electrons enter the octahedral Co 3d orbital than those entering the tetrahedral Co 3d orbital. Then, with the filling of P in the vacancy site, electrons are transferred out of the Co 3d states, and more Co2+(Td) than Co3+(Oh) are left in P-Co3O4. These results suggest that the favored catalytic ability of P-Co3O4 is dominated by the Co2+(Td) site. P-Co3O4 shows superior electrocatalytic activities for HER and OER (among the best non-precious metal catalysts). Owing to its superior efficiency, P-Co3O4 can directly catalyze overall water splitting with excellent performance. The theoretical calculations illustrated that the improved electrical conductivity and intermediate binding by P-filling contributed significantly to the enhanced HER and OER activity of Co3O4.
Co-reporter:Yunxiao Li;Dafeng Yan;Yuqin Zou;Chao Xie;Yanyong Wang;Yiqiong Zhang
Journal of Materials Chemistry A 2017 vol. 5(Issue 48) pp:25494-25500
Publication Date(Web):2017/12/12
DOI:10.1039/C7TA08854J
The oxygen evolution reaction (OER) is one of the most important reactions in a wide range of renewable energy technologies. It is important to develop highly efficient electrocatalysts for the OER due to its sluggish kinetics. The electronic properties and morphological structure of electrocatalysts can significantly affect their OER performance. Electrocatalysts with the morphology of nanosheets can expose more active sites which would enhance the OER activity. Here, we report an extremely simple and fast method to synthesize a NixFe1−xSe@Ni(Fe)OOH core–shell nanostructure with a nanosheet shell by a facile solvothermal selenization and ion exchange reaction. The NixFe1−xSe@Ni(Fe)OOH core–shell nanostructure gives an excellent catalytic activity toward the OER with an overpotential as low as 260 mV to reach a current density of 100 mA cm−2 and excellent electrochemical long-term stability in 1 M KOH solution. The enhanced OER activity can be attributed to the dual modulation of electronic properties and the morphological structure by Fe doping.
Co-reporter:Yiqiong Zhang;Yanbing Lu;Shi Feng;Dongdong Liu;Zhaoling Ma
Journal of Materials Chemistry A 2017 vol. 5(Issue 43) pp:22512-22518
Publication Date(Web):2017/11/07
DOI:10.1039/C7TA08284C
Herein, we have successfully realized the on-site evolution of ultrafine ZnO nanoparticles from hollow zeolitic-imidazolate-framework-8 through a simple but efficient plasma treatment. With unique hollow frameworks which decorated with well-dispersed ultrafine ZnO nanoparticles, the h-ZIF-8@ZnO hybrids exhibit enhanced electrochemical performance for Li-ion batteries.
Co-reporter:Yanyong Wang;Yiqiong Zhang;Zhijuan Liu;Chao Xie;Shi Feng;Dongdong Liu; Mingfei Shao; Shuangyin Wang
Angewandte Chemie International Edition 2017 Volume 56(Issue 21) pp:5867-5871
Publication Date(Web):2017/05/15
DOI:10.1002/anie.201701477
AbstractLayered double hydroxides (LDHs) with two-dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).
Co-reporter:Yanyong Wang;Yiqiong Zhang;Zhijuan Liu;Chao Xie;Shi Feng;Dongdong Liu; Mingfei Shao; Shuangyin Wang
Angewandte Chemie 2017 Volume 129(Issue 21) pp:5961-5965
Publication Date(Web):2017/05/15
DOI:10.1002/ange.201701477
AbstractLayered double hydroxides (LDHs) with two-dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).
Co-reporter:Zhijuan Liu;Zhenghang Zhao;Yanyong Wang;Shuo Dou;Dafeng Yan;Dongdong Liu;Zhenhai Xia
Advanced Materials 2017 Volume 29(Issue 18) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/adma.201606207
Metal-free electrocatalysts have been extensively developed to replace noble metal Pt and RuO2 catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in fuel cells or metal–air batteries. These electrocatalysts are usually deposited on a 3D conductive support (e.g., carbon paper or carbon cloth (CC)) to facilitate mass and electron transport. For practical applications, it is desirable to create in situ catalysts on the carbon fiber support to simplify the fabrication process for catalytic electrodes. In this study, the first example of in situ exfoliated, edge-rich, oxygen-functionalized graphene on the surface of carbon fibers using Ar plasma treatment is successfully prepared. Compared to pristine CC, the plasma-etched carbon cloth (P-CC) has a higher specific surface area and an increased number of active sites for OER and ORR. P-CC also displays good intrinsic electron conductivity and excellent mass transport. Theoretical studies show that P-CC has a low overpotential that is comparable to Pt-based catalysts, as a result of both defects and oxygen doping. This study provides a simple and effective approach for producing highly active in situ catalysts on a carbon support for OER and ORR.
Co-reporter:Dafeng Yan;Yunxiao Li;Jia Huo;Ru Chen;Liming Dai
Advanced Materials 2017 Volume 29(Issue 48) pp:
Publication Date(Web):2017/12/01
DOI:10.1002/adma.201606459
AbstractOxygen electrocatalysis, including the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER), is a critical process for metal–air batteries. Therefore, the development of electrocatalysts for the OER and the ORR is of essential importance. Indeed, various advanced electrocatalysts have been designed for the ORR or the OER; however, the origin of the advanced activity of oxygen electrocatalysts is still somewhat controversial. The enhanced activity is usually attributed to the high surface areas, the unique facet structures, the enhanced conductivities, or even to unclear synergistic effects, but the importance of the defects, especially the intrinsic defects, is often neglected. More recently, the important role of defects in oxygen electrocatalysis has been demonstrated by several groups. To make the defect effect clearer, the recent development of this concept is reviewed here and a novel principle for the design of oxygen electrocatalysts is proposed. An overview of the defects in carbon-based, metal-free electrocatalysts for ORR and various defects in metal oxides/selenides for OER is also provided. The types of defects and controllable strategies to generate defects in electrocatalysts are presented, along with techniques to identify the defects. The defect–activity relationship is also explored by theoretical methods.
Co-reporter:Canbin Ouyang, Shi Feng, Jia Huo, Shuangyin Wang
Green Energy & Environment 2017 Volume 2, Issue 2(Volume 2, Issue 2) pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.gee.2017.01.004
Developing non-expensive, highly active and highly stable electrocatalysts for hydrogen evolution has aroused extensive attention, owing to the necessity of novel clean and sustainable energy carriers. In this paper, we report a synthesis of free-standing three-dimensional hierarchical MoS2/CoS2 heterostructure arrays through a convenient process. The investigation of electrocatalytic HER performance suggests that the MoS2/CoS2 hybrid catalyst exhibits significant enhancement in HER (onsetpotential and potential at a current density of 100 mA cm−2 are 20 mV and 125 mV, respectively) and superior durability (no shift of current density is observed after a continuous scanning of 3000 times) compared with individual CoS2 and MoS2. The superior HER performance was attributed to the formation of the interface between CoS2 and MoS2 through the electrochemical characterization, Raman, XPS analysis, and the control experiment. The lower onsetpotential, higher current density, excellent durability, and the free-standing structure of the three-dimensional hierarchical MoS2/CoS2 heterostructure array make it a promising cathode catalyst suitable for widespread application.Free-standing hierarchical MoS2/CoS2 heterostructure arrays were fabricated through a convenient process, which are highly active and stable as HER catalysts.Download high-res image (199KB)Download full-size image
Co-reporter:Shuo Dou, Li Tao, Jia Huo, Shuangyin Wang and Liming Dai
Energy & Environmental Science 2016 vol. 9(Issue 4) pp:1320-1326
Publication Date(Web):22 Jan 2016
DOI:10.1039/C6EE00054A
Highly efficient electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been regarded as the core elements in a wide range of renewable energy technologies. Surface engineering of the electrocatalysts is one of the most popular strategies to improve their catalytic activity. Herein, we, for the first time, designed an advanced bi-functional electrocatalyst for the ORR and OER by simultaneously etching and doping a cobalt sulfides–graphene hybrid with NH3-plasma. The graphene supported Co9S8 nanoparticles were prepared (denoted as Co9S8/G) first, followed by the NH3-plasma treatment, which could not only lead to nitrogen doping into both Co9S8 and graphene, but also partially etch the surface of both Co9S8 and graphene. The heteroatom doping could efficiently tune the electronic properties of Co9S8 and graphene, and the surface etching could expose more active sites for electrocatalysis, which can contribute significantly to the enhanced electrocatalytic performance for ORR and OER. The electrochemical results revealed that the etched and N-doped Co9S8/G shows excellent ORR activity, which is close to that of the commercial Pt/C catalyst, and great OER activity. The strategy developed here provides a novel and efficient approach to prepare hybrid bi-functional electrocatalysts for ORR and OER.
Co-reporter:Xin Wang, Xingyue Li, Canbin Ouyang, Zhen Li, Shuo Dou, Zhaoling Ma, Li Tao, Jia Huo and Shuangyin Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 24) pp:9370-9374
Publication Date(Web):23 May 2016
DOI:10.1039/C6TA03015G
In this work, we report the synthesis of mesoporous carbon derived from nonporous MOFs without any heteroatom doping or residual metal, which is highly efficient for the electrocatalytic oxygen reduction reaction. The excellent ORR activity is attributed to both high specific surface area and mesoporous structure.
Co-reporter:Shuo Dou, Xingyue Li, Li Tao, Jia Huo and Shuangyin Wang
Chemical Communications 2016 vol. 52(Issue 62) pp:9727-9730
Publication Date(Web):06 Jul 2016
DOI:10.1039/C6CC05244D
We successfully obtained a novel bi-functional electrocatalyst towards the ORR and OER: Co nanoparticle-embedded N-doped carbon nanotube (CNT)/porous carbon (PC) by pyrolyzing metal organic framework (MOF) encapsulated Co3O4. The as-obtained hybrid exhibited highly efficient electrocatalytic activity for the ORR and OER. Furthermore, the assembled Zn–air batteries also revealed promising performance and long-term stability.
Co-reporter:Qi-Min Gan, Li Tao, Lin-Nan Zhou, Xiao-Ting Zhang, Shuangyin Wang and Yong-Jun Li
Chemical Communications 2016 vol. 52(Issue 29) pp:5164-5166
Publication Date(Web):14 Mar 2016
DOI:10.1039/C6CC01391K
Ultralong (∼25–30 μm) surface-Pt-rich Au93Pt7 alloy nanowires (ANWs) were achieved by a directional coalescence between spherical nanoparticles. Also, the ANWs exhibit superior electrocatalytic activity and long-term durability towards ethanol oxidation, ∼12 times in the mass activity better than the state-of-the-art commercial Pt/C catalyst.
Co-reporter:Li Tao, Qiang Wang, Shuo Dou, Zhaoling Ma, Jia Huo, Shuangyin Wang and Liming Dai
Chemical Communications 2016 vol. 52(Issue 13) pp:2764-2767
Publication Date(Web):04 Jan 2016
DOI:10.1039/C5CC09173J
For the first time, we developed edge-rich and dopant-free graphene as a highly efficient ORR electrocatalyst. Electrochemical analysis revealed that the as-obtained edge-rich graphene showed excellent ORR activity through a one-step and four-electron pathway. With a similar strategy, edge-rich carbon nanotubes and graphite can also be obtained with enhanced ORR activity. This work confirms the important role of edge carbon in efficient ORR electrocatalysis without interruption by any other dopants.
Co-reporter:Kui Hu, Li Tao, Dongdong Liu, Jia Huo, and Shuangyin Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 30) pp:19379
Publication Date(Web):July 6, 2016
DOI:10.1021/acsami.6b02078
The high-temperature pyrolyzed Fe/N/C is one of the tremendous potential nonprecious metal electrocatalysts for oxygen reduction reaction (ORR). Metal-free carbon materials doped with heteroatoms have also demonstrated prominent electrocatalytic performance for ORR. The previous work of S-doping Fe/N/C was produced by pyrolyzing melamine and iron thiocyanate, in which S was from iron thiocyanate. Here, for the first time, we realized an in situ S-doping in Fe/N/C (denoted as S–Fe/N/C) electrocatalyst with S doping reaching 4.76 at % by pyrolyzing thiourea as the S source and iron acetate showing high-performance ORR activity in both alkaline and acid solution. The catalyst pyrolyzed at 700 °C and the mass ratio 1:0.2 shows the best activity for ORR. The optimal catalyst displays much greater durability and higher tolerance to methanol than Pt/C (20 wt %). Results of electrochemical measurements show that the S–Fe/N/C follows 4e pathway in alkaline and acid conditions.Keywords: doping; electrocatalyst; Fe/N/C; ORR; sulfur
Co-reporter:Zhaoling Ma, Zhen Li, Kui Hu, Dongdong Liu, Jia Huo, Shuangyin Wang
Journal of Power Sources 2016 Volume 325() pp:71-78
Publication Date(Web):1 September 2016
DOI:10.1016/j.jpowsour.2016.04.139
•Hierarchically porous CoS2/carbon paper as interlayer was used in LiS batteries.•CoS2/carbon paper interlayer traps the polysulfides.•A reversible capacity of 818 mAh g−1 at 0.2 C was retained after 200 cycles.The high-energy LiS battery suffers from poor cycling performance due to the shuttle effect of the polysulfides. Strategies must be adopted to suppress the diffusion of polysulfides into the electrolyte in LiS battery. In this work, for the first time, we adopt hydrophilic carbon paper anchored by hierarchically porous cobalt disulfides as the interlayer for capturing polysulfides through physical absorption and chemical bonding. Hierarchical pores can physically adsorb polysulfides, and moreover cobalt disulfide can trap the polysulfides by forming strong chemical interaction. The sulfur-graphene composite with a sulfur content of 70.5% delivers a high initial capacity of 1239.5 mAh g−1 at 0.2 C and retains a reversible capacity of 818 mAh g−1 after 200 cycles. In spite of a little capacity contribution by the insertion of lithium ions into cobalt disulfide for the initial cycles, it disappears in the subsequent cycling. Therefore, the as-developed porous transition metal disulfides on carbon paper as the interlayer could significantly enhance the cycling performance of LiS batteries.
Co-reporter:Qiuhong Liu, Jia Huo, Zhaoling Ma, Zhenjun Wu, Shuangyin Wang
Electrochimica Acta 2016 Volume 206() pp:52-60
Publication Date(Web):10 July 2016
DOI:10.1016/j.electacta.2016.04.121
•Ni3S2 interlayer was successfully in-situ formed between MoS2 and Ni foam by decomposing MoS2 precursors ((NH4)2MoS4) on Ni foam for the first time.•The presence of Ni3S2 interlayer significantly enhanced the stability and rate performance in lithium-ion batteries.•The interlayer strategy provides a novel principle for the design of durable and high-rate electrode materials in electrochemical energy storage devices.MoS2 has been extensively investigated as anode material in lithium-ion batteries (LIBs). However, the poor stability of MoS2 due to the weak interaction with conductive support and current collector significantly hinders its performance in LIBs. In this work, the Ni3S2 interlayer was successfully in-situ formed between MoS2 and Ni foam by decomposing MoS2 precurors ((NH4)2MoS4) on Ni foam (denoted as MoS2/Ni3S2/Ni). The presence of Ni3S2 interlayer significantly enhanced the interaction between MoS2 and Ni foam support, resulting in excellent stability in lithium-ion batteries. In addition, the foam structure facilitates the ion diffusion and electron transport properties of the electrode materials, leading to high-rate and highly durable performance. The as-prepared MoS2/Ni3S2/Ni reveals a capacity of 1263 mA hg−1 after 100 cycles at a current density of 0.1 Ag−1. On the other hand, it shows excellent rate performance, and it’s capacity can maintain at 740 mAh g−1 even at a high current density of 10 A g−1. The interlayer strategy provides a novel principle for the design of durable electrode materials in electrochemical energy storage devices. In this work, for the first time, the Ni3S2 interlayer was successfully in-situ formed between MoS2 and Ni foam by decomposing MoS2 precursors ((NH4)2MoS4) on Ni foam resulting in excellent performance in lithium-ion batteries. The interlayer strategy provides a novel principle for the design of electrode materials in electrochemical energy storage devices.
Co-reporter:Di Guo, Shuo Dou, Xiu Li, Jiantie Xu, Shuangyin Wang, Linfei Lai, Hua Kun Liu, Jianmin Ma, Shi Xue Dou
International Journal of Hydrogen Energy 2016 Volume 41(Issue 10) pp:5260-5268
Publication Date(Web):16 March 2016
DOI:10.1016/j.ijhydene.2016.01.070
•Hierarchical MnO2/rGO nanosheets as an efficient catalyst for ORR are fabricated.•The excellent catalytic activity is attributed to the synergetic effect.•Positive onset potential and high electron transfer number are demonstrated.Electrocatalysts for the oxygen reduction reaction (ORR) play a crucial role in renewable-energy technologies, including metal-air batteries and fuel cells. However, development of novel catalysts with high activity and low cost remains a great challenge. Here, we present hierarchical MnO2/reduced graphene oxide (MnO2/rGO) hybrid nanosheets by using a facile method and study its electrocatalytic performance. Cyclic voltammograms, and rotating disk electrode and rotating ring/disk electrode measurements demonstrate that the hierarchical MnO2/rGO hybrid nanosheets exhibit excellent electrocatalytic activity for the ORR in an alkaline medium, as evidenced by their higher cathodic current density, more positive onset potential, lower H2O2 yield, and higher electron transfer number compared to pure rGO. The excellent catalytic activity of the MnO2/rGO hybrid nanosheets highlights the importance of the synergetic chemical coupling effect between the ultrathin MnO2 nanosheets and the graphene layer.
Co-reporter:Lei Xu;Qianqian Jiang;Zhaohui Xiao;Xingyue Li;Jia Huo; Shuangyin Wang; Liming Dai
Angewandte Chemie 2016 Volume 128( Issue 17) pp:5363-5367
Publication Date(Web):
DOI:10.1002/ange.201600687
Abstract
Co3O4, which is of mixed valences Co2+ and Co3+, has been extensively investigated as an efficient electrocatalyst for the oxygen evolution reaction (OER). The proper control of Co2+/Co3+ ratio in Co3O4 could lead to modifications on its electronic and thus catalytic properties. Herein, we designed an efficient Co3O4-based OER electrocatalyst by a plasma-engraving strategy, which not only produced higher surface area, but also generated oxygen vacancies on Co3O4 surface with more Co2+ formed. The increased surface area ensures the Co3O4 has more sites for OER, and generated oxygen vacancies on Co3O4 surface improve the electronic conductivity and create more active defects for OER. Compared to pristine Co3O4, the engraved Co3O4 exhibits a much higher current density and a lower onset potential. The specific activity of the plasma-engraved Co3O4 nanosheets (0.055 mA cm−2BET at 1.6 V) is 10 times higher than that of pristine Co3O4, which is contributed by the surface oxygen vacancies.
Co-reporter:Lei Xu;Qianqian Jiang;Zhaohui Xiao;Xingyue Li;Jia Huo; Shuangyin Wang; Liming Dai
Angewandte Chemie International Edition 2016 Volume 55( Issue 17) pp:5277-5281
Publication Date(Web):
DOI:10.1002/anie.201600687
Abstract
Co3O4, which is of mixed valences Co2+ and Co3+, has been extensively investigated as an efficient electrocatalyst for the oxygen evolution reaction (OER). The proper control of Co2+/Co3+ ratio in Co3O4 could lead to modifications on its electronic and thus catalytic properties. Herein, we designed an efficient Co3O4-based OER electrocatalyst by a plasma-engraving strategy, which not only produced higher surface area, but also generated oxygen vacancies on Co3O4 surface with more Co2+ formed. The increased surface area ensures the Co3O4 has more sites for OER, and generated oxygen vacancies on Co3O4 surface improve the electronic conductivity and create more active defects for OER. Compared to pristine Co3O4, the engraved Co3O4 exhibits a much higher current density and a lower onset potential. The specific activity of the plasma-engraved Co3O4 nanosheets (0.055 mA cm−2BET at 1.6 V) is 10 times higher than that of pristine Co3O4, which is contributed by the surface oxygen vacancies.
Co-reporter:Canbin Ouyang, Xin Wang and Shuangyin Wang
Chemical Communications 2015 vol. 51(Issue 75) pp:14160-14163
Publication Date(Web):12 Aug 2015
DOI:10.1039/C5CC05541E
In this communication, we, for the first time, prepared phosphorus-doped cobalt disulfide nanosheets as highly advanced electrocatalysts for the hydrogen evolution reaction. It was demonstrated that P doping could significantly enhance the electrocatalytic performance of CoS2 nanosheets in terms of onset overpotential, Tafel slope, exchange current density, and stability.
Co-reporter:Lei Wang, Shuo Dou, Jiantie Xu, Hua Kun Liu, Shuangyin Wang, Jianmin Ma and Shi Xue Dou
Chemical Communications 2015 vol. 51(Issue 59) pp:11791-11794
Publication Date(Web):15 Jun 2015
DOI:10.1039/C5CC02973B
In this work, highly nitrogen doped carbon nanosheets (HNCNSs) have been successfully prepared by annealing EDTA calcium disodium salt. They exhibited a direct four-electron reaction pathway and high stability as an efficient metal-free catalyst for the oxygen reduction reaction.
Co-reporter:Li Tao, Xidong Duan, Chen Wang, Xiangfeng Duan and Shuangyin Wang
Chemical Communications 2015 vol. 51(Issue 35) pp:7470-7473
Publication Date(Web):25 Mar 2015
DOI:10.1039/C5CC01981H
Herein, for the first time, we reported a general approach of plasma engineering to tune the surface properties and edge reactive sites for greatly improving HER (hydrogen evolution) activity of MoS2. We show that the Ar or O2 plasma can be used to generate a large number of physical and chemical defects in 2D crystals to modify the electronic properties and increase the number of active sites in MoS2. Electrocatalytic studies show that the plasma-treated MoS2 exhibits significantly enhanced electrocatalytic activity for HER.
Co-reporter:Jiehua Liu, Anli Shen, Xiangfeng Wei, Kuan Zhou, Wei Chen, Fang Chen, Jiaqi Xu, Shuangyin Wang, and Liming Dai
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 37) pp:20507
Publication Date(Web):September 10, 2015
DOI:10.1021/acsami.5b07554
We describe the fabrication of ultrathin wrinkled N-doped carbon nanotubes by an in situ solid-state method. The positions of Co catalyst were first labeled by good-dispersion and highly loaded Au and Pt, indicating the most of Co are unsealed. The resultant unique nanoarchitecture, which exhibits the features of carbon nanotube and graphene with a combined effect of 1D and 2D carbon-based nanostructures, exhibited a superior ORR activity to carbon nanotubes and graphene. Moreover, the novel catalysts showed a better durability and higher tolerance to methanol crossover and poisoning effects than those of Pt/C.Keywords: electrocatalysis; fuel cells; non-noble catalysts; oxygen reduction reactions; synergistic effect; ultrathin carbon
Co-reporter:Qiuhong Liu, Zhenjun Wu, Zhaoling Ma, Shuo Dou, Jianghong Wu, Li Tao, Xin Wang, Canbing Ouyang, Anli Shen, Shuangyin Wang
Electrochimica Acta 2015 Volume 177() pp:298-303
Publication Date(Web):20 September 2015
DOI:10.1016/j.electacta.2015.01.193
•Nitrogen and sulfur co-doped graphene supported MoS2 nanosheets were successfully prepared and used as anode materials for Li-ion batteries.•The as-prepared anode materials show excellent stability in Li-ion batteries.•The materials show high reversible capacity for lithium ion batteries.Nitrogen and sulfur co-doped graphene supported MoS2 (MoS2/NS-G) nanosheets were prepared through a one-pot thermal annealing method. The as prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra and electrochemical techniques. The MoS2/NS-G shows high reversible capacity about 1200 mAh/g at current density of 150 mA/g and excellent stability in Li-ion batteries. It was demonstrated the co-doping of graphene by N and S could significantly enhance the durability of MoS2 as anode materials for Li-ion batteries.
Co-reporter:Li Tao, Shuo Dou, Zhaoling Ma, Shuangyin Wang
Electrochimica Acta 2015 Volume 157() pp:46-53
Publication Date(Web):1 March 2015
DOI:10.1016/j.electacta.2015.01.054
•Multiwalled carbon nanotube was functionalized with nitrobenzene as a support material for Pt-based electrocatalysts for methanol oxidation.•The electronic properties of carbon nanotubes were modified by the nitrobenzene functionalization.•Nitrobenzene-functionalized electrocatalysts revealing the improved electrocatalytic performance of Pt-NB-MWCNT catalyst for the methanol oxidation reaction.A novel method of molecular covalently functionalized multiwalled carbon nanotube using nitrobenzene group is prepared and used as a promising support material of Pt-based electrocatalysts (denoted as Pt-NB-MWCNT) for methanol oxidation reaction. The physical and chemical characteristics are performed by X-ray powder diffraction, transmission electron microscopy, Raman spectroscopy, thermogravimetric and X-ray photoelectron spectroscopy. The electrocatalytic are evaluated by cyclic voltammetry and chronoamperometry techniques. Compared with the un-functionalized Pt-MWCNT catalyst, Pt-NB-MWCNTs show more uniform particle dispersion, smaller particle size, improved activity and durability for methanol oxidation reaction. The nitrobenzene group is demonstrated to promote the electrocatalytic activity of Pt-MWCNT for methanol oxidation significantly. The results represent a novel approach to functionalize MWCNT in a simple and economic way to prepare efficient electrocatalysts for methanol oxidation.Multiwalled carbon nanotube was functionalized with nitrobenzene as a promising support material for Pt-based electrocatalysts (Pt-NB-MWCNT) for methanol oxidation. The as-prepared catalysts have higher electrocatalytic activity in terms of both mass and specific activities, and improved durability for methanol oxidation reaction than as compared to the undoped materials.
Co-reporter:Li Tao, Shuo Dou, Zhaoling Ma, Anli Shen, Shuangyin Wang
International Journal of Hydrogen Energy 2015 Volume 40(Issue 41) pp:14371-14377
Publication Date(Web):2 November 2015
DOI:10.1016/j.ijhydene.2015.02.104
•A method to synthesize Pt particles on nitrogen-doped graphene was presented.•The Pt/N-graphene shows a higher activity for methanol oxidation than Pt/graphene.•The role of nitrogen doping to promote the activity was discussed.Nitrogen doping could effectively enhance the catalytical activity of graphene-supported Pt nano-electrocatalysts for methanol oxidation reaction. Previously, the main strategy to the synthesis of Pt/N-graphene is the two-step reaction while it involves the complicated synthesis. In this work, we describe a facile and simple one-pot reaction including the reduction of graphene oxide, nitrogen doping of graphene, and uniform deposition of Pt nanoparticles on doped graphene. Compared with the Pt/graphene catalyst without nitrogen-doping, Pt/N-graphene exhibits excellent activity and durability towards methanol oxidation reaction, which is mainly ascribed to the contribution of the improved dispersion of Pt nanoparticles and the enhanced interaction between it and nitrogen-doped graphene. It is expected that this facile, green and economic single-step synthesis approach for the Pt/N-graphene electrocatalyst could be widely utilized to the nitrogen-doped graphene catalysts.In this work, we described a facile one-pot reaction for the simultaneous reduction of graphene oxide to graphene, nitrogen doping of graphene with urea, and deposition of Pt nanoparticles on doped graphene to prepare N-doped graphene supported Pt nano-electrocatalysts (Pt/N-graphene) for methanol oxidation. Compared with the updoped Pt/graphene catalyst, Pt/N-graphene presented excellent activity and durability towards methanol oxidation reaction contributed nitrogen doping.
Co-reporter:Zhen Li, Qianqian Jiang, Zhaoling Ma, Qiuhong Liu, Zhenjun Wu and Shuangyin Wang
RSC Advances 2015 vol. 5(Issue 97) pp:79473-79478
Publication Date(Web):14 Sep 2015
DOI:10.1039/C5RA17629H
To reduce the shuttle effect of lithium sulfur (Li–S) batteries and improve the cycling stability, the surface of the commercial separator in an Li–S battery was modified by the O2 plasma treatment, which generated lots of electronegative oxygenic functional groups such as –COOH and –OH on the surface of the separator. In order to confirm the existence and the effect of the electronegative oxygenic functional groups on the modified separator, the contact angle measurement and Fourier Transform Infrared Spectrometry (FTIR) were investigated. The charge/discharge and electrochemical impedance spectroscopy (EIS) tests of the Li–S battery assembled with the normal and the O2 plasma treated separator were analyzed. The surface characterization demonstrated that the oxygenic functional groups on the surface of the separator by the plasma modification played a critical role in improving the wettability and increasing electrical insulating properties. The cycling performance of Li–S batteries with the plasma treated separator had an obvious improvement owing to the electrostatic repulsion between electronegative oxygenic functional groups on the surface of O2 plasma treated separator and electronegative polysulfide. The battery assembled with O2 plasma treated separator had a higher capacity retention (48.53%) than that of the normal separator (24.51%).
Co-reporter:Qianqian Jiang, Lei Xu, Jia Huo, Han Zhang and Shuangyin Wang
RSC Advances 2015 vol. 5(Issue 92) pp:75145-75148
Publication Date(Web):28 Aug 2015
DOI:10.1039/C5RA14274A
We, for the first time, prepared layered Li(Ni1/3Co1/3Mn1/3)O2 by a novel oxygen plasma-assisted solid-state approach, which almost shows the best performance among ternary cathode materials for Li-ion batteries. More importantly, the developed strategy is time- and energy-saving, and thus promising for large-scale and cost-effective application.
Co-reporter:Qiuhong Liu, Zhenjun Wu, Jia Huo, Zhaoling Ma, Shuo Dou and Shuangyin Wang
RSC Advances 2015 vol. 5(Issue 90) pp:74012-74016
Publication Date(Web):26 Aug 2015
DOI:10.1039/C5RA14424H
We, for the first time, developed a SiO2-directed strategy for the surface control of hierarchical MoS2 microspheres as advanced anode materials for Li-ion batteries. The as-obtained MoS2 microspheres constructed with nanosheets show excellent battery performance, especially superior stability, due to their unique surface structure and extended interlayer distance of the nanosheets.
Co-reporter:Xin Wang, Canbin Ouyang, Shuo Dou, Dongdong Liu and Shuangyin Wang
RSC Advances 2015 vol. 5(Issue 52) pp:41901-41904
Publication Date(Web):01 May 2015
DOI:10.1039/C5RA05172J
An acid treatment can efficiently incorporate a large number of oxygen containing functional groups including –OH, –COOH, CO onto the surface of a carbon nanotube. These oxidized carbon nanotubes significantly improve the electrocatalytic activity towards the oxygen reduction reaction due to a more hydrophilic surface, more defect sites and the doping effect.
Co-reporter:Zhaoling Ma, Qiuhong Liu and Shuangyin Wang
RSC Advances 2015 vol. 5(Issue 3) pp:2096-2099
Publication Date(Web):19 Nov 2014
DOI:10.1039/C4RA13123A
Commercial Mo particles coated with an oxide layer of MoO3 were introduced into the sulfur-graphene cathode of Li–S battery. Mo particles in the core could improve the electronic conductivity of the electrode and MoO3 layer could alleviate polysulfides diffusion, which enhances the long life cycle. Note that the discharge capacity retention was 71.8% after 100 cycles at 0.1 C in the presence of 10 wt% Mo particles.
Co-reporter:Qianqian Jiang
The Journal of Physical Chemistry C 2015 Volume 119(Issue 52) pp:28776-28782
Publication Date(Web):December 14, 2015
DOI:10.1021/acs.jpcc.5b10298
Though considered as one of the most promising materials for rechargeable Li-ion batteries, spinel LiMn2O4 suffers from fast capacity fading during cycling due to the structural instability, Jahn–Teller distortion, and Mn dissolution into the electrolyte. In order to improve the electrochemical performance, in this work, we, for the first time, realize the sulfur doping by the plasma-assisted method in LiMn2O4. Physical properties of the synthesized materials LiMn2O4–xSx are measured by XRD, SEM, and EDS, which confirm that S atoms have been successfully doped into the structure of LiMn2O4 (LiMn2O4–xSx) with the high crystalline and uniform morphology. Compared to the pristine LiMn2O4 prepared by the conventional method (800 °C, 8 h), the LiMn2O4–xSx prepared by the plasma-assisted method shows superior performance with higher capacity (125.3 mAh·g–1) and significantly improved cycling stability (maintaining 97.76% of its initial discharge capacity after 60 cycles). In addition, the sulfur-doped LiMn2O4 demonstrates dramatically enhanced reversibility and stability even at the elevated temperature due to the improved structural stability and the suppressed Mn dissolution into the electrolyte by the doping of S. The sulfur doping into LiMn2O4 by the plasma-assisted method offers a new strategy for efficient modification of electrode materials for energy storage devices.
Co-reporter:Jianghong Wu, Shuo Dou, Anli Shen, Xin Wang, Zhaoling Ma, Canbin Ouyang and Shuangyin Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 48) pp:20990-20995
Publication Date(Web):28 Oct 2014
DOI:10.1039/C4TA05159A
In this work, for the first time, we have developed a one-step hydrothermal method to synthesize a hybrid material consisting of NiCo2S4 nanocrystals grown on reduced graphene oxide as an efficient nonprecious electrocatalyst for the oxygen reduction reaction (ORR) in alkaline medium. Our synthetic process here is quite simple, straightforward and environmentally benign. NiCo2S4–rGO shows significantly enhanced catalytic activity over rGO and NiCo2O4–rGO, and close reduction activity but much superior methanol tolerance and better durability than the commercial Pt/C catalyst. The half wave potential (E1/2) for the NiCo2S4–rGO hybrid is only about 62 mV more negative than that of the commercial Pt/C catalyst but 81 mV more positive than that of NiCo2O4–rGO, 116 mV than that of rGO. The superior performance of NiCo2S4–rGO is presumably attributed to a combination effect of mixed valence in transition metal composites favorable for O2 to be absorbed/reduced and a synergetic effect resulting from NiCo2S4 and rGO. The advantages over NiCo2O4–rGO might be ascribed to the inverse spinel crystal structure of NiCo2S4, its relative higher conductivity, and the fact that Na2S serves both as the S source and reducing agent facilitating an increase in the hybrid catalytic activity.
Co-reporter:Xin Wang, Jie Wang, Deli Wang, Shuo Dou, Zhaoling Ma, Jianghong Wu, Li Tao, Anli Shen, Canbin Ouyang, Qiuhong Liu and Shuangyin Wang
Chemical Communications 2014 vol. 50(Issue 37) pp:4839-4842
Publication Date(Web):18 Mar 2014
DOI:10.1039/C4CC00440J
Novel N, S co-doped graphene (NSG) was prepared by annealing graphene oxide with thiourea as the single N and S precursor. The NSG electrodes, as efficient metal-free electrocatalysts, show a direct four-electron reaction pathway, high onset potential, high current density and high stability for the oxygen reduction reaction.
Co-reporter:Shuo Dou, Anli Shen, Li Tao and Shuangyin Wang
Chemical Communications 2014 vol. 50(Issue 73) pp:10672-10675
Publication Date(Web):18 Jul 2014
DOI:10.1039/C4CC05055J
In this work, we successfully, for the first time, perform the molecular doping of graphene as metal-free electrocatalysts for oxygen reduction reaction. The doped small molecule onto graphene could induce the charge transfer between graphene and the molecules, which leads to significantly enhanced electrocatalytic activity for oxygen reduction reaction.
Co-reporter:Zhaoling Ma ; Xiaobing Huang ; Shuo Dou ; Jianghong Wu
The Journal of Physical Chemistry C 2014 Volume 118(Issue 31) pp:17231-17239
Publication Date(Web):July 8, 2014
DOI:10.1021/jp502226j
Fe2O3 supported on nitrogen-doped graphene (Fe2O3/N-rGO) hydrogel was prepared by a facial one-pot hydrothermal method. The efficient Fe2O3 loading and nitrogen doping of graphene was realized with this method. The morphology and structure of the samples were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, thermal gravimetric analysis, Raman spectra, X-ray diffraction, and nitrogen isothermal adsorption–desorption. The chemical environment of the surface composition of the samples was recorded by X-ray photoelectron spectroscopy. The electrochemical performance was tested with a three-electrode system in the aqueous electrolyte of 1 M KOH. The electrochemical measurement demonstrated that Fe2O3/N-rGO shows a specific capacitance as high as 618 F g–1 at a discharge current density of 0.5 A g–1. Even at the current density of 10 A g–1, the specific capacitance is still as high as 350 F g–1. After 5000 cycles, the capacity retention is still maintained at 56.7%.
Co-reporter:Anli Shen;Yuqin Zou; Qiang Wang; Robert A. W. Dryfe; Xiaobing Huang;Shuo Dou; Liming Dai; Shuangyin Wang
Angewandte Chemie International Edition 2014 Volume 53( Issue 40) pp:10804-10808
Publication Date(Web):
DOI:10.1002/anie.201406695
Abstract
Carbon-based metal-free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium have been extensively investigated with the aim of replacing the commercially available, but precious platinum-based catalysts. For the proper design of carbon-based metal-free electrocatalysts for the ORR, it would be interesting to identify the active sites of the electrocatalyst. The ORR was now studied with an air-saturated electrolyte solution droplet (diameter ca. 15 μm), which was deposited at a specified position either on the edge or on the basal plane of highly oriented pyrolytic graphite. Electrochemical measurements suggest that the edge carbon atoms are more active than the basal-plane ones for the ORR. This provides a direct way to identify the active sites of carbon materials for the ORR. Ball-milled graphite and carbon nanotubes with more exposed edges were also prepared and showed significantly enhanced ORR activity. DFT calculations elucidated the mechanism by which the charged edge carbon atoms result in the higher ORR activity.
Co-reporter:Yiqiong Zhang, Zhaoling Ma, Dongdong Liu, Shuo Dou, Jianmin Ma, Ming Zhang, Zaiping Guo, Ru Chen and Shuangyin Wang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 2) pp:NaN518-518
Publication Date(Web):2016/11/29
DOI:10.1039/C6TA09748K
In this work, for the first time, we have successfully constructed defective heterointerfaces of p-SnO on n-SnS2 nanosheets by plasma treatment to significantly improve Li+ and electron diffusion kinetics. The defective heterointerfaces show advanced electrochemical performance as the anode in Li-ion batteries.
Co-reporter:Li Tao, Xidong Duan, Chen Wang, Xiangfeng Duan and Shuangyin Wang
Chemical Communications 2015 - vol. 51(Issue 35) pp:NaN7473-7473
Publication Date(Web):2015/03/25
DOI:10.1039/C5CC01981H
Herein, for the first time, we reported a general approach of plasma engineering to tune the surface properties and edge reactive sites for greatly improving HER (hydrogen evolution) activity of MoS2. We show that the Ar or O2 plasma can be used to generate a large number of physical and chemical defects in 2D crystals to modify the electronic properties and increase the number of active sites in MoS2. Electrocatalytic studies show that the plasma-treated MoS2 exhibits significantly enhanced electrocatalytic activity for HER.
Co-reporter:Canbin Ouyang, Xin Wang and Shuangyin Wang
Chemical Communications 2015 - vol. 51(Issue 75) pp:NaN14163-14163
Publication Date(Web):2015/08/12
DOI:10.1039/C5CC05541E
In this communication, we, for the first time, prepared phosphorus-doped cobalt disulfide nanosheets as highly advanced electrocatalysts for the hydrogen evolution reaction. It was demonstrated that P doping could significantly enhance the electrocatalytic performance of CoS2 nanosheets in terms of onset overpotential, Tafel slope, exchange current density, and stability.
Co-reporter:Xin Wang, Jie Wang, Deli Wang, Shuo Dou, Zhaoling Ma, Jianghong Wu, Li Tao, Anli Shen, Canbin Ouyang, Qiuhong Liu and Shuangyin Wang
Chemical Communications 2014 - vol. 50(Issue 37) pp:NaN4842-4842
Publication Date(Web):2014/03/18
DOI:10.1039/C4CC00440J
Novel N, S co-doped graphene (NSG) was prepared by annealing graphene oxide with thiourea as the single N and S precursor. The NSG electrodes, as efficient metal-free electrocatalysts, show a direct four-electron reaction pathway, high onset potential, high current density and high stability for the oxygen reduction reaction.
Co-reporter:Jianghong Wu, Shuo Dou, Anli Shen, Xin Wang, Zhaoling Ma, Canbin Ouyang and Shuangyin Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 48) pp:NaN20995-20995
Publication Date(Web):2014/10/28
DOI:10.1039/C4TA05159A
In this work, for the first time, we have developed a one-step hydrothermal method to synthesize a hybrid material consisting of NiCo2S4 nanocrystals grown on reduced graphene oxide as an efficient nonprecious electrocatalyst for the oxygen reduction reaction (ORR) in alkaline medium. Our synthetic process here is quite simple, straightforward and environmentally benign. NiCo2S4–rGO shows significantly enhanced catalytic activity over rGO and NiCo2O4–rGO, and close reduction activity but much superior methanol tolerance and better durability than the commercial Pt/C catalyst. The half wave potential (E1/2) for the NiCo2S4–rGO hybrid is only about 62 mV more negative than that of the commercial Pt/C catalyst but 81 mV more positive than that of NiCo2O4–rGO, 116 mV than that of rGO. The superior performance of NiCo2S4–rGO is presumably attributed to a combination effect of mixed valence in transition metal composites favorable for O2 to be absorbed/reduced and a synergetic effect resulting from NiCo2S4 and rGO. The advantages over NiCo2O4–rGO might be ascribed to the inverse spinel crystal structure of NiCo2S4, its relative higher conductivity, and the fact that Na2S serves both as the S source and reducing agent facilitating an increase in the hybrid catalytic activity.
Co-reporter:Xin Wang, Xingyue Li, Canbin Ouyang, Zhen Li, Shuo Dou, Zhaoling Ma, Li Tao, Jia Huo and Shuangyin Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 24) pp:NaN9374-9374
Publication Date(Web):2016/05/23
DOI:10.1039/C6TA03015G
In this work, we report the synthesis of mesoporous carbon derived from nonporous MOFs without any heteroatom doping or residual metal, which is highly efficient for the electrocatalytic oxygen reduction reaction. The excellent ORR activity is attributed to both high specific surface area and mesoporous structure.
Co-reporter:Shuo Dou, Anli Shen, Li Tao and Shuangyin Wang
Chemical Communications 2014 - vol. 50(Issue 73) pp:NaN10675-10675
Publication Date(Web):2014/07/18
DOI:10.1039/C4CC05055J
In this work, we successfully, for the first time, perform the molecular doping of graphene as metal-free electrocatalysts for oxygen reduction reaction. The doped small molecule onto graphene could induce the charge transfer between graphene and the molecules, which leads to significantly enhanced electrocatalytic activity for oxygen reduction reaction.
Co-reporter:Lei Wang, Shuo Dou, Jiantie Xu, Hua Kun Liu, Shuangyin Wang, Jianmin Ma and Shi Xue Dou
Chemical Communications 2015 - vol. 51(Issue 59) pp:NaN11794-11794
Publication Date(Web):2015/06/15
DOI:10.1039/C5CC02973B
In this work, highly nitrogen doped carbon nanosheets (HNCNSs) have been successfully prepared by annealing EDTA calcium disodium salt. They exhibited a direct four-electron reaction pathway and high stability as an efficient metal-free catalyst for the oxygen reduction reaction.
Co-reporter:Shuo Dou, Xingyue Li, Li Tao, Jia Huo and Shuangyin Wang
Chemical Communications 2016 - vol. 52(Issue 62) pp:NaN9730-9730
Publication Date(Web):2016/07/06
DOI:10.1039/C6CC05244D
We successfully obtained a novel bi-functional electrocatalyst towards the ORR and OER: Co nanoparticle-embedded N-doped carbon nanotube (CNT)/porous carbon (PC) by pyrolyzing metal organic framework (MOF) encapsulated Co3O4. The as-obtained hybrid exhibited highly efficient electrocatalytic activity for the ORR and OER. Furthermore, the assembled Zn–air batteries also revealed promising performance and long-term stability.
Co-reporter:Qi-Min Gan, Li Tao, Lin-Nan Zhou, Xiao-Ting Zhang, Shuangyin Wang and Yong-Jun Li
Chemical Communications 2016 - vol. 52(Issue 29) pp:NaN5166-5166
Publication Date(Web):2016/03/14
DOI:10.1039/C6CC01391K
Ultralong (∼25–30 μm) surface-Pt-rich Au93Pt7 alloy nanowires (ANWs) were achieved by a directional coalescence between spherical nanoparticles. Also, the ANWs exhibit superior electrocatalytic activity and long-term durability towards ethanol oxidation, ∼12 times in the mass activity better than the state-of-the-art commercial Pt/C catalyst.
Co-reporter:Li Tao, Qiang Wang, Shuo Dou, Zhaoling Ma, Jia Huo, Shuangyin Wang and Liming Dai
Chemical Communications 2016 - vol. 52(Issue 13) pp:NaN2767-2767
Publication Date(Web):2016/01/04
DOI:10.1039/C5CC09173J
For the first time, we developed edge-rich and dopant-free graphene as a highly efficient ORR electrocatalyst. Electrochemical analysis revealed that the as-obtained edge-rich graphene showed excellent ORR activity through a one-step and four-electron pathway. With a similar strategy, edge-rich carbon nanotubes and graphite can also be obtained with enhanced ORR activity. This work confirms the important role of edge carbon in efficient ORR electrocatalysis without interruption by any other dopants.
Co-reporter:Chao Xie, Yanyong Wang, Kui Hu, Li Tao, Xiaobing Huang, Jia Huo and Shuangyin Wang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 1) pp:NaN91-91
Publication Date(Web):2016/11/21
DOI:10.1039/C6TA08149E
This work reports molybdenum oxide decorated NiFe alloy nanosheets with high OER activity by reducing MoO42− intercalated nickel–iron layered double hydroxides (LDHs). The presence of MoO42− successfully led to structural integrity, increase of active sites, and modification of the surface electronic properties of the NiFe alloy.
Co-reporter:Zhaohui Xiao, Xiaobing Huang, Lei Xu, Dafeng Yan, Jia Huo and Shuangyin Wang
Chemical Communications 2016 - vol. 52(Issue 88) pp:NaN13011-13011
Publication Date(Web):2016/10/07
DOI:10.1039/C6CC07217H
The development of efficient, stable and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is the key for water splitting. Carbon-based nanomaterials have found significant applications as metal-free OER electrocatalysts. In this study, for the first time, edge-selectively phosphorus-doped graphene (G–P) was synthesised for OER electrocatalysts. The G–P catalyst reached a current density of 10 mA cm−2 at a small overpotential of 330 mV for the OER with a Tafel slope as low as 62 mV dec−1, which is superior to most of the carbon-based electrocatalysts reported to date.
Co-reporter:Dafeng Yan, Shuo Dou, Li Tao, Zhijuan Liu, Zhigang Liu, Jia Huo and Shuangyin Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 36) pp:NaN13730-13730
Publication Date(Web):2016/07/28
DOI:10.1039/C6TA05863A
In this work, for the first time, we report the synthesis of N, P co-doped carbon derived from electrochemically polymerized supermolecules. The as-obtained N, P co-doped carbon fiber networks show ultra-efficient HER activity as a metal-free electrocatalyst with an overpotential of 151 mV to reach a current density of 10 mA cm−2.
Co-reporter:Zhaoling Ma, Li Tao, Dongdong Liu, Zhen Li, Yiqiong Zhang, Zhijuan Liu, Hanwen Liu, Ru Chen, Jia Huo and Shuangyin Wang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 19) pp:NaN9417-9417
Publication Date(Web):2017/04/13
DOI:10.1039/C7TA01981E
The development of lithium–sulfur is impeded by two main obstacles: the dissolution of lithium polysulfides and the pristine insulation of sulfur. Here, high energy ball-milling with the assistance of dielectric barrier discharge plasma was used in synthesis of ultrafine sulfur particles anchored on in situ exfoliated graphene for Li–S batteries. The ultrafine sulfur particles formed not only afford more sufficient electrical contact towards graphene support, but also alleviate volume expansion compared with bulk sulfur. On the other hand, with robust etching function of dielectric barrier discharge plasma, little oxygen-doping was observed in exfoliated few-layer graphene, offering sufficient capture sites towards lithium polysulfides. The ultrafine sulfur/graphene composite with little oxygen-doping exhibits superior cycling performance and rate capability in contrast to the control samples without the exertion of dielectric barrier discharge plasma. Little capacity degradation rate of 0.07% per cycle was achieved at 0.5C over 500 cycles.
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