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1.
Synergistic Phase and Disorder Engineering in 1T‐MoSe2 Nanosheets for Enhanced Hydrogen‐Evolution Reaction
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Ying Yin Yumin Zhang Tangling Gao Tai Yao Xinghong Zhang Jiecai Han Xianjie Wang Zhihua Zhang Ping Xu Peng Zhang Xingzhong Cao Bo Song Song Jin 《Advanced materials (Deerfield Beach, Fla.)》2017,29(28)
MoSe2 is a promising earth‐abundant electrocatalyst for the hydrogen‐evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX2) materials than MoS2 so far. Here, a novel hydrothermal‐synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T‐MoSe2 nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH4 reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites. Such synergistic effects lead to superior HER catalytic activity with an overpotential of 152 mV versus reversible hydrogen electrode (RHE) for the electrocatalytic current density of j = ?10 mA cm?2, and a Tafel slope of 52 mV dec?1. This work paves a new pathway for improving the catalytic activity of MoSe2 and generally MX2‐based electrocatalysts via a synergistic modulation strategy. 相似文献
2.
Phase Modulation of (1T‐2H)‐MoSe2/TiC‐C Shell/Core Arrays via Nitrogen Doping for Highly Efficient Hydrogen Evolution Reaction
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Shengjue Deng Fan Yang Qinghua Zhang Yu Zhong Yinxiang Zeng Shiwei Lin Xiuli Wang Xihong Lu Cai‐Zhuang Wang Lin Gu Xinhui Xia Jiangping Tu 《Advanced materials (Deerfield Beach, Fla.)》2018,30(34)
Tailoring molybdenum selenide electrocatalysts with tunable phase and morphology is of great importance for advancement of hydrogen evolution reaction (HER). In this work, phase‐ and morphology‐modulated N‐doped MoSe2/TiC‐C shell/core arrays through a facile hydrothermal and postannealing treatment strategy are reported. Highly conductive TiC‐C nanorod arrays serve as the backbone for MoSe2 nanosheets to form high‐quality MoSe2/TiC‐C shell/core arrays. Impressively, continuous phase modulation of MoSe2 is realized on the MoSe2/TiC‐C arrays. Except for the pure 1T‐MoSe2 and 2H‐MoSe2, mixed (1T‐2H)‐MoSe2 nanosheets are achieved in the N‐MoSe2 by N doping and demonstrated by spherical aberration electron microscope. Plausible mechanism of phase transformation and different doping sites of N atom are proposed via theoretical calculation. The much smaller energy barrier, longer H? Se bond length, and diminished bandgap endow N‐MoSe2/TiC‐C arrays with substantially superior HER performance compared to 1T and 2H phase counterparts. Impressively, the designed N‐MoSe2/TiC‐C arrays exhibit a low overpotential of 137 mV at a large current density of 100 mA cm?2, and a small Tafel slope of 32 mV dec?1. Our results pave the way to unravel the enhancement mechanism of HER on 2D transition metal dichalcogenides by N doping. 相似文献
3.
Bionanofiber Assisted Decoration of Few‐Layered MoSe2 Nanosheets on 3D Conductive Networks for Efficient Hydrogen Evolution
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Feili Lai Dingyu Yong Xueliang Ning Bicai Pan Yue‐E Miao Tianxi Liu 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Molybdenum diselenide (MoSe2) has emerged as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its properties are still confined due to the limited active sites and poor conductivity. Thus, it remains a great challenge to synergistically achieve structural and electronic modulations for MoSe2‐based HER catalysts because of the contradictory relationship between these two characteristics. Herein, bacterial cellulose‐derived carbon nanofibers are used to assist the uniform growth of few‐layered MoSe2 nanosheets, which effectively increase the active sites of MoSe2 for hydrogen atom adsorption. Meanwhile, carbonized bacterial cellulose (CBC) nanofibers provide a 3D network for electrolyte penetration into the inner space and accelerate electron transfer as well, thus leading to the dramatically increased HER activity. In acidic media, the CBC/MoSe2 hybrid catalyst exhibits fast hydrogen evolution kinetics with onset overpotential of 91 mV and Tafel slope of 55 mV dec?1, which is much more outstanding than both bulk MoSe2 aggregates and CBC nanofibers. Furthermore, the fast HER kinetics are well supported by theoretical calculations of density‐functional‐theory analysis with a low activation barrier of 0.08 eV for H2 generation. Hence, this work highlights an efficient solution to develop high‐performance HER catalysts by incorporating biotemplate materials, to simultaneously achieve increased active sites and conductivity. 相似文献
4.
Preparation of High‐Percentage 1T‐Phase Transition Metal Dichalcogenide Nanodots for Electrochemical Hydrogen Evolution
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Chaoliang Tan Zhimin Luo Apoorva Chaturvedi Yongqing Cai Yonghua Du Yue Gong Ying Huang Zhuangchai Lai Xiao Zhang Lirong Zheng Xiaoying Qi Min Hao Goh Jie Wang Shikui Han Xue‐Jun Wu Lin Gu Christian Kloc Hua Zhang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(9)
Nanostructured transition metal dichalcogenides (TMDs) are proven to be efficient and robust earth‐abundant electrocatalysts to potentially replace precious platinum‐based catalysts for the hydrogen evolution reaction (HER). However, the catalytic efficiency of reported TMD catalysts is still limited by their low‐density active sites, low conductivity, and/or uncleaned surface. Herein, a general and facile method is reported for high‐yield, large‐scale production of water‐dispersed, ultrasmall‐sized, high‐percentage 1T‐phase, single‐layer TMD nanodots with high‐density active edge sites and clean surface, including MoS2, WS2, MoSe2, Mo0.5W0.5S2, and MoSSe, which exhibit much enhanced electrochemical HER performances as compared to their corresponding nanosheets. Impressively, the obtained MoSSe nanodots achieve a low overpotential of ?140 mV at current density of 10 mA cm?2, a Tafel slope of 40 mV dec?1, and excellent long‐term durability. The experimental and theoretical results suggest that the excellent catalytic activity of MoSSe nanodots is attributed to the high‐density active edge sites, high‐percentage metallic 1T phase, alloying effect and basal‐plane Se‐vacancy. This work provides a universal and effective way toward the synthesis of TMD nanostructures with abundant active sites for electrocatalysis, which can also be used for other applications such as batteries, sensors, and bioimaging. 相似文献
5.
Directional Construction of Vertical Nitrogen‐Doped 1T‐2H MoSe2/Graphene Shell/Core Nanoflake Arrays for Efficient Hydrogen Evolution Reaction
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Shengjue Deng Yu Zhong Yinxiang Zeng Yadong Wang Zhujun Yao Fan Yang Shiwei Lin Xiuli Wang Xihong Lu Xinhui Xia Jiangping Tu 《Advanced materials (Deerfield Beach, Fla.)》2017,29(21)
The low utilization of active sites and sluggish reaction kinetics of MoSe2 severely impede its commercial application as electrocatalyst for hydrogen evolution reaction (HER). To address these two issues, the first example of introducing 1T MoSe2 and N dopant into vertical 2H MoSe2/graphene shell/core nanoflake arrays that remarkably boost their HER activity is herein described. By means of the improved conductivity, rich catalytic active sites and highly accessible surface area as a result of the introduction of 1T MoSe2 and N doping as well as the unique structural features, the N‐doped 1T‐2H MoSe2/graphene (N‐MoSe2/VG) shell/core nanoflake arrays show substantially enhanced HER activity. Remarkably, the N‐MoSe2/VG nanoflakes exhibit a relatively low onset potential of 45 mV and overpotential of 98 mV (vs RHE) at 10 mA cm?2 with excellent long‐term stability (no decay after 20 000 cycles), outperforming most of the recently reported Mo‐based electrocatalysts. The success of improving the electrochemical performance via the introduction of 1T phase and N dopant offers new opportunities in the development of high‐performance MoSe2‐based electrodes for other energy‐related applications. 相似文献
6.
Chuanyong Jian Qian Cai Wenting Hong Jing Li Wei Liu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(13)
Molybdenum diselenide (MoSe2) is widely considered as one of the most promising catalysts for the hydrogen evolution reaction (HER). However, the absence of active sites and poor conductivity of MoSe2 severely restrict its HER performance. By introducing a layer of MoO2 on Mo foil, MoSe2/MoO2 hybrid nanosheets with an abundant edge and high electrical conductivity can be synthesized on the surface of Mo foil. Metallic MoO2 can improve the charge transport efficiency of MoSe2/MoO2, thereby enhancing the overall HER performance. MoSe2/MoO2 exhibits fast hydrogen evolution kinetics with a small overpotential of 142 mV versus RHE at a current density of 10 mA cm?2 and Tafel slope of 48.9 mV dec?1. 相似文献
7.
Dezhi Xiao Qingdong Ruan De‐Liang Bao Yang Luo Chao Huang Siying Tang Jie Shen Cheng Cheng Paul K. Chu 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(25)
Plasma functionalization can increase the efficiency of MoSe2 in the hydrogen evolution reaction (HER) by providing multiple species but the interactions between the plasma and catalyst are not well understood. In this work, the effects of the ion energy and plasma density on the catalytic properties of MoSe2 nanosheets are studied. The through‐holes resulting from plasma etching and multi‐vacancies induced by plasma‐induced damage enhance the HER efficiency as exemplified by a small overpotential of 148 mV at 10 mA cm–2 and Tafel slope of 51.6 mV dec–1 after the plasma treatment using a power of 20 W. The interactions between the plasma and catalyst during etching and vacancies generation are evaluated by plasma simulation. Finite element and first‐principles density functional theory calculations are also conducted and the results are consistent with the experimental results, indicating that the improved HER catalytic activity stems from the enhanced electric field and more active sites on the catalyst, and reduced bandgap and adsorption energy arising from the etched through‐holes and vacancies, respectively. The results convey new fundamental knowledge about the plasma effects and means to enhance the efficiency of catalysts in water splitting as well insights into the design of high‐performance HER catalysts. 相似文献
8.
Zhi‐Wen Gao Mengjie Liu Weiran Zheng Xiandi Zhang Lawrence Yoon Suk Lee 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(44)
With excellent performance in the hydrogen evolution reaction (HER), molybdenum disulfide (MoS2) is considered a promising nonprecious candidate to substitute Pt‐based catalysts. Herein, pulsed laser irradiation in liquid is used to realize one‐step exfoliation of bulk 2H‐MoS2 to ultrastable few‐layer MoS2 nanosheets. Such prepared MoS2 nanosheets are rich in S vacancies and metallic 1T phase, which significantly contribute to the boosted catalytic HER activity. Protic solvents play a pivotal role in the production of S vacancies and 2H‐to‐1T phase transition under laser irradiation. MoS2 exfoliated in an optimal solvent of formic acid exhibits outstanding HER activity with an overpotential of 180 mV at 10 mA cm?2 and Tafel slope of 54 mV dec?1. 相似文献
9.
Huanyun Liao Xingzhong Guo Yang Hou Hao Liang Zheng Zhou Hui Yang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(10)
Designing elaborate nanostructures and engineering defects have been promising approaches to fabricate cost‐efficient electrocatalysts toward overall water splitting. In this work, a controllable Prussian‐blue‐analogue‐sacrificed strategy followed by an annealing process to harvest defect‐rich Ni‐Fe‐doped K0.23MnO2 cubic nanoflowers (Ni‐Fe‐K0.23MnO2 CNFs‐300) as highly active bifunctional catalysts for oxygen and hydrogen evolution reactions (OER and HER) is reported. Benefiting from many merits, including unique morphology, abundant defects, and doping effect, Ni‐Fe‐K0.23MnO2 CNFs‐300 shows the best electrocatalytic performances among currently reported Mn oxide‐based electrocatalysts. This catalyst affords low overpotentials of 270 (320) mV at 10 (100) mA cm?2 for OER with a small Tafel slope of 42.3 mV dec?1, while requiring overpotentials of 116 and 243 mV to attain 10 and 100 mA cm?2 for HER respectively. Moreover, Ni‐Fe‐K0.23MnO2 CNFs‐300 applied to overall water splitting exhibits a low cell voltage of 1.62 V at 10 mA cm?2 and excellent durability, even superior to the Pt/C||IrO2 cell at large current density. Density functional theory calculations further confirm that doping Ni and Fe into the crystal lattice of δ‐MnO2 can not only reinforce the conductivity but also reduces the adsorption free‐energy barriers on the active sites during OER and HER. 相似文献
10.
Sayyar Ali Shah Xiaoping Shen Minghua Xie Guoxing Zhu Zhenyuan Ji Hongbo Zhou Keqiang Xu Xiaoyang Yue Aihua Yuan Jun Zhu Yao Chen 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(9)
Developing cheap, abundant, and easily available electrocatalysts to drive the hydrogen evolution reaction (HER) at small overpotentials is an urgent demand of hydrogen production from water splitting. Molybdenum disulfide (MoS2) based composites have emerged as competitive electrocatalysts for HER in recent years. Herein, nickel@nitrogen‐doped carbon@MoS2 nanosheets (Ni@NC@MoS2) hybrid sub‐microspheres are presented as HER catalyst. MoS2 nanosheets with expanded interlayer spacings are vertically grown on nickel@nitrogen‐doped carbon (Ni@NC) substrate to form Ni@NC@MoS2 hierarchical sub‐microspheres by a simple hydrothermal process. The formed Ni@NC@MoS2 composites display excellent electrocatalytic activity for HER with an onset overpotential of 18 mV, a low overpotential of 82 mV at 10 mA cm?2, a small Tafel slope of 47.5 mV dec?1, and high durability in 0.5 H2SO4 solution. The outstanding HER performance of the Ni@NC@MoS2 catalyst can be ascribed to the synergistic effect of dense catalytic sites on MoS2 nanosheets with exposed edges and expanded interlayer spacings, and the rapid electron transfer from Ni@NC substrate to MoS2 nanosheets. The excellent Ni@NC@MoS2 electrocatalyst promises potential application in practical hydrogen production, and the strategy reported here can also be extended to grow MoS2 on other nitrogen‐doped carbon encapsulated metal species for various applications. 相似文献
11.
Synergistic Interlayer and Defect Engineering in VS2 Nanosheets toward Efficient Electrocatalytic Hydrogen Evolution Reaction
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Junjun Zhang Chenhui Zhang Zhenyu Wang Jian Zhu Zhiwei Wen Xingzhong Zhao Xixiang Zhang Jun Xu Zhouguang Lu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(9)
A simple one‐pot solvothermal method is reported to synthesize VS2 nanosheets featuring rich defects and an expanded (001) interlayer spacing as large as 1.00 nm, which is a ≈74% expansion as relative to that (0.575 nm) of the pristine counterpart. The interlayer‐expanded VS2 nanosheets show extraordinary kinetic metrics for electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 43 mV at a geometric current density of 10 mA cm?2, a small Tafel slope of 36 mV dec?1, and long‐term stability of 60 h without any current fading. The performance is much better than that of the pristine VS2 with a normal interlayer spacing, and even comparable to that of the commercial Pt/C electrocatalyst. The outstanding electrocatalytic activity is attributed to the expanded interlayer distance and the generated rich defects. Increased numbers of exposed active sites and modified electronic structures are achieved, resulting in an optimal free energy of hydrogen adsorption (?GH) from density functional theory calculations. This work opens up a new door for developing transition‐metal dichalcogenide nanosheets as high active HER electrocatalysts by interlayer and defect engineering. 相似文献
12.
Shengjue Deng Changzhi Ai Mi Luo Bo Liu Yan Zhang Yahao Li Shiwei Lin Guoxiang Pan Qinqin Xiong Qi Liu Xiuli Wang Xinhui Xia Jiangping Tu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(30)
Performance breakthrough of MoSe2‐based hydrogen evolution reaction (HER) electrocatalysts largely relies on sophisticated phase modulation and judicious innovation on conductive matrix/support. In this work the controllable synthesis of phosphate ion (PO43?) intercalation induced‐MoSe2 (P‐MoSe2) nanosheets on N‐doped mold spore carbon (N‐MSC) forming P‐MoSe2/N‐MSC composite electrocatalysts is realized. Impressively, a novel conductive N‐MSC matrix is constructed by a facile mold fermentation method. Furthermore, the phase of MoSe2 can be modulated by a simple phosphorization strategy to realize the conversion from 2H‐MoSe2 to 1T‐MoSe2 to produce biphase‐coexisted (1T‐2H)‐MoSe2 by PO43‐ intercalation (namely, P‐MoSe2), confirmed by synchrotron radiation technology and spherical aberration‐corrected TEM (SACTEM). Notably, higher conductivity, lower bandgap and adsorption energy of H+ are verified for the P‐MoSe2/N‐MSC with the help of density functional theory (DFT) calculation. Benefiting from these unique advantages, the P‐MoSe2/N‐MSC composites show superior HER performance with a low Tafel slope (≈51 mV dec‐1) and overpotential (≈126 mV at 10 mA cm‐1) and excellent electrochemical stability, better than 2H‐MoSe2/N‐MSC and MoSe2/carbon nanosphere (MoSe2/CNS) counterparts. This work demonstrates a new kind of carbon material via biological cultivation, and simultaneously unravels the phase transformation mechanism of MoSe2 by PO43‐ intercalation. 相似文献
13.
Bin Liu Hui‐Qing Peng Junye Cheng Kui Zhang Da Chen Dong Shen Shuilin Wu Tianpeng Jiao Xin Kong Qili Gao Shuyu Bu Chun‐Sing Lee Wenjun Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(48)
Development of high‐performance and low‐cost nonprecious metal electrocatalysts is critical for eco‐friendly hydrogen production through electrolysis. Herein, a novel nanoflower‐like electrocatalyst comprising few‐layer nitrogen‐doped graphene‐encapsulated nickel–copper alloy directly on a porous nitrogen‐doped graphic carbon framework (denoted as Nix Cuy @ NG‐NC) is successfully synthesized using a facile and scalable method through calcinating the carbon, copper, and nickel hydroxy carbonate composite under inert atmosphere. The introduction of Cu can effectively modulate the morphologies and hydrogen evolution reaction (HER) performance. Moreover, the calcination temperature is an important factor to tune the thickness of graphene layers of the Nix Cuy @ NG‐NC composites and the associated electrocatalytic performance. Due to the collective effects including unique porous flowered architecture and the synergetic effect between the bimetallic alloy core and graphene shell, the Ni3Cu1@ NG‐NC electrocatalyst obtained under optimized conditions exhibits highly efficient and ultrastable activity toward HER in harsh environments, i.e., a low overpotential of 122 mV to achieve a current density of 10 mA cm?2 with a low Tafel slope of 84.2 mV dec?1 in alkaline media, and a low overpotential of 95 mV to achieve a current density of 10 mA cm?2 with a low Tafel slope of 77.1 mV dec?1 in acidic electrolyte. 相似文献
14.
Qing‐Qing Pang Zhu‐Lin Niu Sha‐Sha Yi Shuo Zhang Zhong‐Yi Liu Xin‐Zheng Yue 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(34)
The design on synthesizing a sturdy, low‐cost, clean, and sustainable electrocatalyst, as well as achieving high performance with low overpotential and good durability toward water splitting, is fairly vital in environmental and energy‐related subject. Herein, for the first time the growth of sulfur (S) defect engineered self‐supporting array electrode composed of metallic Re and ReS2 nanosheets on carbon cloth (referred as Re/ReS2/CC) via a facile hydrothermal method and the following thermal treatment with H2/N2 flow is reported. It is expected that, for example, the as‐prepared Re/ReS2‐7H/CC for the electrocatalytic hydrogen evolution reaction (HER) under acidic medium affords a quite low overpotential of 42 mV to achieve a current density of 10 mA cm?2 and a very small Tafel slope of 36 mV decade?1, which are comparable to some of the promising HER catalysts. Furthermore, in the two‐electrode system, a small cell voltage of 1.30 V is recorded under alkaline condition. Characterizations and density functional theory results expound that the introduced S defects in Re/ReS2‐7H/CC can offer abundant active sites to advantageously capture electron, enhance the electron transport capacity, and weaken the adsorption free energy of H* at the active sites, being responsible for its superior electrocatalytic performance. 相似文献
15.
Molybdenum Carbide‐Decorated Metallic Cobalt@Nitrogen‐Doped Carbon Polyhedrons for Enhanced Electrocatalytic Hydrogen Evolution
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Electrocatalytic hydrogen evolution reaction (HER) based on water splitting holds great promise for clean energy technologies, in which the key issue is exploring cost‐effective materials to replace noble metal catalysts. Here, a sequential chemical etching and pyrolysis strategy are developed to prepare molybdenum carbide‐decorated metallic cobalt@nitrogen‐doped porous carbon polyhedrons (denoted as Mo/Co@N–C) hybrids for enhanced electrocatalytic hydrogen evolution. The obtained metallic Co nanoparticles are coated by N‐doped carbon thin layers while the formed molybdenum carbide nanoparticles are well‐dispersed in the whole Co@N–C frames. Benefiting from the additionally implanted molybdenum carbide active sites, the HER performance of Mo/Co@N–C hybrids is significantly promoted compared with the single Co@N–C that is derived from the pristine ZIF‐67 both in alkaline and acidic media. As a result, the as‐synthesized Mo/Co@N–C hybrids exhibit superior HER electrocatalytic activity, and only very low overpotentials of 157 and 187 mV are needed at 10 mA cm?2 in 1 m KOH and 0.5 m H2SO4, respectively, opening a door for rational design and fabrication of novel low‐cost electrocatalysts with hierarchical structures toward electrochemical energy storage and conversion. 相似文献
16.
Jinlong Liu Zhenyu Wang Jun Li Lujie Cao Zhouguang Lu Dongdong Zhu 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(4)
Oxygen and phosphorus dual‐doped MoS2 nanosheets (O,P‐MoS2) with porous structure and continuous conductive network are fabricated using a one‐pot NaH2PO2‐assisted hydrothermal approach. By simply changing the precursor solution, the chemical composition and resulting structure can be effectively controlled to obtain desired properties toward the hydrogen evolution reaction (HER). Thanks to the beneficial structure and strong synergistic effects between the incorporated oxygen and phosphorus, the optimal O,P‐MoS2 exhibit superior electrocatalytic performances compared with those of oxygen single‐doped MoS2 nanosheets (O‐MoS2). Specifically, a low HER onset overpotential of 150 mV with a small Tafel slope of 53 mV dec?1, excellent conductivity, and long‐term durability are achieved by the structural engineering of MoS2 via O and P co‐doping, making it an efficient HER electrocatalyst for water electrocatalysis. This work provides an alternative strategy to manipulate transition metal dichalcogenides as advanced materials for electrocatalytic and related energy applications. 相似文献
17.
Yu Zhou Joshua V. Pondick Jose Luis Silva John M. Woods David J. Hynek Grace Matthews Xin Shen Qingliang Feng Wen Liu Zhixing Lu Zhixiu Liang Barbara Brena Zhao Cai Min Wu Liying Jiao Shu Hu Hailiang Wang Carlos Moyses Araujo Judy J. Cha 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(19)
Using the MoS2‐WTe2 heterostructure as a model system combined with electrochemical microreactors and density function theory calculations, it is shown that heterostructured contacts enhance the hydrogen evolution reaction (HER) activity of monolayer MoS2. Two possible mechanisms are suggested to explain this enhancement: efficient charge injection through large‐area heterojunctions between MoS2 and WTe2 and effective screening of mirror charges due to the semimetallic nature of WTe2. The dielectric screening effect is proven minor, probed by measuring the HER activity of monolayer MoS2 on various support substrates with dielectric constants ranging from 4 to 300. Thus, the enhanced HER is attributed to the increased charge injection into MoS2 through large‐area heterojunctions. Based on this understanding, a MoS2/WTe2 hybrid catalyst is fabricated with an HER overpotential of ?140 mV at 10 mA cm?2, a Tafel slope of 40 mV dec?1, and long stability. These results demonstrate the importance of interfacial design in transition metal dichalcogenide HER catalysts. The microreactor platform presents an unambiguous approach to probe interfacial effects in various electrocatalytic reactions. 相似文献
18.
Wencui Zhang Xiaobin Liao Xuelei Pan Mengyu Yan Yanxi Li Xiaocong Tian Yan Zhao Lin Xu Liqiang Mai 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(31)
In the hydrogen evolution reaction (HER), energy‐level matching is a prerequisite for excellent electrocatalytic activity. Conventional strategies such as chemical doping and the incorporation of defects underscore the complicated process of controlling the doping species and the defect concentration, which obstructs the understanding of the function of band structure in HER catalysis. Accordingly, 2H‐MoS2 and 1T‐MoS2 are used to create electrocatalytic nanodevices to address the function of band structure in HER catalysis. Interestingly, it is found that the 2H‐MoS2 with modulated Fermi level under the application of a vertical electric field exhibits excellent electrocatalytic activity (as evidenced by an overpotential of 74 mV at 10 mA cm?2 and a Tafel slope of 99 mV per decade), which is superior to 1T‐MoS2. This unexpected excellent HER performance is ascribed to the fact that electrons are injected into the conduction band under the condition of back‐gate voltage, which leads to the increased Fermi level of 2H‐MoS2 and a shorter Debye screen length. Hence, the required energy to drive electrons from the electrocatalyst surface to reactant will decrease, which activates the 2H‐MoS2 thermodynamically. 相似文献
19.
Pengzuo Chen Tianpei Zhou Mengxing Zhang Yun Tong Chengan Zhong Nan Zhang Lidong Zhang Changzheng Wu Yi Xie 《Advanced materials (Deerfield Beach, Fla.)》2017,29(30)
Developing non‐noble‐metal electrocatalysts with high activity and low cost for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is of paramount importance for improving the generation of H2 fuel by electrocatalytic water‐splitting. This study puts forward a new N‐anion‐decorated Ni3S2 material synthesized by a simple one‐step calcination route, acting as a superior bifunctional electrocatalyst for the OER/HER for the first time. The introduction of N anions significantly modifies the morphology and electronic structure of Ni3S2, bringing high surface active sites exposure, enhanced electrical conductivity, optimal HER Gibbs free‐energy (ΔGH*), and water adsorption energy change (ΔGH2O*). Remarkably, the obtained N‐Ni3S2/NF 3D electrode exhibits extremely low overpotentials of 330 and 110 mV to reach a current density of 100 and 10 mA cm?2 for the OER and HER in 1.0 m KOH, respectively. Moreover, an overall water‐splitting device comprising this electrode delivers a current density of 10 mA cm?2 at a very low cell voltage of 1.48 V. Our finding introduces a new way to design advanced bifunctional catalysts for water splitting. 相似文献
20.
Ik Seon Kwon Tekalign Terfa Debela In Hye Kwak Yun Chang Park Jaemin Seo Ju Yong Shim Seung Jo Yoo Jin‐Gyu Kim Jeunghee Park Hong Seok Kang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(13)
2D MoS2 nanostructures have recently attracted considerable attention because of their outstanding electrocatalytic properties. The synthesis of unique Co–Ru–MoS2 hybrid nanosheets with excellent catalytic activity toward overall water splitting in alkaline solution is reported. 1T′ phase MoS2 nanosheets are doped homogeneously with Co atoms and decorated with Ru nanoparticles. The catalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is characterized by low overpotentials of 52 and 308 mV at 10 mA cm?2 and Tafel slopes of 55 and 50 mV decade?1 in 1.0 m KOH, respectively. Analysis of X‐ray photoelectron and absorption spectra of the catalysts show that the MoS2 well retained its metallic 1T′ phase, which guarantees good electrical conductivity during the reaction. The Gibbs free energy calculation for the reaction pathway in alkaline electrolyte confirms that the Ru nanoparticles on the Co‐doped MoS2 greatly enhance the HER activity. Water adsorption and dissociation take place favorably on the Ru, and the doped Co further catalyzes HER by making the reaction intermediates more favorable. The high OER performance is attributed to the catalytically active RuO2 nanoparticles that are produced via oxidation of Ru nanoparticles. 相似文献