共查询到20条相似文献,搜索用时 719 毫秒
1.
Liuqing He Wenbiao Zhang Qijie Mo Wenjie Huang Lichun Yang Qingsheng Gao 《Angewandte Chemie (International ed. in English)》2020,59(9):3544-3548
Heterostructured Mo2C‐MoOx on carbon cloth (Mo2C‐MoOx/CC), as a model of easily oxidized electrocatalysts under ambient conditions, is investigated to uncover surface reconfiguration during the hydrogen evolution reaction (HER). Raman spectroscopy combined with electrochemical tests demonstrates that the MoVI oxides on the surface are in situ reduced to MoIV, accomplishing promoted HER in acidic condition. As indicated by density functional theoretical calculations, the in situ reduced surface with terminal Mo=O moieties can effectively bring the negative ΔGH* on bare Mo2C close to a thermodynamic neutral value, addressing difficult H* desorption toward fast HER kinetics. The optimized Mo2C‐MoOx/CC only requires a low overpotential (η10) of 60 mV at ?10 mA cm?2 in 1.0 m HClO4, outperforming Mo2C/CC and most non‐precious electrocatalysts. In situ surface reconfiguration are shown on W2C‐WOx, highlighting the significance to boost various metal‐carbides and to identify active sites. 相似文献
2.
Jiayuan Yu Wanqiang Yu Bin Chang Xiao Li Jin Jia Dufu Wang Zhinian Xu Xiaoli Zhang Hong Liu Weijia Zhou 《中国化学快报》2022,33(6):3231-3235
Tailor-made advanced electrocatalysts with high active and stable for hydrogen evolution reaction (HER)play a key role in the development of hydrogen economy.Herein,a N,P-co-doped molybdenum carbide confined in porous carbon matrix (N,P-Mo2C/NPC) with a hierarchical structure is prepared by a resources recovery process.The N,P-Mo2C/NPC compound exhibits outstanding HER activity with a low overpotential of 84 mV to achieve 10 mA/cm2,and excellent stability in alka... 相似文献
3.
Liuqing He Wenbiao Zhang Qijie Mo Wenjie Huang Prof. Dr. Lichun Yang Prof. Dr. Qingsheng Gao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3572-3576
Heterostructured Mo2C-MoOx on carbon cloth (Mo2C-MoOx/CC), as a model of easily oxidized electrocatalysts under ambient conditions, is investigated to uncover surface reconfiguration during the hydrogen evolution reaction (HER). Raman spectroscopy combined with electrochemical tests demonstrates that the MoVI oxides on the surface are in situ reduced to MoIV, accomplishing promoted HER in acidic condition. As indicated by density functional theoretical calculations, the in situ reduced surface with terminal Mo=O moieties can effectively bring the negative ΔGH* on bare Mo2C close to a thermodynamic neutral value, addressing difficult H* desorption toward fast HER kinetics. The optimized Mo2C-MoOx/CC only requires a low overpotential (η10) of 60 mV at −10 mA cm−2 in 1.0 m HClO4, outperforming Mo2C/CC and most non-precious electrocatalysts. In situ surface reconfiguration are shown on W2C-WOx, highlighting the significance to boost various metal-carbides and to identify active sites. 相似文献
4.
《化学:亚洲杂志》2017,12(4):446-452
Here we report a redox‐anchoring strategy for synthesizing a non‐noble metal carbide (MoCx) nanocomposite electrocatalyst for water electrolysis in acidic media, using glucose and ammonium heptamolybdate as carbon and Mo precursors, respectively, without the need of gaseous carbon sources such as CH4. Specifically, the aldehyde groups of glucose are capable of reducing Mo6+ to Mo4+ (MoO2), and thus molybdenum species can be well anchored by a redox reaction onto a carbon matrix to prevent the aggregation of MoCx nanoparticles during the following carbonization process. The morphology and chemical composition of the electrocatalysts were well characterized by BSE‐SEM, TEM, XRD and XPS. The obtained MoCx−2 sample showed a reasonably high hydrogen evolution reaction (HER) activity and excellent stability in an acidic electrolyte, and its overpotential required for a current density output of 20 mA cm−2 is as low as 193 mV. Such a prominent performance is ascribed to the excellent dispersity and nano‐size, and the large reactive surface area of MoCx particles. This work may open a new way to the design and fabrication of other non‐noble metal carbide nanocatalysts for various electrochemical applications. 相似文献
5.
Changchun Ji Guang Yang P. Robert Ilango Junnan Song Deshuang Yu Sujun Han Dongxing Zhang Linlin Li Shengjie Peng 《化学:亚洲杂志》2020,15(13):1957-1962
With the environmental pollution and non‐renewable fossil fuels, it is imperative to develop eco‐friendly, renewable, and highly efficient electrocatalysts for sustainable energy. Herein, a simple electrospinning process used to synthesis Mo2C‐embedded multichannel hollow carbon nanofibers (Mo2C‐MCNFs) and followed by the pyrolysis process. As prepared lotus root‐like nanoarchitecture could offer rich porosity and facilitate the electrolyte infiltration, the Mo2C‐MCNFs delivered favourable catalytic activity for HER and OER. The resultant catalysts exhibit low overpotentials of 114 mV and 320 mV at a current density of 10 mA cm?2 for HER and OER, respectively. Furthermore, using the Mo2C‐MCNFs catalysts as a bifunctional electrode toward overall water splitting, which only needs a small cell voltage of 1.68 V to afford a current density of 10 mA cm?2 in the home‐made alkaline electrolyzer. This interesting work presents a simple and effective strategy to further fabricating tunable nanostructures for energy‐related applications. 相似文献
6.
Ultrafine Molybdenum Carbide Nanoparticles Composited with Carbon as a Highly Active Hydrogen‐Evolution Electrocatalyst 下载免费PDF全文
Ruguang Ma Yao Zhou Yongfang Chen Pengxi Li Prof. Qian Liu Prof. Jiacheng Wang 《Angewandte Chemie (International ed. in English)》2015,54(49):14723-14727
The replacement of platinum with non‐precious‐metal electrocatalysts with high efficiency and superior stability for the hydrogen‐evolution reaction (HER) remains a great challenge. Herein, we report the one‐step synthesis of uniform, ultrafine molybdenum carbide (Mo2C) nanoparticles (NPs) within a carbon matrix from inexpensive starting materials (dicyanamide and ammonium molybdate). The optimized catalyst consisting of Mo2C NPs with sizes lower than 3 nm encapsulated by ultrathin graphene shells (ca. 1–3 layers) showed superior HER activity in acidic media, with a very low onset potential of ?6 mV, a small Tafel slope of 41 mV dec?1, and a large exchange current density of 0.179 mA cm?2, as well as good stability during operation for 12 h. These excellent properties are similar to those of state‐of‐the‐art 20 % Pt/C and make the catalyst one of the most active acid‐stable electrocatalysts ever reported for HER. 相似文献
7.
Developing highly efficient, cost-saving, and durable multifunctional electrocatalysts for oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) continues to be a significant challenge in the energy field. In this work, we decide to prepare an unusual multifunctional electrocatalyst, such as icosahedral palladium nanocrystals (PdNCs) encapsulating on N–MoO2–Mo2C half-hollow nanotube (HHNT) heterointerface, using an in-situ chemical reaction and following sonic probe irradiation method. All the experiments demonstrate that special defect-enriched heterointerfaces N–MoO2–Mo2C supported Pd nanocomposite can greatly improve the ORR activity (Eonset = 1.01 V and E1/2 = 0.90 V) with good stability, outstanding HER (η10 = 65 mV) and OER (η10 = 180 mV) performances than those of commercial precious electrocatalysts (Platinum on carbon [Pt/C] and ruthenium oxide [RuO2]). The overall water splitting electrolyzer fabricates by Pd/N–MoO2–Mo2C as both anode and cathode electrodes to achieve a current density of 10 Ma/cm2 at a cell voltage of 1.56 V, which surpasses the most recent reported electrocatalysts. 相似文献
8.
Dr. Ze-Xing Cai Dr. Jongbeom Na Prof. Jianjian Lin Prof. Abdulmohsen Ali Alshehri Prof. Khalid Ahmed Alzahrani Prof. Yousef Gamaan Alghamdi Hyunsoo Lim Dr. Jie Zheng Dr. Wei Xia Prof. Zhong-Li Wang Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6195-6204
Developing efficient electrocatalysts for the hydrogen evolution reaction (HER) is crucial for establishing a sustainable and environmentally friendly energy system, but it is still a challenging issue. Herein, hierarchical tubular-structured CoS2-MoS2/C as efficient electrocatalysts are fabricated through a unique metal–organic framework (MOF) mediated self-sacrificial templating. Core–shell structured MoO3@ZIF-67 nanorods are used both as a precursor and a sacrificial template to form the one-dimensional tubular heterostructure where vertically aligned two-dimensional CoS2-MoS2 nanosheets are formed on the MOF-derived carbon tube. Trace amounts of noble metals (Pd, Rh, and Ru) are successfully introduced to enhance the electrocatalytic property of the CoS2-MoS2/C nanocomposites. The as-synthesized hierarchical tubular heterostructures exhibit excellent HER catalytic performance owing to the merits of the hierarchical hollow architecture with abundantly exposed edges and the uniformly dispersed active sites. Impressively, the optimal Pd-CoS2-MoS2/C-600 catalyst delivers a current density of 10 mA cm−2 at a low overpotential of 144 mV and a small Tafel slope of 59.9 mV/dec in 0.5 m H2SO4. Overall, this MOF-mediated strategy can be extended to the rational design and synthesis of other hollow heterogeneous catalysts for scalable hydrogen generation. 相似文献
9.
Porous Molybdenum Phosphide Nano‐Octahedrons Derived from Confined Phosphorization in UIO‐66 for Efficient Hydrogen Evolution 下载免费PDF全文
Jian Yang Fengjun Zhang Xin Wang Dongsheng He Geng Wu Qinghua Yang Xun Hong Yuen Wu Yadong Li 《Angewandte Chemie (International ed. in English)》2016,55(41):12854-12858
Herein, a series of porous nano‐structured carbocatalysts have been fused and decorated by Mo‐based composites, such as Mo2C, MoN, and MoP, to form a hybrid structures. Using the open porosity derived from the pyrolysis of metal–organic frameworks (MOFs), the highly dispersive MoO2 small nanoparticles can be deposited in porous carbon by chemical vapor deposition (CVD). Undergoing different treatments of carbonization, nitridation, and phosphorization, the Mo2C‐, MoN‐, and MoP‐decorated carbocatalysts can be selectively prepared with un‐changed morphology. Among these Mo‐based composites, the MoP@Porous carbon (MoP@PC) composites exhibited remarkable catalytic activity for the hydrogen evolution reaction (HER) in 0.5 m H2SO4 aqueous solution versus MoO2@PC, Mo2C@PC, and MoN@PC. This study gives a promising family of multifunctional lab‐on‐a‐particle architectures which shed light on energy conversion and fuel‐cell catalysis. 相似文献
10.
A novel free-standing pie-like paper electrode composed of Mo2C nanobeads on graphene-coated carbon nanofibers (G-CNF) membrane was rationally designed as advanced electrocatalyst for hydrogen evolution reaction (HER). A thin layer of graphene is coated on the surface of CNF membrane, forming a “crust” on fibrous web architecture. The unique design of the all-carbon membrane, which is a 3D interconnected conductive framework of nanofibers, reduces the resistance of electron and ion transport during the electrocatalyzing process. With G-CNF performing as support, well-shaped Mo2C nanobeads were immobilized on the fibers through hydrothermal and calcination procedures, offering rich catalytic sites on the exposed rough surface. Owing to all these merits, the composite membrane of Mo2C-G-CNF exhibits high HER catalytic activity with onset potential of 115 mV in acidic solution and 108 mV in basic solution. Furthermore, the good durability in both acidic and basic environment guarantees its practical application as free-standing electrode material. 相似文献
11.
Cheng Wang Prof. Limin Qi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17372-17377
The development of transition-metal-oxides (TMOs)-based bifunctional catalysts toward efficient overall water splitting through delicate control of composition and structure is a challenging task. Herein, the rational design and controllable fabrication of unique heterostructured inter-doped ruthenium–cobalt oxide [(Ru–Co)Ox] hollow nanosheet arrays on carbon cloth is reported. Benefiting from the desirable compositional and structural advantages of more exposed active sites, optimized electronic structure, and interfacial synergy effect, the (Ru–Co)Ox nanoarrays exhibited outstanding performance as a bifunctional catalyst. Particularly, the catalyst showed a remarkable hydrogen evolution reaction (HER) activity with an overpotential of 44.1 mV at 10 mA cm−2 and a small Tafel slope of 23.5 mV dec−1, as well as an excellent oxygen evolution reaction (OER) activity with an overpotential of 171.2 mV at 10 mA cm−2. As a result, a very low cell voltage of 1.488 V was needed at 10 mA cm−2 for alkaline overall water splitting. 相似文献
12.
Polyoxometalate and Resin‐Derived P‐Doped Mo2C@N‐Doped Carbon as a Highly Efficient Hydrogen‐Evolution Reaction Catalyst at All pH Values 下载免费PDF全文
Dr. Gang Yan Dr. Xiaojia Feng Dr. Shifa Ullah Khan Dr. Liguang Xiao Wenguang Xi Dr. Huaqiao Tan Dr. Yuanyuan Ma Dr. Lunan Zhang Prof. Yangguang Li 《化学:亚洲杂志》2018,13(2):158-163
A new type of P‐doped Mo2C coated by N‐doped carbon (P‐Mo2C@NC) has been successfully prepared by calcining a mixture of H3[PMo12O40] polyoxometalates (POMs) and urea‐formaldehyde resin under an N2 atmosphere. Urea‐formaldehyde resin not only serves as the carbon source to ensure carbonization but also facilitates the uniform distribution of POM precursors, which efficiently avoid the aggregation of Mo2C particles at high temperatures. TEM analysis revealed that the average diameter of the Mo2C particles was about 10 nm, which is coated by a few‐layer N‐doped carbon sheet. The as‐prepared P‐Mo2C@NC displayed excellent hydrogen‐evolution reaction (HER) performance and long‐term stability in all pH environments. To reach a current density of 10 mA cm?2, only 109, 159, and 83 mV were needed for P‐Mo2C@NC in 0.5 m H2SO4 (pH 0), 0.1 m phosphate buffer (pH 7), and 1 m KOH (pH 14), respectively. This could provide a high‐yield and low‐cost method to prepare uniform nanosized molybdenum carbides with highly efficient and stable HER performance. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(41):12740-12744
Uniform Ni3C nanodots dispersed in ultrathin N‐doped carbon nanosheets were successfully prepared by carburization of the two dimensional (2D) nickel cyanide coordination polymer precursors. The Ni3C based nanosheets have lateral length of about 200 nm and thickness of 10 nm. When doped with Fe, the Ni3C based nanosheets exhibited outstanding electrocatalytic properties for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For example, 2 at % Fe (atomic percent) doped Ni3C nanosheets depict a low overpotential (292 mV) and a small Tafel slope (41.3 mV dec−1) for HER in KOH solution. An outstanding OER catalytic property is also achieved with a low overpotential of 275 mV and a small Tafel slope of 62 mV dec−1 in KOH solution. Such nanodot‐incorporated 2D hybrid structures can serve as an efficient bifunctional electrocatalyst for overall water splitting. 相似文献
14.
Dr. Yu‐Jia Tang Dr. Min‐Rui Gao Dr. Chun‐Hui Liu Prof. Shun‐Li Li Prof. Hai‐Long Jiang Prof. Ya‐Qian Lan Prof. Min Han Prof. Shu‐Hong Yu 《Angewandte Chemie (International ed. in English)》2015,54(44):12928-12932
We have synthesized a porous Mo‐based composite obtained from a polyoxometalate‐based metal–organic framework and graphene oxide (POMOFs/GO) using a simple one‐pot method. The MoO2@PC‐RGO hybrid material derived from the POMOFs/GO composite is prepared at a relatively low carbonization temperature, which presents a superior activity for the hydrogen‐evolution reaction (HER) in acidic media owing to the synergistic effects among highly dispersive MoO2 particles, phosphorus‐doped porous carbon, and RGO substrates. MoO2@PC‐RGO exhibits a very positive onset potential close to that of 20 % Pt/C, low Tafel slope of 41 mV dec?1, high exchange current density of 4.8×10?4 A cm?2, and remarkable long‐term cycle stability. It is one of the best high‐performance catalysts among the reported nonprecious metal catalysts for HER to date. 相似文献
15.
Kedong Xia Junpo Guo Cuijuan Xuan Ting Huang Zhiping Deng Lingxuan Chen Deli Wang 《中国化学快报》2019,30(1):192-196
Nitrogen doped carbon nanosheets supported molybdenum carbides nanoparticles (MoxC/NCS) have been synthesized by tuning the mass ratio of melamine and ammonia molybdate. The Mo2C/NCS-10 exhibits superior electrocatalytic performance and stability for HER, which was attributed to N-doped carbon nanosheets, small particle size, mesoporous structure, and large electrochemical active surface area. 相似文献
16.
《化学:亚洲杂志》2017,12(1):36-40
N‐doped mesoporous carbon‐capped MoO2 nanobelts (designated as MoO2@NC) were synthesized and applied to lithium‐ion storage. Owing to the stable core–shell structural framework and conductive mesoporous carbon matrix, the as‐prepared MoO2@NC shows a high specific capacity of around 700 mA h g−1 at a current of 0.5 A g−1, excellent cycling stability up to 100 cycles, and superior rate performance. The N‐doped mesoporous carbon can greatly improve the conductivity and provide uninhibited conducting pathways for fast charge transfer and transport. Moreover, the core–shell structure improved the structural integrity, leading to a high stability during the cycling process. All of these merits make the MoO2@NC to be a suitable and promising material for lithium ion battery. 相似文献
17.
Jifan Li Lei Liu Dr. Yongjian Ai Dr. Zenan Hu Prof. Liping Xie Hongjie Bao Jiajing Wu Haimeng Tian Rongxiu Guo Shucheng Ren Wenjuan Xu Prof. Hongbin Sun Prof. Gang Zhang Prof. Qionglin Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7191-7200
Facile and large-scale preparation of materials with uniform distributions of ultrafine particles for catalysis is a challenging task, and it is even more difficult to obtain catalysts that excel in both the hydrogen evolution reaction (HER) and hydrogenation, which are the corresponding merging and splitting procedures of hydrogen, respectively. Herein, the fabrication of ultrafine bimetallic PtNi nanoparticles embedded in carbon nanosheets (CNS) by means of in situ self-polymerization and annealing is reported. This bifunctional catalyst shows excellent performance in the hydrogen evolution reaction (HER) and the hydrogenation of p-nitrophenol. Remarkably PtNi bimetallic catalyst with low metal loading (PtNi2@CNS-600, 0.074 wt % Pt) exhibited outstanding HER activity with an overpotential as low as 68 mV at a current density of 10 mA cm−2 with a platinum loading of only 0.612 μgPt cm−2 and Tafel slope of 35.27 mV dec−1 in a 0.5 m aqueous solution of H2SO4, which is comparable to that of the 20 % Pt/C catalyst (31 mV dec−1). Moreover, it also shows superior long-term electrochemical durability for at least 30 h with negligible degradation compared with 20 % Pt/C. In addition, the material with increased loading (mPtNi2@CNS-600, 2.88 % Pt) showed robust catalytic activity for hydrogenation of p-nitrophenol at ambient pressure and temperature. The catalytic activity towards hydrogen splitting is a circumstantial evidence that agrees with the Volmer–Tafel reaction path in the HER. 相似文献
18.
Coupling Mo2C with Nitrogen‐Rich Nanocarbon Leads to Efficient Hydrogen‐Evolution Electrocatalytic Sites 下载免费PDF全文
Yipu Liu Prof. Guangtao Yu Prof. Guo‐Dong Li Yuanhui Sun Prof. Tewodros Asefa Prof. Wei Chen Prof. Xiaoxin Zou 《Angewandte Chemie (International ed. in English)》2015,54(37):10752-10757
In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one‐step facile synthesis of a novel precious‐metal‐free hydrogen‐evolution nanoelectrocatalyst, dubbed Mo2C@NC that is composed of ultrasmall molybdenum carbide (Mo2C) nanoparticles embedded within nitrogen‐rich carbon (NC) nanolayers. The Mo2C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen‐evolution reaction (HER) over a wide pH range (pH 0–14). Theoretical calculations show that the Mo2C and N dopants in the material synergistically co‐activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(38):11717-11722
Highly active, stable, and cheap Pt‐free catalysts for the hydrogen evolution reaction (HER) are under increasing demand for future energy conversion systems. However, developing HER electrocatalysts with Pt‐like activity that can function at all pH values still remains as a great challenge. Herein, based on our theoretical predictions, we design and synthesize a novel N,P dual‐doped carbon‐encapsulated ruthenium diphosphide (RuP2@NPC) nanoparticle electrocatalyst for HER. Electrochemical tests reveal that, compared with the Pt/C catalyst, RuP2@NPC not only has Pt‐like HER activity with small overpotentials at 10 mA cm−2 (38 mV in 0.5 m H2SO4, 57 mV in 1.0 m PBS and 52 mV in 1.0 m KOH), but demonstrates superior stability at all pH values, as well as 100 % Faradaic yields. Therefore, this work adds to the growing family of transition‐metal phosphides/heteroatom‐doped carbon heterostructures with advanced performance in HER. 相似文献
20.
Dr. Ying Wang Dr. Wenming Sun Xiaofei Ling Xiangkai Shi Dr. Lanlan Li Prof. Yida Deng Dr. Cuihua An Dr. Xiaopeng Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4097-4103
The development of high-efficiency, low-cost, and earth-abundant electrocatalysts for overall water splitting remains a challenge. In this work, Ni-modified MoS2 hybrid catalysts are grown on carbon cloth (Ni-Mo-S@CC) through a one-step hydrothermal treatment. The optimized Ni-Mo-S@CC catalyst shows excellent hydrogen evolution reaction (HER) activity with a low overpotential of 168 mV at a current density of 10 mA cm−2 in 1.0 m KOH, which is lower than those of Ni-Mo-S@CC (1:1), Ni-Mo-S@CC (3:1), and pure MoS2. Significantly, the Ni-Mo-S@CC hybrid catalyst also displays outstanding oxygen evolution reaction (OER) activity with a low overpotential of 320 mV at a current density of 10 mA cm−2, and remarkable long-term stability for 30 h at a constant current density of 10 mA cm−2. Experimental results and theoretical analysis based on density functional theory demonstrate that the excellent electrocatalytic performance can be attributed mainly to the remarkable conductivity, abundant active sites, and synergistic effect of the Ni-doped MoS2. This work sheds light on a unique strategy for the design of high-performance and stable electrocatalysts for water-splitting electrolyzers. 相似文献