SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhenzhong Liu,Suyue Luo,Xinran Yin,Shuo Zhang,Minghui Guo
The present work effectively achieved the production of a self-supporting electrode with high efficiency. The process involves incorporating nickel and molybdenum carbide (Mo 2 C) phases within the channels of wood through high-temperature calcination at the nanoscale. The obtained carbonized wood (CW) possesses low tortuosity and three-dimensional vertical channels, providing an excellent substrate for the preparation of Ni-Mo 2 C/N-CW electrodes. Mo 2 C is well known for its considerable potential as a non-precious metal electrocatalyst with enhanced catalytic activity. The successful doping of nickel and nitrogen into molybdenum carbide not only promotes the formation of β-Mo 2 C, but also improves the electron transfer rate and mass diffusion pathway. Consequently, the Ni-Mo 2 C/N-CW electrode exhibits excellent performance in the hydrogen and oxygen evolution reactions (HER and OER, respectively). Only voltages of 89 and 253 mV are required to achieve a current density of 10 mA cm −2 , respectively. When the Ni-Mo 2 C/N-CW catalyst is used as both cathode and anode during hydrolysis, current densities of 10 and 100 mA cm −2 can be achieved with excellent durability and stability at voltages of 1.56 and 1.72 V, respectively. The distinctive porous structure of the wood substrate is of crucial importance for promoting the adsorption and dissociation of water molecules, enhancing the catalytic performance. In addition, the present material exhibits advantageous characteristics, including a high specific surface area and a significant number of adsorption sites, making it a very promising candidate for applications involving the adsorption of dyes, such as rhodamine B (RhB).
研究领域:
材料科学
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电化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2022
·Vol. 28
·期 1
·192
·
IF 4.927
Yunjie Huang,Yaqi Bao,Tieqi Huang,Chengzhi Hu,Haiou Qiu,Hongtao Liu
Molybdenum carbide is considered to be one of the most competitive catalysts for hydrogen evolution reaction (HER) regarding its high catalytic activity and superior corrosion resistance. But the low electrical conductivity and poor interfacial contact with the current collector greatly inhibit its practical application capability. Herein, carbon nanotube (CNT) supported molybdenum carbide was assembled via electrostatic adsorption combined with complex bonding. The N-doped molybdenum carbide nanocrystals were uniformly anchored on the surfaces of amino CNTs, which depressed the agglomeration of nanoparticles while strengthening the migration of electrons. The optimized catalyst (250-800-2h) showed exceptional electrocatalytic performance towards HER under both acidic and alkaline conditions. Especially in 0.5 M H2SO4solution, the 250-800-2h catalyst exhibited a low overpotential of 136 mV at a current density of 10 mA/cm2(η10) with the Tafel slope of 49.9 mV dec−1, and the overpotential only increased 8 mV after 20,000 cycles of stability test. The active corrosive experiment revealed that more exposure to high-activity γ-Mo2N promoted the specific mass activity of Mo, thus, maintaining the catalytic durability of the catalyst.Keywords:molybdenum carbide;carbon nanotube;electrocatalyst;hydrogen evolution reaction
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2023
·Vol. 35
·期 6
·065704
·
IF 3.5
Xiaomei Yu,Wei Shi,Jiajiao Wei,Tiantian Liu,Yuanyuan Li,Mengyuan He,Zhengyu Wei,Dehai Ping,Panfei Sun,Jin You Zheng,Songjie Li
Developing non-noble-metal electrocatalysts for hydrogen evolution reactions with high activity and stability is the key issue in green hydrogen generation based on electrolytic water splitting. It has been recognized that the stacking of large CoP particles limits the intrinsic activity of as-synthesized CoP catalyst for hydrogen evolution reaction. In the present study, N-MoxC/CoP-0.5 with excellent electrocatalytic activity for hydrogen evolution reaction was prepared using N-MoxC as decoration. A reasonable overpotential of 106 mV (at 10 mA cm−2) and a Tafel slope of 59 mV dec−1 in 1.0 M KOH solution was achieved with N-MoxC/CoP-0.5 electrocatalyst, which exhibits superior activity even after working for 37 h. Uniformly distributed ultrafine nanoclusters of the N-MoxC/CoP-0.5 hybrids could provide sufficient interfaces for enhanced charge transfer. The effective capacity of the hydrogen evolution reaction could be preserved in the complex, and the enlarged electrocatalytic surface area could be expected to offer more active sites for the reaction.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Minghao Hu,Hengyi Chen,Baocang Liu,Xuan Xu,Bo Cao,Peng Jing,Jingjing Zhang,Rui Gao,Jun Zhang
In this study, we report a novel self-supported electrode consisting of ceria/molybdenum carbides composite microrods with adjustable crystalline phases and abundant heterostructures on carbon cloth (CeO 2 /Mo x C/CC). The optimized CeO 2 /α-MoC/β-Mo 2 C MRs/CC electrode exhibits very low overpotentials of 22 and 29 mV at 10 mA cm −2 for hydrogen evolution reaction (HER) in alkaline freshwater and seawater, outperforming most of the reported molybdenum carbide-based electrocatalysts. Meanwhile, it could maintain long-term stability for over 100 h at a large current density of 1000 mA·cm −2 . Theoretical study and experimental results reveal that the synergistic effects of α-MoC, β-Mo 2 C, and oxygen vacancy-rich CeO 2 can effectively promote the dissociation of water molecules, tailor the d‐band electronic structure of Mo x C with a thermoneutral hydrogen adsorption free energy , increase the numbers of active sites, and facilitate the vectorial electron transfer, thus achieving an enhanced HER performance. The CeO 2 /α-MoC/β-Mo 2 C MRs/CC electrode displays a potential large-scale application in hydrogen generation.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Deguang Zhang,Wenbo Liu,Runwei Wang,Zongtao Zhang,Shilun Qiu
Constructing favorable nanostructure to make full use of excited charges is considered as a feasible approach to boost the photocatalytic performance of semiconductor catalysts. High dispersed Pt-like cocatalysts would provide generous reaction sites as well as accelerating the charge transfer. Herein, an in-situ method is developed to cover molybdenum carbide/carbon layer on the surface of flower-like TiO 2 and eventually form a hierarchical TiO 2 @Mo 2 C/C photocatalyst. The resulting heterostructure exhibits photocatalytic activity of 10.21 mmol h −1 g −1 which is 21 times higher than normal TiO 2 and achieved high stability for more than 16 h. By further analyses such as photoluminescence (PL) and surface photovoltage (SPV), the enhancement of photocatalytic activity could be explained by fast charge separation and utilization. Theoretical calculation shows the superiority of flower-like TiO 2 for coexposed active facets. The unique method of in-situ construction could be helpful to obtain functional integrating catalysts for proton-coupled electron transfers (PCETs) photocatalytic reactions.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2019
·Vol. 31
·期 10
·105707
·
IF 3.399
Zijian Chen,Ting Guo,Zhuangzhi Wu,Dezhi Wang
As highly efficient non-precious metal-based catalysts for the hydrogen evolution reaction (HER), molybdenum carbides have attracted much attention over the phase and structure modification for the improvement of HER performances. In this work, a novel strategy is proposed to modulate phases of molybdenum carbides by boron doping, so that the HER performances can be well controlled. After B-doping, the HER activity of the as-prepared B30 catalyst is significantly enhanced with a much smaller Tafel slope of 78 mV dec−1 than that of the blank one (134 mV dec−1), which originates from the increased amount of active sites, enhanced turnover frequency of each active site and reduced electron transfer resistance. Moreover, this work could broaden our view of phase regulation and provide more possible perspectives for the application in other fields.
研究领域:
材料科学
·
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Xinghang Duan,Zebing Wang,Tiantian Cao,Qiaolin Li,Gang Chen,Hongtao Guan,Chengjun Dong
Although molybdenum carbide (Mo x C) has emerged as an effective absorber of electromagnetic (EM) waves, its practical application is hindered by impedance mismatch and single loss mechanism. Herein, we developed a one-step method for creating NaCl template precursors assembled with ZIF-67 to produce porous multiple components of Mo x C composites. The Mo x C-Co/C composites exhibit a minimum reflection loss ( RL min ) of −59.69 dB with a bandwidth of 3.12 GHz at a thickness of 1.50 mm. The RL min reaches −71.39 dB with a bandwidth of 4.08 GHz at a thickness of 2.09 mm. The flower-like Mo x C-Co/C composites are capable of improving impedance matching and offering multiple loss mechanisms such as interfacial polarization, dipolar polarization, conductive loss and magnetic loss, resulting in enhanced EM wave absorption. Thus, our work featured a simple strategy to provide a unique insight into fabricating high-performance EM wave absorbers on molybdenum carbon basis.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 30
·18030-18038
·
IF 10.733
Chaoyun Tang,Hui Zhang,Kuofeng Xu,Qianling Zhang,Jianhong Liu,Chuanxin He,Liangdong Fan,Tewodros Asefa
The development of noble metal-free catalysts, which can replace noble metal ones, such as Pt, for various electrocatalytic processes in renewable energy devices is currently of huge interest. The β-phase of molybdenum carbide (i.e., β-Mo2C) has been reported to be one of the most active noble metal-free electrocatalysts for the hydrogen evolution reaction (HER) in electrolyzers, whereas the other phases, MoC and MoC1−x, have been widely regarded as weak electrocatalysts for HER. Herein, we report the synthesis of nanoporous substoichiometric α-MoC1−x and η-MoC nanosheets, named np-MoC NSs, that show comparable electrocatalytic activity toward HER as β-Mo2C does. The materials are synthesized using two-dimensional (2D) conjugated carbonitride and ammonium molybdate as precursors. Their structures contain N dopant atoms and nanopores. The pores create highly accessible catalytic sites and good mass and charge transport, and thereby excellent reaction kinetics for HER, in the materials. Theoretical calculations show that the N dopant atoms modulate the electronic properties of the catalytically active sites in the materials, leading to lower free energy of adsorption and desorption for the hydrogen species involved in the reaction and better catalytic activity for HER. This work demonstrates that, by simple structural design and electronic modulation, various phases of molybdenum carbides and related materials that have been traditionally considered inactive catalysts for HER can be made robust electrocatalysts for the reaction.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Peng Zuo,Yefeng Liu,Xiaolei Liu,Weizhou Jiao,Ruixin Wang
Based on the ever-growing interest of heteroatoms (e.g., P, N, S, transition metals) doping into molybdenum carbide and graphene for electrochemical reactions , herein, a ternary phosphomolybdic acid-polyethyleneimine/graphene oxide nanocomposite as a suitable precursor was developed to not only uniformly hybridize molybdenum and carbon source to perform the controllable in situ growth of well-defined molybdenum carbide nanostructure on graphene by annealing, but also synchronously dope N and P atoms into molybdenum carbide crystal lattice and graphene. The as-prepared hybrid showed remarkable electrocatalytic activity and high stability for hydrogen evolution reaction in basic media, due to the following favorable features, i.e. a large accessible active sites afforded by the ultrafine molybdenum carbide, the heteroatoms doped, the regulated electronic structure, the balanced thermodynamics between hydrogen adsorption and desorption , the accelerated charge/mass transfer ability by the ultrathin and defective carbon layer , and the protection of molybdenum carbide by carbon layer. As a result, it only needed a small overpotential of 47 mV to drive 10 mA cm −2 and a low onset potential of 10 mV, as well as a small Tafel slope of 56.8 mV·dec −1 , thus suggesting its promising potential for hydrogen evolution electrocatalyst .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Energy
·
2022
·
IF 9.257
Luyao Zheng,Cong Liu,Sinong Wang,Boxu Gao,Xueliang Fan,Shuyu Xu,Yingshuai Jia,Yahong Zhang,Qingsheng Gao,Xiaoming Cao,Yi Tang
Transition metal carbides (TMCs) are regarded as cost-efficient and stable electrocatalysts for hydrogen evolution reaction (HER). Nitrogen doping into nanosized TMCs in a control manner (e.g. doping amount and site) is one of the most effective routes to intrinsically enhance the activity and durability owing to the ameliorated Mo–H strength and amplified active sites. Herein, an approach based on reticular chemistry is developed to synthesize nanosized N-doped Mo 2 C embedded in porous carbon (N–Mo 2 C/PC), via pyrolyzing a hybrid precursor consisting of highly-dispersed molybdates within melamine-benzenetricarboxylic acid supermolecule networks. With optimal N-doping, the N–Mo 2 C/PC electrocatalyst exhibits an excellent HER stability and activity with overpotential of 109 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 , as well as 100 mV at 10 mA cm −2 in 1.0 M KOH. Density functional theory calculations confirm that the appropriate N doping on the surface of Mo 2 C nanoparticles would accelerate the HER process via weakening the Mo–H bond strength and lowering the H–H coupling barrier. Furthermore, Mo 2 C nanoparticles loaded on carbon cloth with high HER activity can also be successfully achieved by this strategy. This work paves a universal way to design active sites-enriched TMCs with high performance in energy conversion and storages.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2025
·
IF 5.5
Zhaonan Chong,Run Cai,Change Yao,Zihan Wei,Pengfei Diao,JiaYi Liao,Shuwen Yang,Xin Chen,Huijuan Zhang,Zhong Ma
Molybdenum carbide (Mo2C) has been considered as one of the most promising electrocatalysts toward hydrogen evolution reaction (HER) due to its platinum-like electronic configuration, low cost, and good corrosion resistance. However, there are still great challenges in real activity and durability for large-scale applications. Herein, we report the ultrasmall Mo2C nanoparticles with a particle size less than 2 nm anchored on porous carbon exhibits excellent HER performance with the overpotentials (η10) of 156 mV and 130 mV in acidic and alkaline electrolytes, respectively. Furthermore, it also delivers a very stable life-span performance at a current density of around 20 mA cm–2 over 50 h with negligible decay. The nanopores in porous carbon are employed as nanoreactors to allow the reaction between its inside surface carbon atoms and Mo precursor to form the anchored Mo2C nanoparticles while avoiding the overgrowth of Mo2C particles at high temperatures in the annealing process. The high HER activity may be ascribed to the efficient exposure of active sites for ultrasmall particle size and the improved electron conductivity and ion transportation in the micro-3D configuration of the anchored structure in carbon pores.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
Qingtao Wang,Fangfang Mi,Jian Li,Yanxia Wu,Xiaozhong Zhou,Guofu Ma,Shufang Ren
Renewable hydrogen energy has been regarded as ideal green energy. There is an urgent need for efficient and stable non-noble metal electrocatalysts for hydrogen evolution reaction (HER). Molybdenum carbide (Mo x C) has excellent intrinsic activity and stability, which is expected as one of the ideal candidates to replace Pt. Herein, we report a facile Tungsten (W) doping method to regulate the crystal structure of Mo x C to generate a Mo 2 C-MoC heterostructure. It reduces the charge transfer resistance and regulates adsorption and desorption of hydrogen, thereby promoting the HER in alkaline solution. Besides, the carbon matrix not only increases the conductivity, but also protects the active site of W-Mo x C/C from agglomeration and deactivation due to high temperature. Under alkaline media, the W-Mo x C/C has improved HER catalytic activity. In 1 M KOH, an overpotential of 178 mV is required to reach a current density of 10 mA cm −2 , and the Tafel slope is 54.3 mV dec −1 . Moreover, it has a small charge transfer resistance and good stability. This work develops a multi-effect doping method that generates heterostructure and increases the active sites, which providing a new strategy for the performance regulation of other electrocatalysts.
研究领域:
材料科学
·
电催化
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）