Nanoscale
·
2016
·Vol. 8
·期 21
·11052-11059
·
IF 7.76
Aiping Wu,Chungui Tian,Haijing Yan,Yanqing Jiao,Qing Yan,Guoyu Yang,Honggang Fu
A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core–shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized condition, HF-MoSP exhibits excellent electrocatalytic activity for HER with a low onset overpotential of 29 mV and η of 108 mV at 10 mA cm−2 in 0.5 M H2SO4 and retains its good activity for 30 h. In addition, the catalyst shows excellent activity in 1 M KOH with an onset overpotential of 42 mV and η of 119 mV at 10 mA cm−2. The catalysts also exhibit obvious activity in neutral, weak acid and weak alkaline conditions. The good performance is relative to the synergy of the MoP shell and MoS2 core and the high WF of HF-MoSP close to Pt, and the large SBET of HF-MoSP benefited from the hierarchical structure. This study represents the construction of the core–shell heterojunction and provides a new way to provide the low-cost and high-performance catalyst for HER.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Juan Du,Qiao Han,Cheng Liu,Hongda Wu,Lufan zheng,Zhanxu Yang
The surface modification strategy has broken through the restriction of hydrogen evolution activity caused by low conductivity inert surfaces of MoS 2 during hydrogen evolution reaction . In this work, a new strategy for regulating the interface structure between MoS 2 and MoP using sulfur vacancy is proposed, which is derived from the synthesis of molybdenum disulfide nanotubes with rich S-vacancy (Sv-MoS 2 ) by reduction. Subsequently, Sv-MoS 2 was phosphated by introducing a P source, and the obtained (MoP/Sv-MoS 2 -8) composite. The introduction of P atoms provides more active sites for hydrogen adsorption and desorption by replacing S atoms to form (Mo-P) covalent bonds , further increase the number of S vacancies to activate the inert interface. The synthesized MoP/Sv-MoS 2 -8 has excellent catalytic activity and good cyclic stability, showing a lower Tafel slope of 60 mV·dec −1 at a current density of 10 mA·cm −2 , and no potential attenuation after the cyclic stability test for 24 h. The excellent HER performance is mainly due to the synergistic effect of P atom doping and S vacancy, which greatly reduces the energy barrier of the Volmer step and the adsorption/desorption of the H* intermediate step.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2017
·Vol. 4
·期 11
·1791-1797
·
IF 4.036
Jiangli Meng,Jiaqi Fu,Xiaoxuan Yang,Meijie Wei,Song Liang,Hong-Ying Zang,Huaqiao Tan,Yonghui Wang,Yangguang Li
The development of stable, highly active and cheap electrocatalysts towards the oxygen evolution reaction (OER) has been an ongoing challenge due to practical problems such as slow kinetics and high overpotential. Herein, we utilized a one-pot hydrothermal method to prepare cobalt/nickel molybdate hierarchical microflowers on conductive carbon cloth (MMoO4-CC, M = Co, Ni) as three-dimensional self-supported electrodes for the oxygen evolution reaction. CoMoO4-CC showed better catalytic activity than NiMoO4-CC. Benefiting from the synergistic effect of a large active area, fast charge and mass transport as well as a three-dimensional conducting path, the CoMoO4-CC nanosheet electrode showed a large current density and a relatively low starting potential, delivering 10 mA cm−2 current densities at an overpotential of 290 mV and a Tafel slope of 94 mV dec−1. Furthermore, the CoMoO4-CC nanomaterial shows better electrocatalytic stability than IrO2-CCa, which could be a promising electrocatalyst for large-scale water oxidation.
研究领域:
电催化
·
材料科学
·
能源化学
·
电化学
·
纳米材料
✓ 已验证
DOI
高影响因子
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
·
2016
·Vol. 254
·期 4
·1600245
·
IF 1.522
Song Hao,Bingchu Yang,Yongli Gao
Monolayer MoS 2 is an emerging two-dimensional semiconductor with wide-ranging potential applications in novel optoelectronic devices and catalysis. Here, we report the growth of drop-like monolayer MoS 2 /MoO 2 granular films on SiO 2 /Si substrate by chemical vapor deposition method. The as-synthesized films were systematically characterized by various means of optical microscopy, X-ray/ultraviolet photoemission spectroscopy, scanning electron microscopy, atomic/kelvin force microscopy, X-ray diffraction, Raman and photoluminescence techniques. The combined results of atomic force microscopy and scanning electron microscopy clearly present novel drop-like granulars and domain boundaries, ascribed to lower growth temperature. X-ray photoemission spectroscopy results complemented by Raman and X-ray diffraction results confirm the formation of MoS 2 /MoO 2 granular films. The ultraviolet photoemission spectroscopy, along with kelvin force microscopy, reveals a different nature of surface potential of drop-like MoS 2 granular films compared with crystalline MoS 2 , owing to electron transfer from MoS 2 to MoO 2 and drop-like structure. Our study broadens the scope of two-dimensional transition metal dichalcogenides research and reveals the distinct physical properties of drop-like monolayer MoS 2 granular films.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Liwei Zhang,Tianqi Wang,Ying Yang,Meijie Wei,Feng Li,Hui Yu,Xiangting Dong
MoS 2 is a promising gas sensing material due to its low resistance and low operating temperature. But the sensitivity of MoS 2 is limited by fast electron-hole complexation. In this work, phosphomolybdic acid (PMo 12 ) was used as precursor. After sulfurizing by one-step hydrothermal method , the generated MoS 2 and unspent PMo 12 can in-situ form MoS 2 /PMo 12 composite nanospheres . The gas sensing performances of the composite were comprehensively investigated. By adjusting hydrothermal reaction temperature, optimized sensitivity (MoS 2 /PMo 12 -240) to NO 2 gas can be gained. At a low operating temperature of 80 °C, the optimized response value to 100 ppm NO 2 gas is 2.466, which is higher than most reported MoS 2 -based NO 2 sensors. Moreover, MoS 2 /PMo 12 -240 composite also exhibits good selectivity, repeatability, long-term stability and humidity resistance. The mechanism of sensing performance enhancement was also analyzed and discussed. As a semiconductor-like material, PMo 12 can form heterojunction together with MoS 2 . The valence band of PMo 12 can capture the holes in MoS 2 and effectively suppresses electron-hole complexation. Thus the sensing performance can be improved. This work provides a new strategy for designing and constructing high performance sulfide composite gas sensors by introducing POMs .
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Materials and Technologies
·
2024
·
IF 8.6
Mingyuan Zhu,Lijun Yu,Simiao Sha,Riyue Ge,Chi Cheng,Liming Dai,Sean Li,Bin Liu,Zhixue Qu,Wenxian Li
Energy consumption associated with the catalysts contributes partly to the high ohmic resistance arising from the low conductivity of the catalyst and poor charge transfer between nanoparticles, which has been difficult to study due to the complicated nanostructured framework of the catalysts. We constructed a novel heterostructure electrocatalyst (MoS 2 /MoP@NC) composed of nanosized MoS 2 /MoP heterostructures anchoring on hierarchical N-doped carbon for smoothing electron transfer in boosting hydrogen evolution reaction (HER). With the merits of large surface area, rapid charge transfer, and optimized electronic structure induced by charge transfer across the sufficient interface, the optimal MoS 2 /MoP@NC (MoSP) catalyst shows a competitive overpotential of 140 (0.5 M H 2 SO 4 ), 76 (1.0 M KOH), and 103 mV (0.5 M NaCl &1.0 M KOH) at 10 mA cm −2 , respectively. Raman experiment and Density functional theory (DFT) calculations reveal the formation of Mo-S-Mo bonds between MoS 2 and MoP, which favor enhancing the Femi level to facilitate the electron transfer, therefore regulating the electronic structure for the optimization of adsorption energy of hydrogen intermediate. Based on the experimental results, we constructed an energy consumption model of catalysts, where energy consumption comes from three aspects. The heterostructure design decreases the energy consumption of the catalysts greatly compared to the single-phase Mo-based catalyst of MoS 2 (78.0%) and MoP (45.2%) in alkaline electrolytes.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL SCIENCES
·
2024
·Vol. 40
·期 3
·461-469
·
IF 1.8
Li Li,Zhang Jiahua,Deng Zhichen,Su Zhengquan,Bai Yan,He Jincan
This paper proposed a rapid, selective and sensitive molybdenum yellow derivatization coupled with Resonance Rayleigh scattering (MYD-RRS) method for detection of phosphate. Under the acidic condition, phosphate can be selectively transformed to Keggin type of phosphomolybdic acid (PMA, i.e., PMo 12 O 40 3− ) through molybdenum yellow derivatization reaction prior to RRS detection. The PMA can further react with cationic methyl violet (MV) to form larger PMA-MV ion association complexes, generating significant RRS signal. The concentration of phosphate was linearly related to the RRS signal in the range of 8–200 ng/mL, with the determining coefficient ( R 2 ) of 0.9973 and the detection limit of 4 ng/mL. The analytical procedure can be completed within 10 min and the RRS signal intensity can remain stable more than 4 h. The method showed good stability toward temperature and time, and good anti-interference capability. The method was applied to the determination of phosphate in real food samples with the recovery of 85–117% and RSD of 1–5.2%. With the advantages of rapidness, high sensitivity and good selectivity, the MYD-RRS method exhibits great potential to the determination of phosphate in food. It also provides an instructive strategy for detection of analytes with weak RRS signal. Graphical abstract
研究领域:
分析化学
·
食品科学
✓ 已验证
DOI
PubMed
高影响因子
SOLAR ENERGY
·
2020
·
IF 4.608
Yu Zhang,Ping Su,Linqing Liu,Pengfei Qiu,Li Su,Guangsheng Fu,Wei Yu
Achieving large Fermi energy splitting under illumination is critical for improving the performance of photovoltaic devices. In this work, we conducted the energy band structure modulation of MoS 2 thin films via MoO x doping scheme to realize its photovoltaic operation on n-type c-Si by magnetron sputtering. It is found that, by capping a MoO x overlayer, the MoS 2 electrons density decreased and the Fermi level shifted ~0.4 eV towards valence band, consequently the MoS 2 conductive type changing. With this doped MoS 2 layer, the built-in electric field of fabricated MoS 2 /n-Si heterojunction devices greatly improved and exceeded 400 mV owing to the larger interface energy-level differences. Meanwhile, the defects recombination losses reduced benefiting from the holes-selective behavior of O-deficiencies in MoO x , so that the photo-generated carriers extraction process were promoted. As a result, the doped MoS 2 /n-Si devices showed excellent rectification behavior with rectifying ratio to 10 5 and ideality of 1.12. The TRPL spectrums corroborated the enhanced carrier transport mechanism at MoS 2 /n-Si interface by MoO x modulation doping effect. Correspondingly, the significant improvement of doped MoS 2 /n-Si solar cells performance (V oc of 289 mV, FF of 60.72% and J sc of 31.25 mA/cm 2 ) was achieved, exhibiting an optimized conversion efficiency of 5.47%. The UPS analysis revealed that the doping mechanism of MoO x /MoS 2 stacks lies in energy band overlap and electrons contact transfer between these two materials. This observation of MoO x modulation doping effect on large-area sputtering MoS 2 could help in building a better interface carrier transport in photovoltaic and optoelectronic applications of 2D materials.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 46
·17235-17240
·
IF 4.39
Liujun Deng,Yu Zou,Jiang Jiang
Plasmonic hybrid catalysts have attracted great interest for the reduction of nitrobenzene waste to valuable aminobenzene, because they can use renewable solar energy to accelerate the catalytic reaction. However, the economical synthesis of non-precious plasmonic hybrid catalysts remains a big challenge. Herein we report the synthesis of plasmonic MoO2-embedded MoNi4 nanosheets (MoNi4–MoO2) by thermal annealing of NiMoO4 at 600 °C under a hydrogen atmosphere. The MoNi4–MoO2 hybrid catalysts retain strong plasmon absorption from MoO2 and demonstrate good catalytic activity from MoNi4 for 4-nitrophenol reduction in the dark. Under visible light irradiation, the excitation of MoO2 plasmon promotes the catalytic reaction further due to hot electron-induced increase of catalytic activity of MoNi4. In addition, the hybrid catalysts are relatively stable even under illumination reaction conditions.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Shihang Meng,Xiaoxiao Xue,Yujing Weng,Siyi Jiang,Guang Li,Qi Sun,Yulong Zhang
Molybdenum carbide is a noble-metal-like material, which shows great potential in many applications. The conventional Temperature-Programmed-Reduction (TPRe) method uses carbonaceous gases to carburize with molybdenum precursors, which has made a significant progress but still hard to scale up. In this work, molybdenum carbides were prepared by carburization of ammonium molybdenum molybdate on cellulose, g-C 3 N 4 , MWCNTs and sodium lignosulfonate without using any gaseous carbon source. Moreover, the formation of molybdenum carbide was subjected to in-depth investigation by using an in situ Simultaneous Thermal Analyzer – Quadrupole Mass Spectrometry coupling System. The technique revealed that the solid carbon carriers do have a great effect on the formation of molybdenum carbides. Furthermore, various characterization methods such as XRD, SEM, CO-TPD, FTIR and organic element analysis (OEA) were also applied to investigate the property of prepared molybdenum carbides. The results suggested that the prepared molybdenum carbides with CEL, MWCNTs and SLF as carbon supports could retain the skeleton and porous structure of a solid carbon carrier, and the prepared molybdenum carbides with g-C 3 N 4 as a carbon support could generate a new three-dimensional (3D) structure support, and the composition of carriers would also have an impact on the adsorption and physicochemical properties of molybdenum carbides.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2022
·Vol. 74
·期 7
·2742-2749
·
IF 2.597
Zhang Rui-Hua,Hao Zhen-Hua,Shi Lin-Yuan,Chen Hao-Tian,Shu Yong-Chun,He Ji-Lin
In this present study, carbothermic reduction process of MoO 3 to produce MoO 2 has been carried to investigate the influences of reaction temperature and distance between activated carbon and MoO 3 on phase composition of reduction products by controlling carbon diffusion. Results show that the reduction degree increases with the increase of temperature and the decrease of distance between activated carbon and MoO 3 . MoO 3 can be completely reduced to MoO 2 at 680°C with the carbon distance of 1 mm. It is found that the transformation from MoO 3 to MoO 2 is a process of crystal cracking and growth by observing the phase transition and morphological evolution during the reduction. The massive MoO 3 is first decomposed into a platelet-shaped MoO x (2.75 < x < 3), then the platelet-shaped MoO x changes into a needle-like shape or irregular platelet-like Mo 4 O 11 , and finally Mo 4 O 11 changes into irregular granular or irregular platelet-like shaped crystals, which form MoO 2 powders.
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
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Chaoyun Tang,Qi Hu,Fengjiao Li,Chuanxin He,Xiaoyan Chai,Caizhen Zhu,Jianhong Liu,Qianling Zhang,Bin Zhu,Liangdong Fan
Electrochemical water splitting by electricity from the renewable power sources is one of the most promising pathways for green and sustainable hydrogen production . The key is to synthesize earth-abundant and noble-metal-free electrocatalysts with outstanding hydrogen evolution reaction (HER) activity and durability in wide-pH electrolytes by simple and cost-effective methods. Herein, we reported a one-step synthesis of uniform, ultrafine molybdenum carbide (Mo 2 C) and molybdenum nitride (Mo 2 N) hybrid [together as Mo 2 (CN)] inserted carbon nanosheets as efficient electrocatalyst for HER. The as-synthesized catalyst showed an excellent HER activity in acid medium, and even superior performance was obtained in the alkaline medium. The optimal Mo 2 (CN) annealed at 750 °C showed an overpotential of −80 mV at 10 mA cm −2 and a Tafel slope of 40 mV dec −1 ; the former strikingly outperforms commercial 20% Pt/C materials (−112 mV). Moreover, Mo 2 (CN) gave an onset voltage of −33 mV and overpotential of −202 mV at 100 mA cm −2 with merely a mass loading of 0.2 mg cm −2 , which are, to date, among the best records for Mo-based catalysts in both media. The nanosheet structure providing large active area and quick charge transfer, and the synergistic effects between Mo 2 C and Mo 2 N toward HER are ascribed to the outstanding electrocatalytic activity according to the capacitive current and turnover frequency analysis. The remarkable catalytic activity and operational durability in wide pH ranges guarantee their potential for highly efficient hydrogen production.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）