JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
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IF 9.965
Yunqing Liu,Xuefeng Wang,Yuanna Zhu,Haiqing Wang,Jinghua Yu,Hong Liu,Shenguang Ge
Engineering of robust nonprecious electrocatalysts toward anodic oxygen evolution reaction (OER) is of great significance for lowering the cost and energy consumption for renewable fuel production. Herein, we report NiFeMoO x nanosheets as high-performance OER electrocatalyst through promoting the thermodynamic-limiting oxidation cycle process in NiFe oxyhydroxide via high-valence Mo doping. The NiFeMoO x nanosheets are prepared by an elaborate in-situ solvothermal etching-depositing process with NiFe alloy framework as substrate and metal precursors. The resultant nanosheets exhibit outstanding alkaline OER activity, requires only 235/282/327 mV overpotentials to achieve current density of 10/100/300 mA cm −2 , respectively, with a good long-term stability at 20 mA cm −2 for 72 h. Besides, the Tafel slope low to 28.1 mV dec −1 indicates a favorable OER kinetics. The superior catalytic activity of NiFeMoO x nanosheets should be attributed to the lower oxidation states of Ni and Fe induced by high-valence dopant , leading to easier surface reconstruction at low charge oxidation cycling during OER, thereby effectively reducing the overpotential. The synergy between the electronic effect among multimetallic sites and the unique morphology is expected to inspire the development of robust OER electrocatalyst for industrial application.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Linwei Jiang,Yichen Pan,Jiancheng Zhang,Xin Chen,Xinwen Ye,Zhendong Li,Caicai Li,Qingfeng Sun
Replacing the sluggish oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is an appealing tactic in the energy-saving water splitting system. Herein, by a facile composite electrodeposition method, an electrocatalyst with Mo particles anchored on the Ni-P matrix (Mo/Ni-P) was fabricated and utilized for urea-assisted water electrolysis of hydrogen production. As expected, the urea-involved electrolytic cell with the as-obtained Mo/Ni-P served as both the anode and cathode merely needs a voltage of 1.55 V to sustain a current density of 50 mA cm −2 (0.16 V less than that of the conventional water splitting at 50 mA cm −2 ) and can maintain the stability for 12 h. Additionally, the solar-driven urea-assisted water electrolysis system was constructed under lab conditions and solar-hydrogen-electricity energy conversion processes were also simulated. Moreover, it was demonstrated that tungsten (W) particles can also serve as an accelerant for promotion both the hydrogen evolution reaction (HER) and UOR activity of pristine Ni-P. This work will present a facile method for rational integration of metal particles with Ni-P layer for highly efficient electrocatalysts applied in economic production of H 2 .
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Materials Today Chemistry
·
2022
·
IF 7.613
S. Yang,Y. Cheng,T. E,Y. Wang,L. Liu,Y. Li,D. Wang,J. Qian
The inert substrate surface of MoS 2 leads to unsatisfactory adsorption performance. Herein, an inert substrate surface activation strategy is proposed, and the resulted MoS 2 /montmorillonite (MMT) prepared via the hydrothermal method is immersed with NaF (F–Mt). The intercalation of Na + contributes to inducing the transformation of MoS 2 from 2H phase to 1 T phase, thereby providing a large number of S vacancies and exposing available Mo 4+ . Meanwhile, the surface of MMT is activated due to the fact that partially [Si 4 O 10 ] 4- are etched by F - , which facilitates forming Si–O–Mo bonds to promote the charge transfer. The improved charge transfer rate can make S 2- in MoS 2 accumulate more negative charges, greatly enhancing the adsorption capacity to Pb 2+ . Moreover, the natural negative potential on the surface of MMT solves the problem of easy stacking for nanosheets , improving the availability of active sites on the edge, which are also benefit from the etching effect on MoS 2 nanosheets with NaF. The maximum adsorption capacity achieves 97.09 mg/g. Additionally, density functional theory (DFT) calculations confirm the resulted S vacancies in MoS 2 are in favor of removing Pb 2+ , which is also contributed by the electrostatic and chemical adsorption with MMT. Therefore, it suggests that F–Mt is an excellent adsorbent for Pb 2+ .
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
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IF 24.319
Shuisen He,Tingting Huang,Yu Fan
Novel alumina-supported Ni-Mo hydrodesulfurization (HDS) catalysts were prepared via assembly of Mo and Al precursors induced by tetradecylamine (TDA). Compared with conventional impregnation, this assembly method improves Mo dispersion, weakens metal-support interactions, enhances Ni modification at MoS 2 edge sites, and produces more NiMoS phases on Al 2 O 3 . The optimal NiMoS microstructure was obtained by modulating the TDA/Mo ratio in the assembly. A microstructure-activity correlation indicated that the S vacancies at the NiMoS corner sites favored σ-adsorption and direct desulfurization of 4,6-dimethylbenzothiophene (4,6-DMDBT), and those at the NiMoS edge sites promoted C-S breaking in hydrogenated derivatives of 4,6-DMDBT. Among these catalysts, NiTMo-2.0/Al 2 O 3 , which had the most corner and edge S vacancies, exhibited the highest reaction rate constant of 5.89 × 10 −7 mol·g −1 ·s −1 and the highest desulfurization ratio of 99.5% in HDS of 4,6-DMDBT.
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Frontiers in Chemistry
·
2022
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IF 5.545
Hu Yanru,Zhang Gengrui,Liu Lele,Chi ZiXin,Wang Shuai,Lin Jingdong,Xiong Haifeng,Wan Shaolong
The thermocatalytic conversion of hexose into valuable chemicals such as methyl lactate under mild conditions is very appealing. Here, we report that Mo, Mg co-modified Sn-β catalyst can effectively catalyze the transformation of glucose and fructose into alkyl lactate at moderate temperatures. A maximum yield of around 35% of methyl lactate was achieved from the conversion of glucose in methanol at 100°C over Sn-β catalyst modified with 3 wt% Mo and 0.5 wt% Mg. However, up to 82.8% yield of ethyl lactate was obtained in the case of fructose in ethanol upon the same catalytic condition, suggesting a significant solvent effect. The Mo species plays a key role to enable the retro-aldol condensation of fructose, in which the competing side reactions are significantly suppressed with the assistance of neighboring Mg species probably through a synergetic effect of Lewis acid-base.
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 22
·7445-7453
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IF 6.119
Yijuan Wang,Ziyi Guo,Jianzhi Wang,Ningbo Yu,Yanan Xue,Faquan Yu
Crystal structure and morphology can be regulated by inducing the positioning growth of metal sulfide, which is an efficient strategy to improve the oxygen evolution activity of the anode. Herein, solid NiMoO4 nanoplate arrays were used as cages to immobilize the metal source, and Mo doped NiSx is obtained by in situ solvothermal sulfuration reaction with polysulfide as the sulfur source. The electronic structure, conductivity, crystallographic phase and microscopic morphology of oxygen evolution catalysts could be controlled simultaneously by polysulfide induced solid metal oxide sulfidation, thereby greatly improving their electrocatalytic oxygen evolution activity. Benefiting from these, the prepared Mo doped nickel-sulfur electrodes show great performance toward the oxygen evolution reaction with overpotentials of 184 mV and 240 mV at current densities of 50 and 100 mA cm−2 in alkaline electrolyte. This study provides a new pathway by polysulfide induced sulfidation based on solid metal oxide for developing metal sulfide electrode materials with high oxygen evolution reaction performance for overall water splitting.
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JOURNAL OF MOLECULAR LIQUIDS
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2021
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IF 6.165
Bingqiao Yang,Pengliang Huang,Qing An
A small molecular triazole derivative called AMT (3-amino-5-mercapto-1,2,4-triazole) was explored as a novel and efficient chalcopyrite depressant in the preferential flotation of chalcopyrite from molybdenite. The flotation performances were comprehensively investigated via micro-flotation tests of singe and mixed minerals with and without Cu collector. The adsorption mechanisms were determined in terms of contact angle, adsorption capacity, and zeta potential, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and DFT calculations. Single mineral flotation results illustrated that the AMT selectively depressed chalcopyrite over a wide range of pH values. Particularly, AMT was able to depress chalcopyrite even in the presence of sodium isobutyl xanthate (SIBX). The contact angle, adsorption capacity, zeta potential, and FTIR results suggested that AMT was preferentially adsorbed on chalcopyrite surface, but it barely interacted with molybdenite. XPS tests and DFT calculations demonstrated that AMT was chemically adsorbed on chalcopyrite surface through the hybridization of S (1) and N (1) 2p orbitals of AMT with the Cu (1) 3d orbital. The bonding between S (1) atom and Cu (1) was much stronger than that between N (1) and Cu (1). Thus, AMT exhibited good potential as a novel depressant due to its excellent selectivity and practicability.
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Energies
·
2021
·Vol. 15
·期 1
·53
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IF 3.004
Kai Miao,Tan Li,Jing Su,Cong Wang,Kaige Wang
Catalytic hydropyrolysis via the introduction of external hydrogen into catalytic pyrolysis process using hydrodeoxygenation catalysts is one of the major approaches of bio-oil upgrading. In this study, hydrodeoxygenation of acetone over Mo/HZSM-5 and HZSM-5 were investigated with focus on the influence of hydrogen pressure and catalyst deactivation. It is found that doped MoO3could prolong the catalyst activity due to the suppression of coke formation. The influence of hydrogen pressure on catalytic HDO of acetone was further studied. Hydrogen pressure of 30 bar effectively prolonged catalyst activity while decreased the coke deposition over catalyst. The coke formation over the HZSM-5 and Mo/HZSM-5 under 30 bar hydrogen pressure decreased 66% and 83%, respectively, compared to that under atmospheric hydrogen pressure. Compared to the test with the HZSM-5, 35% higher yield of aliphatics and 60% lower coke were obtained from the Mo/HZSM-5 under 30 bar hydrogen pressure. Characterization of the spent Mo/HZSM-5 catalyst revealed the deactivation was mainly due to the carbon deposition blocking the micropores and Bronsted acid sites. Mo/HZSM-5 was proved to be potentially enhanced production of hydrocarbons.Keywords:hydrodeoxygenation;biomass;hydropyrolysis;MoO3;bifunctional catalysts
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JOM
·
2021
·Vol. 73
·期 11
·3451-3459
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IF 2.474
Chen Ben,Li Zhi-Bo,Zhang Guo-Hua,Chou Kuo-Chih
To improve the performance of Mo-based cermets, Mo-(Ni)-Al 2 O 3 cermets were prepared with raw materials of nano-sized Al 2 O 3 powder. The effects of Al 2 O 3 and Ni additions on the densification behavior, microstructure, bending strength, and hardness of the Mo-(Ni)-Al 2 O 3 cermets were experimentally analyzed. The results showed the content of Al 2 O 3 had a great influence on the degree of densification of Mo-Al 2 O 3 cermets at the sintering temperature of 1600°C. In addition, the Al 2 O 3 particles were distributed evenly in the matrix of Mo-based cermets, which refined the grains of Mo and increased the hardness of cermets. Because of the weak interfacial bonding strength between Al 2 O 3 ceramic phase and Mo metal phase, the bending strength decreased continuously with increasing Al 2 O 3 content. However, Ni addition improved the wetting and adhesion of Al 2 O 3 and Mo. With the addition of Ni, the relative density increased, and thus hardness and bending strength were improved.
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HYDROMETALLURGY
·
2021
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IF 4.156
Yubiao Li,Qihang Xiao,Zhiming Li,Andrea R. Gerson
The slow leaching rate of molybdenite (MoS 2 ), due to its inert nature, and low recovery hinders the application of traditional hydrometallurgical processing. This study investigated the effects of grinding speed and time, molar ratio of sodium chlorate (NaClO 3 , oxidant) to MoS 2 , leaching time and temperature on the leaching efficiency of molybdenum (Mo). Grinding at low speeds via mechanical activation decreased particle size. However, at speeds over 450 rpm for 1.0 h, or at lower speeds but with longer time, it triggers a solid-state reaction (mechanochemistry) producing soluble Na 2 Mo 2 O 7 . This may be due to the existence of an energy threshold for the solid-state reaction. The most suitable activating conditions were 600 rpm for 0.5 h, with a molar ratio of NaClO 3 : MoS 2 = 5, leached in 0.1 M NaOH solution for 2.0 h at 348 K, giving rise to a Mo recovery of 74.8%. The initial acid leaching stage of the ground mixture is dominated by the dissolution of Na 2 Mo 2 O 7 , giving rise to elevated Mo recovery. The later stage is controlled by the dissolution of MoS 2 , slowing down the increase in Mo extraction. As compared to alkaline conditions, acidic leaching of MoS 2 ground at low speeds (non solid-state reaction) gives greater Mo recovery, due to the greater activity of NaClO 3 to MoS 2 under acidic conditions. However, the greatest Mo recovery is achieved in alkaline solution for MoS 2 ground at high speed (solid-state reaction) due to the occurrence of mechanochemical reaction.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Xin Zhou,Haopeng Luo,Bo Sheng,Xingyu Chen,Yihao Wang,Quanyuan Chen,Juan Zhou
The limited production of Cu + in the Cu 2+ /PMS processes constrained its large-scan application for the elimination of organic pollutants . In this study, molybdenum powder (Mo) was applied as the co-catalyst to improve the degradation of 2,4-dichlorophenol (2,4-DCP) in Cu 2+ /PMS system at pH 5.6. By the assistance of Mo, Cu 2+ was rapidly reduced to Cu + which exhibited super activity for the peroxymonosulfate (PMS) activation. Compared with Cu 2+ /PMS processes, the PMS decomposition rate and 2,4-DCP degradation efficiency respectively increased by 62.1% and 83.6% in the Mo co-catalytic Cu 2+ /PMS system after reaction for 20 min. The degradation of 2,4-DCP was completed via both the free radical and non-radical pathways and the free radicals rather than Cu 3+ contributed most to the reaction. In contrast to fresh Mo, the ratio of Mo 4+ increased and Mo 6+ decreased in the used Mo powder, due to the oxidation of Mo 0 by Cu 2+ and/or ∙OH and the reduction of Mo 6+ by O 2 ∙ − . Additionally, the coexistence of Cl - and humic acid with low concentrations showed little effects on the Mo/Cu 2+ /PMS system while HCO 3 − presented an obvious depression for 2,4-DCP degradation. During five cycling runs, all the degradation rates were higher than 92.8%, indicating the good stability of Mo/Cu 2+ /PMS system.
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JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2020
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IF 3.442
Yuting Song,Wencheng Fang,Caixia Liu,Zhixia Sun,Fengyan Li,Lin Xu
Modification of semiconductor materials by polyoxometalates (POMs) is a promising strategy for increasing their photoelectrocatalytic (PEC) activity. In this work, we synthesized POM-modified CdS composite nanocrystals based on three kinds of Keggin-type mixed-addendum Mo/W POMs (Ag 3 PMo 3 W 9 O 40 , Ag 3 PMo 6 W 6 O 40 , and Ag 3 PMo 9 W 3 O 40 ). This is the first report on the semiconductor properties of the three Keggin-type mixed-addendum Mo/W POMs. Their PEC performances were studied by transient photocurrent responses, electrochemical impedance spectroscopy , and PEC oxidation of As(III) to As(V). The PEC performances of POM-modified CdS composite nanocrystals (CdS/Ag 3 PMo 3 W 9 O 40 , CdS/Ag 3 PMo 6 W 6 O 40 , and CdS/Ag 3 PMo 9 W 3 O 40 ) were superior to the performance of pure CdS nanocrystals. CdS/Ag 3 PMo 3 W 9 O 40 composite nanocrystals exhibited the highest efficiency for the PEC oxidation of As(III) to As(V), which was about 85% higher than that of the pure CdS nanocrystals. The present study provides insight into developing novel composite nanocrystals with Keggin-type mixed Mo/W POMs for efficient PEC oxidation.
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