钼-钴-钒多金属复合材料设计及碱性电解水制氢性能

Design and Performance of Molybdenum-Cobalt-Vanadium Polymetallic Composite Materials for Hydrogen Production by Alkaline Water Electrolysis

为制备高效碱性电解水催化剂,先通过水浴共沉淀法在80℃下反应4 h获得钴钒双金属氧化物基底,再通过在200℃下反应8 h负载含钼化合物制得钼-钴-钒多金属复合材料Co_(2)V_(2)O_(7)@MoS_(2)。该复合材料的微观形貌和物相分析表明,钴钒双金属氧化物基底为六边形片状形貌,表面负载的含钼化合物为纳米片状且呈现无定型结构。电化学测试结果表明,所得钼-钴-钒多金属复合材料Co_(2)V_(2)O_(7)@MoS_(2)-8在驱动电解水阳极析氧反应中表现出优异的电催化活性,当驱动电流密度为10 mA/cm2时,所需过电势为241 mV,相较于单独组分Co_(2)V_(2)O_(7)和MoS_(2)分别提升29.1%和22.8%。此外,Co_(2)V_(2)O_(7)@MoS_(2)-8材料在进行80 h恒电流密度测试后,过电势降低3.8%,表明该复合材料具有良好的长寿命循环稳定性。Co_(2)V_(2)O_(7)@MoS_(2)复合材料催化活性的提升,与其本身的界面结构有关,内部丰富的微孔通道和界面异质结均有利于界面电子的快速传递,最终加速碱性电解水的动力学过程。

In order to prepare an efficient alkaline water electrolysis catalyst,a water bath co-precipitation method was used to acquire cobalt-vanadium bimetallic oxide substrate reacted at 80℃for 4 h,and then the molybdenum-bearing compounds were loaded on this substrate to form molybdenum-cobalt-vanadium polymetallic composite Co_(2)V_(2)O_(7)@MoS_(2)under the condition of 200℃for 8 h.Based on results of the microstructure and phase analysis of the composite material,the morphology of Co_(2)V_(2)O_(7)substrate is hexagonal flake and that of the loading MoS_(2)is nano-flake which has an amorphous structurewere discovered.Results of the electrochemical test disclosed that the molybdenum-cobalt-vanadium polymetallic composite Co_(2)V_(2)O_(7)@MoS_(2)exhibits an excellent electrocatalytic activity in the oxygen evolution reaction.It requires an overpotential of 241 mV to drive a current density of 10 mA/cm2,increasing by 29.1%and 22.8%efficiency over the individual component of Co_(2)V_(2)O_(7)and MoS_(2),respectively.In addition,the overpotential of Co_(2)V_(2)O_(7)@MoS_(2)-8 decreased by 3.8%after a long-term electrolysis of 80 h with a constant current density,indicating the composite materials possess a great long-life cycle stability.The improved catalytic activity of Co_(2)V_(2)O_(7)@MoS_(2)is correlated with its interface structure.Both the abundant internal microporous channels and interfacial heterojunction are conductive to the rapid transfer of interfacial electrons,and further accelerate the kinetic process of alkaline water electrolysis.