Preparation And Catalytic Performance Of Molybdenum-based Electrocatalysts

Molybdenum-based electrocatalysts are regarded as one of the candidate materials to replace precious metal catalysts because of their relatively low cost and excellent catalytic performance.Using the narrow pores of porous carbon to limit the size of molybdenum-based catalyst is expected to improve its catalytic performance,and its confinement effect can effectively prevent the aggregation and loss of catalyst during the catalytic process,which can improve its catalytic stability.In view of this,molybdenum single atomic catalysts,nano-molybdenum carbide and molybdenum phosphide catalysts were prepared respectively by using high content nitrogen-doped porous carbon and mesoporous carbon,and probed their electrochemical oxygen reduction and hydrogen evolution properties in this dissertation.The main contents are as follows:?1?Previous studies have shown that metallic molybdenum is not an ideal electrocatalyst for oxygen reduction.In order to improve its performance,this dissertation used high content nitrogen-doped porous carbon to effectively anchor the molybdenum element,and successfully prepared a molybdenum single atom catalyst?Mo SAs/N-C?as an oxygen reduction electrocatalyst.Performance tests show that the molybdenum single atom catalyst has excellent electrocatalytic oxygen reduction activity,and has better methanol resistance and stability than commercial Pt/C?20%?.The results of the study confirmed that when the size of the metal material is small to the atomic level,its catalytic activity will undergo a qualitative mutation,proving that single atomization is an effective method to improve its catalytic performance.?2?A carbothermal reduction method was developed to prepare Mo₂C@CMK-3 catalyst using a mesoporous carbon?CMK-3?as the support.Making full use of the narrow channels of CMK-3,the size of Mo₂C was controlled to about 5 nm for the electrocatalytic hydrogen evolution reaction.The results show that the optimal Mo₂C@CMK-3 has higher electrocatalytic performance than CMK-3 and unsupported Mo₂C particles,confirming that the restriction of CMK-3 is an important means to enhance catalytic activity.?3?Based on the previous work,Mo P@CMK-3 catalyst was prepared by introducing diammonium hydrogen phosphate as a phosphorus source in the reaction system.The narrow pores of CMK-3 were used to control the size of Mo P to about 8 nm for electrocatalytic hydrogen evolution reaction.The results show that the optimal Mo P@CMK-3 has higher electrocatalytic performance than CMK-3 and unloaded Mo P particles,which further confirms that the restriction of CMK-3 is an important method to enhance catalytic activity.