Synthesis And Electrocatalytic Performance Of 2D Transition Metal Nanomaterials

Developing new types of renewable energy is one of the most important mission in the 21st century.Among the various clean energy sources,hydrogen is the most important energy carrier for solving energy crisis.Hydrogen generation from water splitting is an environmentally friendly and efficient energy conversion technology.The entire process does not rely on the traditional fossil energy or emit harmful substances to the environment and such technology can establish the zero-carbon emission system with other renewable energy sources,meeting the sustainable development strategy,which has promising application prospect.Improving the catalytic activity of the electrode material and reducing the overpotential of catalyst in the hydrogen evolution reaction can improve the efficiency of hydrogen production from water splitting,which is the main research direction at present.The surface atoms of the ultrathin two-dimensional nanomaterial can be modified and two-dimensional nanomaterial have large specific surface area which is conducive to enhance the activity of electrochemical catalysts.Therefore,many 2D nanomaterials have been applied in many electrocatalytic reactions.In order to improve the HER catalytic activity.of transition metal materials and reduce the use cost of precious metal materials,we synthesize the ultrathin two-dimensional transition alloy by in situ conversion methods to utilizing the advantages of two-dimensional nanomaterials in hydrogen generation reactions.Such synthesize strategy can enhance the intrinsic activity of transition metal and the active sites on nanosheets structure are fully exposed during catalytic process,leading 2D transition metal nanomaterials exhibit comparable catalytic activity to the state-of-art noble metal based Pt/C catalyst during HER process.Herein,the following two research in this paper provide new ideas for designing efficient two-dimensional transition metal catalysts.1.Using in situ topotactic conversion method reduced the nickel molybdate precursor nanosheet arrays to nickel-molybdenum alloy nanosheet arrays in the liquid phase system,which successful obtained ultrathin two-dimensional nickel-mollybdenum alloy nanosheets for the first time.By regulating the structure on the nanoscale,non-precious metal materials have been effectively modified to improve the catalytic activity in the HER.This superaerophobic Ni-Mo nanosheet array electrode exhibited highelectrochemical activity which is even better than commercial Pt/C catalyst under high current density.2.Using in situ topotactic conversion method reduced the precursor cobalt-iron LDHs to cobalt-iron alloy nanosheet firstly,then made full use of the highly reactive metal atoms cobalt and iron to stabilize the noble metal platinum onto ultrathin layer in low temperature liquid phase environment.Through such synthesize strategy the two-dimensional cobalt-iron-platinum nanosheet with a relative 1%Pt content and highly dispersed catalyst was obtained.The highly dispersed Pt catalyst served as active sites enhanced the HER performance significantly,which is even better than commercial Pt/C catalyst.