| Hydrogen energy is considered to be the cleanest and most promising ways of energy utilization due to its high energy density and non-pollution.Among various hydrogen production technologies,electrochemical water splitting is considered as a hydrogen production technology with zero carbon emission and high product purity.However,due to the high activation energy barrier in the whole reaction process,the voltage required for practical operation is higher than the theoretical voltage,which demands more additional energy consumption.Although noble metal catalysts possess high catalytic activity and can effectively reduce the energy consumption necessary for electrochemical water splitting,their high cost and scarcity hinder their application in practice.Therefore,in order to improve the sluggish kinetics of hydrogen evolution reaction（HER）/oxygen evolution reaction（OER）,low-cost,efficient and stable electrocatalysts should be developed.To obtain ideal electrocatalysts,it is necessary to fully understand the distinct catalytic properties of electrocatalysts and different improvement strategies.This paper is oriented to enhance the intrinsic catalytic activity and stability of catalysts,with bimetallic-based materials,a typical class of alkaline electrolytic water catalysts,as the main research object.A series of bimetallic material precursors were first synthesized in a facile method,and then the electronic structure and intrinsic activity of the catalysts were tuned by introducing heteroatoms and surface interface engineering as the primary improvement strategies.The reaction characteristics of catalyst in the process of water splitting was discussed in depth,and the reaction mechanism was elaborated from the microscopic perspective.The specific research contents of this paper are as follows:（1）Vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes（NiFeP/MXene）were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFeP/MXene exhibited a low overpotential of 286 m V at 10 m A cm-2 and a Tafel slope of 35 m V dec-1 for the OER,which exceeded the OER performance of noble metal catalysts.NiFeP/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm-2.Density functional theory（DFT）calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to optimize the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXene-supported NiFe-based OER catalysts.（2）Polyaniline-coated CoRu-LDH nanoarrays with low loading Ru and regular nanostructures were successfully synthesized.Due to the strong coupling effect and superior intrinsic activity,the as-prepared CoRu-LDH/PANI reached current densities of 0.5 and 1.0 m A cm-2 with overpotentials of only 250 and 275 m V,which were superior thanPt/C and the pure CoRu-LDH.Moreover,the superhydrophilic surface of the CoRu-LDH/PANI allows the immediate evacuation of H2 bubbles during operation at high current density(j=0.5 m A cm-2)due to the regular structure of roughness at both the micro-and nanoscale on the catalyst surface,which makes it possible to maintain optimal stability for up to 50 h.This work provides an new idea for the design of an electrocatalyst that can operate stably at high current densities in alkaline systems. |
