The Two-dimensional Hydroxide Template Constructs A Nitride-based Electrochemical Water Splitting Material

In many energy systems,hydrogen is considered as a clean and sustainable alternative fossil fuels.Electrocatalytic overall water splitting is an important method for preparing high-purity,high-yield hydrogen.In order to speed up the hydrogen evolution reaction?HER?,it is necessary to develop a high-efficiency electrocatalyst.Due to nano-level thickness,high specific surface area and special planar structures,two-dimensional?2D?materials have attracted the attention of researchers.The studies have shown that"holes"on two-dimensional materials can promote the transport of reactants in a direction perpendicular to the layer,thereby further improving its performance.The 2-D sheets can also act“platform”to construct nanohybrids to improve performance.In this thesis,the nitride-based electrocatalyst is constructed on2-D sheet hydroxides for electrocatalytic water splitting.The research contents are as follows:1.Two-dimensional sheet nickel hydroxide?Ni?OH?₂?was selected as the substrate,and ZIF-67 grows in situ on 2D sheet by the interaction of the groups?-OH?with ligand at room temperature,and then further calcined under ammonia atmosphere to obtain porous Ni₃N-Co₃N heterostructure.Experiments show that the presence of Ni species can further promote the transformation of ZIF-67,while the presence of ZIF-67 further inhibits the agglomeration of Ni spicies.Synergistic nitridation of the two results in improved performance.In the 1M KOH,the material has good HER activity,and water splitting performance.2.Two dimensional Ni?OH?₂ and phosphomolybdic acid(PMo₁₂)were selected as nickel and molybdenum sources.The Mo-Ni₃N-MoN composite with 2D porous structure was successfully prepared through the modification method of3-aminopropyltriethoxysilane?KH550?,followed by NH₃ reduction and nitrification.The material prepared by this method has very good HER catalytic activity and great water splitting activity in 1 M KOH alkaline medium.3.Based on the previous research,we found that the composite materials of early transition metal and late transition metal have great advantages in electrocatalysis.Therefore,based on the two-dimensional layer Ni₃Mn₁ LDH,PMo₁₂2 was modified by electrostatic gravitational adsorption,and the Ni-MoN-MnO ternary heterostructure was obtained by nitriding.In 1 M KOH solution,the material has excellent HER activity and good electrocatalytic water splitting activity.