Preparation And Electrocatalytic Performance Of Iron-doped NiPS₃-C Nanosheets

Due to its high efficiency and environmental friendliness,electrocatalytic overall water splitting is considered a sustainable technology for producing clean and renewable gaseous hydrogen and Oxygen in large scale.However,since overall water splitting process requires overcoming potentials much higher than theoretical values,the development of efficient,stable and cost-effective electrocatalysts for overall water splitting is essential to advance the prospects of this technology.Transition metal-based electrocatalysts have attracted much attention due to their wide range of raw materials,especially ternary transition metal phosphorus-sulfur?MPS₃?compounds,which has special laminar structure and composition diversity.Despite MPS₃ have been designed for electrocatalysts of water in recent years,and have shown good performance in both HER and OER reactions,at present,most of the synthesis methods are very complicated,which are either time-consuming or energy-consuming,and their poor electrical conductivity is not conducive to the transfer of electrons during catalytic reactions and hinders their further development.Herein,we designed the Ni_xFe_1-x PS-C material to be prepared by using a metal hydroxide grown in situ on a carbon cloth as a precursor through two-step calcination.To modify the synthesis method,we designed materials for the generation of metallic phosphorus-sulfur compounds MPS₃-C?M = Fe,Co,Ni?by one-step phosphor sulphurization with metal hydroxides grown in situ on carbon cloth as precursors,further introduced the element Fe to obtain Ni_xFe_1-x PS₃-C materials.The electrocatalytic decomposition water properties of these two materials were further studied.we prepared Ni_xFe_1-x PS-C nanosheets through a two-step calcination in an argon protected tube furnace of the precursor,Ni_1-xFe_x LDH-C?x = 0,0.05,0.1,1?.In particular,the actual fraction of the Ni0.95Fe0.05PS-C sample was a mixture of Fe doped Ni2 P and Ni17S18.And the Ni0.95Fe0.05PS-C sample exhibited excellent OER activity during the OER test under alkaline conditions,with an overpotential of 239 m V vs.RHE at a current density of 80 m A/cm² and a Tafel slope of 71.5 m V/dec,which is better than most of the currently reported catalysts.Under vacuum-tight conditions,we successfully prepared iron-doped Ni PS₃ nanosheets(Ni_xFe_1-x PS₃-C)through a one-step sulfurphosphidation of the precursor,Ni_1-xFe_x LDH-C?x =0,0.25,0.5,0.75,1?.particularly,the Ni_0.75Fe_0.25PS₃-C sample has a relatively small nanosheet size and a regular arrangement on the carbon fiber,forming a specialthree-dimensional structure,which facilitates the exposure of more active sites and also promotes the diffusion of electrolyte during the catalytic reaction,exhibiting excellent OER and HER activity under alkaline conditions.The Ni_0.75Fe_0.25PS₃-C displays a geometric catalytic current density of 20 m A/cm² at an overpotential of 219 m V vs.RHE and a Tafel slope of 66.5 m V/dec as anode catalytic.In addition,the OER and HER catalytic performance of the Ni_0.75Fe_0.25PS₃-C sample was optimal at high current density.At the same time,the electrochemical activity area test demonstrates that moderate amounts of Fe doping can enhance the intrinsic catalytic activity of the catalyst.