Synthesizing Porous Cobalt-Nickel Hydroxide Nanosheets Via Laser Ablation In Liquid For Overall Water Splitting

Water electrolysis the most effective strategy to produce hydrogen and oxygen.It is critical to develop active electrocatalysts for the large-scale production of clean energy.Transition metal hydroxide is the most prospective materials to be widely used in electrochemical catalysis due to their low cost and friendly environment.However,the transition metal hydroxide suffers from inappropriate of intermediates adsorption and the poor electronic conductivity,which cause their poor performance on overall water splitting.Thus,it is urgent to design highly-active catalysis to accelerate the process for HER and OER,simultaneously.Herein,we report the synthesis of cobalt-nickel hydroxide nanosheets with high-density pores via laser ablation in liquid(LAL)process.We found that abundant pores could provide amount of high-active sites and greatly boost the process of HER and OER.The research contents are as follows:1.We,for the first time,prepare porous cobalt-nickel bimetallic hydroxide nanomaterials by LAL,and the optimal catalytic performance was achieved by varying the target material and the laser energy regulation.The existence of nanopores was proved by TEM,BET and BJH analysis.2.The porous nanosheets achieve an overpotential of 235 m V for OER and 95m V for HER at 10 m A cm^-2.The nanosheets were then employed as both OER and HER catalyst for overall water splitting,and the external voltage for water electrolysis is extremely low,merely 1.56 V at 10 m A cm^-2.Our work proves that it is very effective on constructing novel catalyst and creating active sites,and this strategy may be expanded to other two-dimensional materials for obtaining high-performance catalysts.3.The result of XPS indicates that,on the wall of the hole,there is a large number of Co³⁺and Ni³⁺.Moreover,the content of trivalent metal is inevitably related to the number of the pores.Through ingenious comparative experiments and theoretical calculation,Co³⁺has been proved to have higher catalytic activity both in HER and OER catalytic reactions,thus improving the catalytic performance of total water decomposition.Moreover,Ni³⁺shows great conductivity than Co³⁺,which greatly improves the electronic charge.