Application Of Local Electric Field Enhancement Effect Of Nanoneedle Arrays In Electrocatalysis

Hydrogen evolution reaction（HER）technology is a promising approach for energy conversion,which can achieve efficient clean energy production.However,the slow kinetics and low conversion efficiency of catalytic reactions limit the energy conversion efficiency.The high curvature structure of the catalyst induces the aggregation of surface charges,inducing a local electric field（LEF）,which enhances the performance by affecting the adsorption or desorption process of reactants.This paper is devoted to the enhancement of LEF caused by the changes of the needle curvature and the needle arrangement and discovers that optimization of needle curvature and arrangement can achieve stronger LEF.HER performance is affected by the attraction or repulsion between LEF and ions.Specific studies are listed as follows:（1）Low curvature Co₃O₄ nanowires（Co NWs）and high curvature Co₃O₄ nano-needles（Co NNs）were prepared to compare the effects of LEF generated by different curvatures on HER performance.The simulation results prove that Co NNs with high curvature structure induce LEF enhancement and cation accumulation.Ion concentration experiments show that compared with Co NWs,Co NNs with high curvature have higher LEF and more increased cation concentration,which could reduce the obstacle of electron transfer and improve HER performance.（2）The ordered and disordered cobalt disulfide（Co S₂）needle arrays were prepared to explore the influence of LEF generated by different arrangements of needles on HER performance.The simulation results show that the LEF intensity on the surface of needle arrays（NAs）is stronger than that of disordered needles（DNs）.In an alkaline environment,a high concentration of OH^-hinders the H₂O dissociation process.Co S₂catalysts with different arrangements were prepared as the model catalyst to regulate the LEF.Ion concentration experiments show that LEF is further enhanced by adjusting the arrangement of needle structures.Depending on the repulsion effect of LEF on OH^-,a local pseudo-acidic environment is constructed around the interface between electrolyte and catalyst surface to further improve HER performance.