有机配体表面改性NiCo2O4纳米线用于水全分解

Surface Modification of NiCo2O4 Nanowires using Organic Ligands for Overall Water Splitting

由于水分解在绿色能源领域的重要作用,能够在碱性介质中进行析氢(HER)和析氧(OER)反应的双功能电催化剂具有重要的应用价值。本文报道一种具有丰富缺陷的表面改性NiCo_(2)O_(4)纳米线(NWs),在碱性介质中作为一种高效的整体水裂解电催化剂。X射线光电子能谱(XPS)分析表明,Co^(2+)/Co^(3+)比值的增加是表面修饰NiCo_(2)O_(4)纳米线具有优异双功能电催化性能的重要原因。结果表明,在1.0 mol·L^(−1)KOH溶液中,通过有机配体主导的表面改性,优化后的NiCo_(2)O_(4)纳米线在电流密度达到10 mA·cm^(−2)时的HER过电位仅为83 mV,OER过电位仅为280 mV。更重要的是,有机配体表面改性后的NiCo_(2)O_(4)纳米线表现出了出色的水分解性能,在2.1 V电压下达到了100 mA·cm^(−2)的电流密度。目前的工作凸显了提高NiCo_(2)O_(4)NWs尖晶石结构中Co^(2+)含量对促进整体水裂解的重要性。

Bifunctional electrocatalysts in alkaline media play an important role in the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),owing to the considerable influence of water splitting in the green energy sector.Herein,we present surface-modified NiCo_(2)O_(4) nanowires(NWs)with rich defects as a highly efficient overall water splitting electrocatalyst in alkaline media,where the surface modification is accomplished using organic ligands.X-ray photoelectron spectroscopy reveals that the increase in the Co^(2+)/Co^(3+) ratio is responsible for the excellent bifunctional electrocatalytic performance of the surface-modified NiCo_(2)O_(4)NWs.As expected,benefiting from the organic ligand-dominated surface modification,the optimized NiCo_(2)O_(4)NWs can display an overpotential of only 83 mV for the HER and 280 mV for the OER,with a current density of 10 mA·cm^(−2)in 1.0 mol·L^(−1)KOH solution.More importantly,the NiCo_(2)O_(4)NWs surface-modified using organic ligands exhibit outstanding performance for overall water splitting,with a voltage of 2.1 V and current density of 100 mA·cm^(−2),and also maintain their activity for at least 15 h.The present work highlights the importance of increasing the content of Co^(2+)in the spinel structure of NiCo_(2)O_(4)NWs for enhancing their performance in overall water splitting.