Artificial Heterointerfaces with Regulated Charge Distribution of Ni Active Sites for Urea Oxidation Reaction

论文题目：Artificial Heterointerfaces with Regulated Charge Distribution of Ni Active Sites for Urea Oxidation Reaction

论文作者：Lei Chen, Lei Wang, Jin-Tao Ren*, Hao-Yu Wang, Wen-Wen Tian, Ming-Lei Sun, Zhong-Yong Yuan*

发表期刊：Small Methods2024, 2400108

Abstract

        In contrast to the thermodynamically  unfavorable anodic oxygen evolution reaction, the electrocatalytic urea  oxidation reaction (UOR) presents a more favorable thermodynamic  potential. However, the practical application of UOR has been hindered  by sluggish kinetics. In this study, hierarchical porous nanosheet  arrays featuring abundant Ni‐WO3 heterointerfaces on nickel foam (Ni‐WO3/NF) is introduced as a monolith electrode, demonstrating exceptional activity and stability toward UOR. The Ni‐WO3/NF catalyst exhibits unprecedentedly rapid UOR kinetics (200 mA cm−2 at 1.384 V vs. RHE) and a high turnover frequency (0.456 s−1),  surpassing most previously reported Ni‐based catalysts, with negligible  activity decay observed during a durability test lasting 150 h. Ex situ  X‐ray photoelectron spectroscopy and density functional theory  calculations elucidate that the WO3 interface significantly modulates the local charge distribution of Ni species, facilitating the generation of Ni3+ with optimal affinity for interacting with urea molecules and CO2  intermediates at heterointerfaces during UOR. This mechanism  accelerates the interfacial electrocatalytic kinetics. Additionally, in  situ Fourier transform infrared spectroscopy provides deep insights into  the substantial contribution of interfacial Ni‐WO3  sites to UOR electrocatalysis, unraveling the underlying  molecular‐level mechanisms. Finally, the study explores the application  of a direct urea fuel cell to inspire future practical implementations.