Activating La−O−Ni Bridge in Ordered Macroporous Interface for Electrochemical Urea Wastewater Purification
Xiao‐Yue Qiang, Yaxiong Yao, Jie Yin, Pengfei Da, Zhaori Mu, Kaier Shen, Yuanmiao Sun, Yunxiang Zhang, Peiqiong Li, Zhenglong Li, Pinxian Xi, Chun‐Hua Yan
Abstract
Abstract Electrochemical treatment of urea wastewater purification significantly aids in environmental protection, but it remains a considerable challenge in designing high performance anode urea oxidation electrocatalysts. Herein, we report a La‐induced three‐dimensional ordered macroporous (3DOM) NiO heterostructure to improve Ni sites electron density for urea electrooxidation by activating the La−O−Ni bridge. This material demonstrated exceptional performance in a membrane electrode assembly (MEA) device, characterized by a low cell voltage (1.49 V @ 80 °C) and 280 h stability test at 1 A cm −2 current density (25 °C) and displayed promising efficiency in urea wastewater purification. Permeation experiments revealed the crucial role of 3DOM morphological in facilitating mass transfer processes. A high valence nickel mechanism (HNM) on the La−O−Ni bridge during catalysis was proposed, based on various in situ characterizations and theoretical calculations. Experimentally, in situ Raman and UV‐vis spectra demonstrated that Ni active species Ni δ+ (δ≥3) promote urea oxidation kinetics, while in situ ATR‐IR proved strong adsorption of C=O with Ni sites and the enhancement of urea N−H bonds cleavage, supporting the HNM. This work enables us to underscore the critical importance of La−O−Ni electron bridge with 3DOM architectures and promising contributions to urea wastewater purification.