材料科学
氧阴离子
电流(流体)
尿素
碳纤维
化学工程
石墨烯
纳米技术
催化作用
有机化学
复合材料
热力学
化学
物理
复合数
工程类
作者
Liqiang Hou,Chaoyue Sun,Zhaoyue Zhang,Haeseong Jang,Zijian Li,Min Gyu Kim,Jaephil Cho,Shangguo Liu,Xien Liu
标识
DOI:10.1002/adfm.202519865
摘要
Abstract Developing cost‐effective electrocatalysts for the urea oxidation reaction (UOR) requires overcoming fundamental limitations of Ni‐based systems: sluggish Ni 2+ /Ni 3+ redox kinetics, competing oxygen evolution, and structural instability. Herein, we demonstrate an organic acid‐assisted electrochemical reconstruction strategy to synthesize carbon‐based oxyanion atomically modified β‐NiOOH nanosheets (Activated NiC 2 O 4 /NF) from nickel oxalate precursors. The in situ embedded oxyanions (‐CO x ) confer triple functionality: 1) enabling direct urea oxidation at ultralow potentials (1.253 V@10 mA cm −2 , 1.357 V@2000 mA cm −2 in 6 m KOH + 0.33 m urea) bypassing NiOOH pre‐formation; 2) suppressing competing OER via a 0.23 eV thermodynamic penalty on the deprotonation evolution step; 3) enhancing lattice oxygen stability by increasing the oxygen vacancy formation energy. This synergy delivers record stability (3000 h@100 mA cm −2 ) and near‐unity N‐product selectivity (>95 ± 2% Faradaic efficiency). In a practical alkaline urea electrolyzer (6 m KOH + 0.33 M urea, 80 °C), it achieves 2000 mA cm −2 at 2.089 V, surpassing state‐of‐the‐art systems. Operando studies and DFT calculations reveal that in situ‐generated oxyanions not only promote UOR via an NH 3 intermediate‐assisted pathway but also inhibit the oxygen evolution reaction by suppressing deprotonation evolution at the active sites. This work establishes a paradigm for anionic‐modification engineering in high‐current‐density electrocatalysis.
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