Regulating the Competitive Adsorption of Urea and OH <sup>−</sup> via Brønsted Base Intercalated Nickel Sites for Highly Selective Urea Oxidation
Wenjie Jiang, Jianlong Zhang, Jialin Wu, Zhixiang Zhai, Tianqi Yu, Lin Luo, Shibin Yin
Abstract
Abstract The competitive adsorption of urea and OH − induces undesired oxygen evolution reaction (OER), severely hindering the development of urea electrolysis. Herein, Brønsted base SnO 3 2− intercalated NiOOH (NiOOH─SnO 3 2− ) is constructed through in situ surface reconstruction of intermetallic Ni 3 Sn 2 . The incorporation of SnO 3 2− renders the catalyst surface negatively charged to inhibit OH − adsorption via electrostatic repulsion. Concurrently, theoretical calculations reveal that SnO 3 2− intercalation into NiOOH upshifts the d ‐band center of Ni by stretching Ni─O bonds, thus strengthening urea adsorption. Furthermore, SnO 3 2− in NiOOH increases the conversion energy barrier from * O to * OOH intermediates, inhibiting OER while improving urea oxidation reaction (UOR) activity. Hence, the catalyst almost completely suppresses OER and achieves ≈100% UOR selectivity, reaching a large urea electrolysis current density of 1.0 A cm −2 at a voltage of 1.88 V in the membrane electrode assembly. This study proposes an effective strategy for developing highly selective UOR catalysts by regulating competitive adsorption on active sites.