Dual active site bridging adsorption mechanism of Ni-WO for boosting urea electrolysis at large current density.

Nickel-based catalysts have recently become promising candidates for urea electrolysis. However, their application is hindered by strong interaction with *COO intermediates. Herein, oxyphilic WO is introduced into Ni to construct dual active sites for regulating reaction intermediate adsorption. Experimental results and theoretical calculations reveal that electron transfer from Ni to WO creates electron-deficient Ni, which induces the binding of the -NH group to Ni and anchors the CO group on WO. This site-specific adsorption forms a bridging Ni-NCO-W configuration that lowers the C-N bond cleavage energy barrier. Pathway analysis indicates that *COO intermediates preferentially occupy WO sites while N evolution occurs at Ni sites, thereby enabling coupled desorption and reducing the *COO desorption barrier. Consequently, the optimized catalyst achieves a high urea oxidation reaction (UOR) current density of 1000 mA cm at 1.44 V, which is 2.2 times that of Ni. Meanwhile, it maintains stable operation at 1000 mA cm for 300 h in a membrane electrode assembly. This work provides valuable insights into dual active site engineering for Ni-based catalysts in urea electrolysis applications.