Efficient urea electrosynthesis from CO2 and nitrate on amorphous TiS2

Electrosynthesis of urea via co-electrolysis of CO2 and NO3 -(EUCN) offers a promising avenue for simultaneously addressing environmental concerns and producing valuable urea. In this study, we report that amorphous TiS2 (a-TiS2) with rich S-vacancies (Sv) serves as an effective and robust EUCN catalyst. In a flow electrolyzer, a-TiS2 achieves the maximum urea-Faradaic efficiency of 34.5 % and urea yield rate of 30.6mmol h- 1 gcat RHE, significantly outperforming crystalline TiS2 and most reported EUCN catalysts. A combination of extensive atomic characterizations, theoretical computations and in situ spectroscopic measurements reveals the synergistic catalysis of Ti site and Ti-Sv site to promote *NH2/*CO formation and their C-N coupling, whilst suppressing the competing hydrogen evolution and NO3- -to-NH3 reactions, thus enabling a highly selective EUCN for urea synthesis.