Efficient urea electrosynthesis from CO2 and nitrate on amorphous TiS2

Electrosynthesis of urea via co-electrolysis of CO 2 and NO 3 − (EUCN) offers a promising avenue for simultaneously addressing environmental concerns and producing valuable urea. In this study, we report that amorphous TiS 2 (a-TiS 2 ) with rich S-vacancies (S v ) serves as an effective and robust EUCN catalyst. In a flow electrolyzer, a-TiS 2 achieves the maximum urea-Faradaic efficiency of 34.5 % and urea yield rate of 30.6mmol h −1 g cat −1 at −0.7 V. RHE, significantly outperforming crystalline TiS 2 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-S v site to promote *NH 2 /*CO formation and their C N coupling, whilst suppressing the competing hydrogen evolution and NO 3 − -to-NH 3 reactions, thus enabling a highly selective EUCN for urea synthesis.