Ce-doped MoS2-x nanoflower arrays for electrocatalytic nitrate reduction to ammonia

Electrocatalytic reduction of nitrate to ammonia (NO3RR) represents a highly appealing route to achieve both value-added NH3 synthesis and facile removal of waste nitrate. In this study, Ce-doped and S-vacancy-enriched MoS2-x nanoflower arrays are reported as a highly efficient NO3RR catalyst, exhibiting an NH3-faradaic efficiency of 96.6% with a corresponding NH3 yield rate of 7.3 mg h(-1) cm(-2). Theoretical calculations highlight the synergy of the S-vacancy and Ce-dopant to enhance the NO3RR activity of Ce-MoS2-x, in which the S-vacancy-induced unsaturated Mo serves as an active site to activate NO3-, while the Ce-dopant jointly enhances NO3- activation and reduces the thermodynamic energy barrier for the rate-determining step of *NO -> *NOH.