Hollow Nitrogen-Doped porous carbon spheres decorated with atomically dispersed Ni-N3 sites for efficient electrocatalytic CO2 reduction

Hollow nitrogen-doped porous carbon spheres (HNCS) with plentiful coordination N sites, high surface area, and superior electrical conductivity are ideal catalyst supports due to their easily access of reactants to active sites and excellent stability. To date, nevertheless, little has been reported on HNCS as supports to metal-single-atomic sites for CO 2 reduction (CO 2 R). Here we report our findings in preparation of nickel-single-atom catalysts anchored on HNCS (Ni SAC@HNCS) for highly efficient CO 2 R. The obtained Ni SAC@HNCS catalyst exhibits excellent activity and selectivity for the electrocatalytic CO 2 -to-CO conversion, achieving a Faradaic efficiency (FE) of 95.2% and a partial current density of 20.2 mA cm −2 . When applied to a flow cell, the Ni SAC@HNCS delivers above 95% FE CO over a wide potential range and a peak FE CO of 99%. Further, there is no obvious degradation in FE CO and the current for CO production during continuous electrocatalysis of 9 h, suggesting good stability of Ni SAC@HNCS.