Ni Nanoclusters Anchored on Ni-N-C Sites for CO 2 Electroreduction at High Current Densities.

Transition metal catalyst-based electrocatalytic CO 2 reduction is a highly attractive approach to fulfill the renewable energy storage and a negative carbon cycle. However, it remains a great challenge for the earth-abundant VIII transition metal catalysts to achieve highly selective, active, and stable CO 2 electroreduction. Herein, bamboo-like carbon nanotubes that anchor both Ni nanoclusters and atomically dispersed Ni-N-C sites (NiNCNT) are developed for exclusive CO 2 conversion to CO at stable industry-relevant current densities. Through optimization of gas-liquid-catalyst interphases via hydrophobic modulation, NiNCNT exhibits as high as Faradaic efficiency (FE) of 99.3% for CO formation at a current density of -300 mA·cm -2 (-0.35 V vs reversible hydrogen electrode (RHE)), and even an extremely high CO partial current density ( j CO ) of -457 mA·cm -2 corresponding to a CO FE of 91.4% at -0.48 V vs RHE. Such superior CO 2 electroreduction performance is ascribed to the enhanced electron transfer and local electron density of Ni 3d orbitals upon incorporation of Ni nanoclusters, which facilitates the formation of the COOH* intermediate.