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

Transition metal catalyst-based electrocatalytic CO 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 electroreduction. Herein, bamboo-like carbon nanotubes that anchor both Ni nanoclusters and atomically dispersed Ni-N-C sites (NiNCNT) are developed for exclusive CO 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 (-0.35 V vs reversible hydrogen electrode (RHE)), and even an extremely high CO partial current density () of -457 mA·cm corresponding to a CO FE of 91.4% at -0.48 V vs RHE. Such superior CO 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.