Hydrophobic Nitrogen-Doped Nanocarbon with Cu-Ni Alloy Sites as a Catalyst for CO2 Electroreduction.

The electrochemical reduction of CO₂ to value-added fuels or chemicals is considered one of the most appealing routes to establish an artificial carbon cycle. In this regard, the design of catalysts with high activity and selectivity in a wide potential window is pursued. Herein, the Cu-Ni alloy/nitrogen-doped nanocarbon (Cu-Ni/NC) with hydrophobicity is synthesized for the electrochemical CO₂ reduction reaction (CO₂RR) through the thermal decomposition of metal-organic frameworks. In the H-cell, the Cu-Ni/NC displays superior selectivity toward CO with a Faradaic efficiency (FE) over 90% in a wide potential window from -0.7 to -1.2 V versus the reversible hydrogen electrode (RHE). Further, a high FE_CO of 98.8% and an impressive CO partial current density (j_CO) of 27.6 mA cm^-2 were achieved at -1.1 V, superior to those of their single metal counterparts. The enhanced CO selectivity may be related to the hydrophobicity, which can suppress the competitive hydrogen evolution reaction. Moreover, in situ ATR-SEIRAS and density functional theory (DFT) calculations reveal that the synergistic effects via intermetal interaction on Cu-Ni(111) surface can facilitate the proton-coupled electron transfer process, and then well balance the formation of COOH* and the CO* desorption. [ABSTRACT FROM AUTHOR]