Room-temperature liquid metal synthesis of nanoporous copper-indium heterostructures for efficient carbon dioxide reduction to syngas

Nanoporous metals show promising performances in electrochemical catalysis. In this paper, we report a self-supporting bimetallic porous heterogeneous indium/copper structure synthesized with a eutectic gallium-indium (EGaIn) material on a copper substrate. This nanoporous copper-indium heterostructure catalyst exhibits excellent performance in the reduction of carbon dioxide to syngas. The ratio of H2/CO is tunable from 0.47 to 2.0 by changing working potentials. The catalyst is highly stable, showing 96% maintenance of the current density after a 70-h continuous test. Density functional theory calculations reveal that the indium/copper interface induces charge redistribution within the copper surface, leading to the formation of two distinct active sites, namely, Cuδ and Cu0, and enabling a high-performance generation of CO and H2. This work provides a new strategy for obtaining self-supporting nanoporous metal electrode catalysts.