Boosting Tunable Syngas Formation via Electrochemical CO Reduction on Cu/InO Core/Shell Nanoparticles.

In this work, monodisperse core/shell Cu/InO nanoparticles (NPs) were developed to boost efficient and tunable syngas formation via electrochemical CO reduction for the first time. The efficiency and composition of syngas production on the developed carbon-supported Cu/InO catalysts are highly dependent on the InO shell thickness (0.4-1.5 nm). As a result, a wide H/CO ratio (4/1 to 0.4/1) was achieved on the Cu/InO catalysts by controlling the shell thickness and the applied potential (from -0.4 to -0.9 V vs reversible hydrogen electrode), with Faraday efficiency of syngas formation larger than 90%. Specifically, the best-performing Cu/InO catalyst demonstrates remarkably large current densities under low overpotentials (4.6 and 12.7 mA/cm at -0.6 and -0.9 V, respectively), which are competitive with most of the reported systems for syngas formation. Mechanistic discussion implicates that the synergistic effect between lattice compression and Cu doping in the InO shell may enhance the binding of *COOH on the Cu/InO NP surface, leading to the enhanced CO generation relative to Cu and InO catalysts. This report demonstrates a new strategy to realize efficient and tunable syngas formation via rationally designed core/shell catalyst configuration.