Interface Engineered V-Zn Hybrids: Electrocatalytic and Photocatalytic CO Reductions.

V-Zn hybrids have widely been used as catalyst materials in the environment and as energy. Herein, V-Zn hybrid electrodes were prepared by the hydrothermal and sputter-deposition methods using a Zn foil support. Their electrocatalytic CO reduction (EC CO RR) performances were tested under various applied potentials, different electrolytes, and concentrations before and after thermal treatment of the demonstrated electrode. Gas and liquid products were confirmed by gas chromatography and nuclear magnetic resonance spectroscopy, respectively. For V-Zn electrode by hydrothermal method produced mainly syngas (CO and H) with tunable ratio by varying applied potential. Minor products include CH, CH, and CH. A liquid product of formate showed a Faradaic efficiency (FE) of 2%. EC CO RR efficiency for CO, CH, and formate was best in 0.2 M KHCO electrolyte condition. CO and formate were further increased by photoirradiation and Nafion-treated electrode. Formate and CH productions were significantly increased by thermal treatment of the V-Zn electrode. CO production was diminished for the V-Zn electrode by sputter deposition but was recovered by thermal treatment. Photocatalytic CO RR was tested to find that RR products include CHOH, CO, CH, CH, and CH. Interestingly long-chain hydrocarbons (CH and CH, where n = 3-6) were first observed under mild conditions. The long-chain formation was understood by Fisher-Tropsch (F-T) synthesis. Alkenes were observed to be more produced than alkanes unlike in the conventional F-T synthesis. The present new findings provide useful clues for the development of hybrid electro-and photo-catalysts tested under various experimental conditions in energy and environment.