Electrocatalytic syngas and photocatalytic long-chain hydrocarbon productions by CO2 reduction over ZnO and Zn-based electrodes

• Zn nanorods were grown on Zn support by the hydrothermal method. • Electrochemical CO 2 reduction was performed to produce CO and H 2 with high Faradaic efficiencies. • Syngas ratios were tuned by surface modification, applied potentials, electrolytes, and Pt-deposition. • Direct photocatalytic Fischer–Tropsch synthesis process were observed at ambient temperature. • Alkene-dominant long chain hydrocarbons of C n H 2n and C n H 2n+2 (up to C 7 compounds) were produced. Direct electrocatalytic syngas (CO and H 2 ) production has been attracted as a strategy for energy and environmental solution. Herein, Zn and ZnO nanorod (ZnO NR )-based catalysts were demonstrated to show promising performance in syngas production by electrocatalytic CO 2 reduction. The H 2 /CO ratio was optimally tuned by surface modification, applied potentials, electrolytes, and Pt-deposition. ZnO NR was observed to be commonly reduced to metallic Zn accompanying surface reconstruction during CO 2 reduction. Photocatalytic CO 2 reduction was also tested to observe CO, CH 4 , CH 3 OH, and some organic compounds. We report here a mimic of Fischer–Tropsch (F-T) synthesis can be achieved at ambient temperature by direct photocatalytic CO 2 reduction to produce long chain hydrocarbons of C n H 2n and C n H 2n+2 (up to C 7 compounds). Alkenes were observed to be predominant, compared with alkanes unlike the results reported in the literatures. The very unique results provide valuable information on the development of CO 2 reduction electrocatalysts and photocatalysts for energy and environment.