Photocatalytic CO Reduction to Ethanol by ZnCoO/ZnO Janus Hollow Nanofibers.

Photocatalytic carbon dioxide (CO) reduction for high-value hydrocarbon fuel production is a promising strategy to tackle global energy demand and climate change. However, this technology faces formidable challenges, primarily stemming from low yield and poor selectivity of C2 products of the desired hydrocarbon fuels. This study reported ZnO/ZnCoO Janus hollow nanofibers (ZnO/ZCO JHNFs) prepared by electrospinning and atomic layer deposition. Photocatalytic tests revealed an ethanol yield of 4.99 μmol g h for ZnO/ZnCoO JHNFs, surpassing mixed ZnO/ZnCoO nanofibers (ZnO/ZCO NFs) by 4.35 times and pure ZnO by 12.7 times. The selectivity of 58.8% is 2.38 and 4.49 times higher than those of ZnO/ZnCoO NFs and ZnO, respectively. These enhancements are attributed to efficient carrier separation facilitated by the ordered internal electric field of the Z-scheme heterojunction interface, validated by the energy band evaluations from experimentation and density functional theory (DFT) simulations and charge separation characterizations of photocurrent, impedance, and photoluminescence spectra. The Janus structure also effectively exposes the surface of ZnCoO to CO molecules, increasing the active site availability, as confirmed by BET nitrogen adsorption/desorption, temperature-programmed desorption tests, and DFT adsorption energy calculations. This study proposes a novel approach for efficient photocatalytic hydrocarbon fuel production, with potential applications in energy and climate crisis mitigation.