Artificial photosynthesis using solar energy is an important process to reach carbon neutrality and the resulting chemicals can be referred to as solar fuels. This report presents our research progress in optimizing solar energy-driven CO2 reduction. We have developed a novel method for the controlled construction of active sites based on vacuum preparation conditions. The method is based on a dynamic deposition-etch-bombardment process of high-energy Cu atoms, which enables controlled exposure of Cu(100) facets without the use of capping agents. Using a gas diffusion layer as the substrate, Cu(100)-rich electrodes can be obtained in one step without an additional catalyst loading step. The Faradaic efficiency of ethylene is 58.6% at –0.75 volts vs. reversible hydrogen electrode, and the full-cell electrical energy conversion efficiency corresponding to the C2+ products is 36.5%. In addition, coupling this electrode to a commercialized monocrystalline Si solar cell achieves 6.0% efficiency of solar energy conversion to C2+ products. Utilizing in situ infrared spectroscopy assisted by theoretical calculations, we further resolved the effect of Cu facets on the C-C coupling barrier. To boost the efficiency of ethylene production, we designed a membrane electrode assemble reaction system that does not require a liquid cathode electrolyte. Through regulating the multi-physical fields such as temperature, velocity, and pressure inside the device, we can achieve up to a single pass yield of 13.2% at a total current of 12 A. The results obtained from this study provide new ideas for the design of reaction systems for artificial photosynthesis.

Catalyst and device engineering for efficient solar fuel production

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.