Renewable formate from sunlight, biomass and carbon dioxide in a photoelectrochemical cell.

Pan, Yuyang; Zhang, Huiyan; Zhang, Bowen; Gong, Feng; Feng, Jianyong; Huang, Huiting; Vanka, Srinivas; Fan, Ronglei et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

The sustainable production of chemicals and fuels from abundant solar energy and renewable carbon sources provides a promising route to reduce climate-changing CO<sub>2</sub> emissions and our dependence on fossil resources. Here, we demonstrate solar-powered formate production from readily available biomass wastes and CO<sub>2</sub> feedstocks via photoelectrochemistry. Non-precious NiOOH/α-Fe<sub>2</sub>O<sub>3</sub> and Bi/GaN/Si wafer were used as photoanode and photocathode, respectively. Concurrent photoanodic biomass oxidation and photocathodic CO<sub>2</sub> reduction towards formate with high Faradaic efficiencies over 85% were achieved at both photoelectrodes. The integrated biomass-CO<sub>2</sub> photoelectrolysis system reduces the cell voltage by 32% due to the thermodynamically favorable biomass oxidation over conventional water oxidation. Moreover, we show solar-driven formate production with a record-high yield of 23.3 μmol cm<sup>-2</sup> h<sup>-1</sup> as well as high robustness using the hybrid photoelectrode system. The present work opens opportunities for sustainable chemical and fuel production using abundant and renewable resources on earth-sunlight, biomass and CO<sub>2</sub>.