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

Abstract

The sustainable production of chemicals and fuels from abundant solar energy and renewable carbon sources provides a promising route to reduce climate-changing CO₂ emissions and our dependence on fossil resources. Here, we demonstrate solar-powered formate production from readily available biomass wastes and CO₂ feedstocks via photoelectrochemistry. Non-precious NiOOH/α-Fe₂O₃ and Bi/GaN/Si wafer were used as photoanode and photocathode, respectively. Concurrent photoanodic biomass oxidation and photocathodic CO₂ reduction towards formate with high Faradaic efficiencies over 85% were achieved at both photoelectrodes. The integrated biomass-CO₂ 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⁻² h⁻¹ 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 CO₂.

The sustainable production of chemicals and fuels from waste carbon sources holds significant promise for reducing our dependence on fossil resources. Here, the authors demonstrate renewable formate production from biomass wastes and CO2 powered by solar energy.