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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.

Lignin represents the most abundant and sustainable aromatic resource to produce value-added aromatics. However, an efficient and selective cleavage of recalcitrant C–C bonds in lignin under mild conditions remains challenging. Photocatalysis has emerged as a promising strategy for such a C–C bond cleavage under ambient conditions, although the activity and selectivity need to be further improved. Herein, using polyimide as a photocatalyst, we report an efficient and selective C–C bond cleavage in a β-O-4 lignin model under visible light at room temperature. The lignin model was converted into aromatic products with >99% substrate conversion and >99% C–C bond cleavage selectivity, which are superior to previously reported photocatalytic systems. Experimental investigations together with theoretical calculations indicated that the superior performance of the polyimide photocatalyst was attributed to its strong photooxidation capability and efficient charge carrier separation efficiency. Mechanistic studies revealed that the dehydrogenation of the lignin model driven by photogenerated holes was the rate-determining step. This work provides useful guidance for the design of high-performance photocatalysts for selective C–C bond cleavage of lignin.

The aqueous fraction of bio-oil from biomass fast pyrolysis mainly contains low-molecular-weight oxygenates such as carboxylic acids, ketones, aldehydes, phenols, and furans. In this study, the full components of aqueous bio-oil are directionally converted into carbonyl groups such as aldehydes and ketones, and then the oxygen-containing precursors of aviation fuel are prepared through coupling, focusing on exploring the mechanism of carbonylation and C−C coupling. Studies have revealed that propionic acid, furfural, and phenol can be directionally converted into ketones, in which reaction 3-pentanone, cyclopentanone, and cyclohexanone were formed via ketonization and hydrogenation in the aqueous phase. Then the two components of 3-pentanone, cyclopentanone, cyclohexanone, acetone, and acetaldehyde were subjected to aldol condensation to explore the C−C coupling mechanism in the preparation of the C 7 −C 18 precursor of aviation fuel. The mechanism in the high-quality utilization of all components of the aqueous phase bio-oil fraction was explored, which was favorable for the synthesis of biomass-based aviation fuel.

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