In Situ Photo-Fenton-Like Tandem Reaction for Selective Gluconic Acid Production from Glucose Photo-Oxidation

Biomass photorefining to selectively produce value-added bioproducts is an emerging alternative biomass valorization approach to alleviate energy crisis and achieve carbon neutrality. Here, we demonstrate an efficient and selective glucose photo-oxidation to gluconic acid via a rationally designed dual-functional carbon nitride photocatalyst that not only allows H2O2 production via 2e- oxygen reduction reaction (2e-ORR) but also realizes in situ photo-Fenton-like reaction. As a result, the essential oxidative species (•O2- and •OH) for glucose oxidation into gluconic acid are generated that achieves >60% glucose conversion and >60% of gluconic acid selectivity within 4 h. Density functional theory calculations demonstrate the superior performance of the photocatalyst for •O2- and H2O2 generation. Further experimental results reveal that the moderate concentration of H2O2 produced by 2e-ORR reaction plays a vital role in regulatinge gluconic acid selectivity. This work demonstrates a good example to realize selective biomass photorefining through tandem reaction of ORR and in situ photo-Fenton-like process, which could have profound impact on artificial photoenzyme systems involving moderate H2O2 modulation.