Biohybrid Cells for Photoelectrochemical Conversion Based on the HCOO––CO2 Circulation Approach

Biohybrid photoelectrochemical systems could combine the light-harvesting ability of semiconductor photocatalysts and the CO2-processing capability of biocatalysts to realize CO2 reduction. How to develop the energy-utilized model can be of importance for the mechanism exploration of photosynthesis. Here, a biohybrid photoelectrochemical system based on HCOO––CO2 circulation was developed to realize the conversion both of solar-to-electric energy and chemical-to-electric energy. The device consists of a TiO2 nanoparticle photoanode and a laser-scribed graphene/formate dehydrogenase biocathode, which was utilized for the formic acid oxidation and the biocatalysis reduction of CO2 to HCOO–, respectively. The as-proposed biohybrid photoelectrochemical system exhibits good performance with an open-circuit potential of 0.93 V and a maximum power output density of 76 μW cm–2. This ingenious strategy not only exploits a robust carbon circulation system for the conversion of solar energy but also provides a way of constructing complex artificial photosynthesis systems.