Solar fuel production from CO₂ reduction in a self-biased hybrid solar-microbial device

Solar-driven carbon-based fuels production is a promising way to store solar energy and alleviate the greenhouse effect. However, current approaches face a lot of challenges, such as poor selectivity, high overpotential, and the requirement of external electrical bias. In this study, based on the photoelectrochemical and bioelectrochemical technologies, we reported a novel self-biased hybrid solar-microbial device, which was capable of converting solar energy into methane without external electrical bias. Owing to the self-generated bias (-0.47 V) from the bioanode and the low overpotential (<50 mV) of the biocathode, the hybrid system demonstrated the conversion from carbon dioxide to methane with a high Faradaic efficiency up to 95.2% and retained a prolonged stability for 30 h using the solar energy as the sole energy input. Moreover, the hybrid system also achieved organic wastewater removal and azo dyes degradation. The development of the hybrid system for solar fuels production can provide a new way to address the increasing demand for renewable energy.