Photocathode engineering for efficient photobioelectrochemical co2 reduction to formate
In this proposal, organic, carbon nanotubes fibres (CNTf) or reduced graphene oxide (RGO),and inorganic, p-type semiconductors or their nanocomposites, nanohybrids are systematically combined in multistep synthetic methods to fabricate novel photocathodes, as well as some counterparts of them (for the purpose of comparison), for studying their efficiency in a photoelectrochemical (PEC) for CO2 reduction to formate. One of the key elements of this hybrid photoelectrode is the presence of the enzyme formate dehydrogenase (FDH) anchored on a highly conductive carbon-based nanomaterial (CNTf or RGO) film at the top of the light absorber that catalyzes the reaction to reduce CO2 to formate. The carbon-based support will provide fast charge transfer from the semiconductor to the biocatalyst, without altering the FDH catalytic center. In other words, for ensuring electron transport between the two key photocathode components), in this project, a carbon nanotube fibre (CNF) or RGO interlayer film will be exploited between the photoactive material and FDH co-catalyst for the first time as a highly conductive platform, which is a prerequisite for technical applications to prevent short-circuiting and leaching of the biocatalyst or mediator species. After evaluation of their PEC activity, the relationship between their structure, synthesis method, and morphology on the one hand and their PEC activity on the another hand will be correlated and discussed. The aim will be selecting the best option as photocathode for designing a photoelectrochemical CO2 reduction reaction (PEC-CO2RR) cell with high efficiency and stability that can alleviate the pollution caused from fossil fuels use. In this way, the design of a photoelectrochemical CO2 reduction reaction (PEC-CO2RR) cell can be accomplished for producing formate, a valuable chemical product due to its wide range of applications.