Organic-Inorganic Hybrid Material for Photocatalytic H₂ Evolution: Electron Shuttling between Photoresponsive Nanocomposite and Co(II) Redox Mediator

In this report, a conductive polymer encapsulated metal oxide photocatalyst is developed through a straightforward insitu synthesis method wherein, polythiophene is incorporated with TiO2 nanoparticles which imparts enhanced visible-light absorption to the samples and significantly improves the efficiency of charge transfer resulting due to the vacancy defects and high conductivity, ultimately leading to exceptional performance in H2 production. Significantly, the rate of H2 production was enhanced even further through the deposition of simple redox mediator. The introduction of Co2+ facilitates the transfer of photogenerated holes from the valence band by its conversion from +2 to +3 oxidation state which further enables the oxidation mechanism. The recombination rate of excitons has been significantly reduced due to the efficient transfer of photogenerated holes and the rate of photocatalytic H2 production is improved. Interestingly, the valence states and local atomic structure of the Ti species in the synthesized sample were ascertained through the utilization of Ti K-edge XANES and EXAFS analysis, which validated the energy position.