Enhanced photocatalytic hydrogen generation via novel water gas‑assisted synthesis of CoO/Co3O4 nano-fibers

The development of efficient photocatalysts for renewable hydrogen production via water splitting is of paramount importance for sustainable energy generation. In this study, CoO/Co3O4 nanofibers were synthesized using an innovative water gas-assisted procedure and evaluated as photocatalysts for hydrogen generation from a methanol/water mixture under solar irradiation. The synthesized nanofib-ers exhibited superior photocatalytic activity compared to Co3O4 nanofibers and standard TiO2 nanoparticles, with hydrogen production rates of 66.9, 25.3, and 15.9 mmol H2/gcat·s, respectively. Additionally, the CoO/Co3O4 nanofibers dem-onstrated an anomalous temperature dependence, with hydrogen production rates decreasing from 69.6 mmol H2/gcat·s at 20 °C to 17.76 mmol H2/gcat·s at 50 °C. This unexpected behavior was attributed to the exceptionally high photocatalytic activity of the nanofibers, where increasing temperature led to premature des-orption of reactant molecules from the catalyst surface. These results highlight the potential of CoO/Co3O4 nanofibers as promising photocatalysts for efficient solar-driven hydrogen production and underscore the importance of temperature effects in optimizing photocatalytic systems for renewable energy applications.