Tracking charge transfer pathways in SrTiO3/CoP/Mo2C nanofibers for enhanced photocatalytic solar fuel production

Photocatalytic solar fuel generation is currently a hot topic because of its potential for solving the energy crisis owing to its low cost and zero-carbon emissions. However, the rapid bulk recombination of photoexcited carrier pairs is a fundamental disadvantage. To resolve this problem, we synthesized a dual cocatalysts system of cobalt phosphide (CoP) and molybdenum carbide (Mo2C) embedded on strontium titanate (SrTiO3) nanofibers. Compared with those of pristine SrTiO3 and binary samples, the dual cocatalysts system (denoted SCM) showed a significant improvement in the hydrogen evolution and CO2 reduction performance. Further, the structure of SCM effectively promoted spatial charge separation and enhanced the photocatalytic performance. In addition, the Schottky junction formed between the SrTiO3 and cocatalysts enabled the rapid transfer of photoexcited electrons from SrTiO3 to the cocatalysts, resulting in effective separation and prolonged photoexcited electron lifetimes. The electron migration route between SrTiO3 and the cocatalysts was determined by in situ irradiation X-ray spectroscopy, and band structures of SrTiO3 and the cocatalysts are proposed based on results obtained from UV-vis diffraction reflection spectroscopy and ultraviolet photoelectron spectroscopy measurements. On the basis of our results, the dual cocatalysts unambiguously boosts charge separation and enhances photocatalytic performance. In summary, we have investigated the flux of photoexcited electrons in a dual cocatalysts system and provided a theoretical basis and ideas for subsequent research.