Pivotal role of water vapor- mediated defect engineering on SrTiO 3 nano fi ber toward ef fi cient photocatalytic water splitting

The oxygen vacancies (OVs) have played key roles as either charge carrier traps for inhibiting recombination or directly as active sites for photocatalytic redox reactions. In this study, the population and types of oxygen vacancies within the electrospun SrTiO 3 nanofibers were modulated through water vapor and air atmosphere annealing respectively. Combining the distinctive 1D nanofibrous structure with optimized OVs, the water vapor-mediated OVs-rich SrTiO 3 nanofibers achieved a significant enhancement in specific surface area and porosity, effectively suppressing the recombination of photogenerated carriers. The OVs can effectively promote the conversion of photon excitons into charge carriers, accelerate the carrier separation, and facilitate surface redox reaction. The optimized water vapor-mediated STO-W-70 0 exhibited abundant active sites and rapid surface charge separation/ migration across the nanofibers, leading to an exceptional hydrogen production performance of 296.82 m molg/h. During the photocatalytic process, the OVs act synergistically with nearby metal sites to optimize the adsorption energy of reactants. This work not only provides an effective pathway for manipulating oxygen vacancies through water vapor-mediated defect engineering strategy, but also reveals a new water splitting mechanism, laying the foundation for further research and development of efficient solar energy conversion technologies. (c) 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.