Hydrogen pressure-assisted rapid recombination of oxygen vacancies in WO3 nanosheets for enhanced N2 photofixation

For the purpose of utilizing the oxygen vacancies (OVs) during the N-2 photo-fixation process, it is of vital importance to develop an efficient method to introduce the substantial OVs in the catalysts. Herein, a simple process of hydrogen pressure re-calcined (HPC) to prepare WO3 photocatalysts with controllable OVs is reported for the first time. During the HPC process, the OVs in WO3 alternated from elimination to recombination quickly. Owing to the more homogeneous distribution of OVs, the re-calcined WO3 samples are demonstrated to be a highly-efficient performance for N-2 photofixation. As expected, the highest NH3 generation rate of optimized WO3 catalyst achieves 150 mu mol.gcal(-1).h(-1), which is about four times higher than the original WO3. This work provides a fresh insight for the catalysts preparation with controllable OVs via the modulation of surface defects for N-2 photofixation.