Rapid Joule-Heating fabrication of oxygen vacancies and anchor of Ru clusters onto BiVO4 for greatly enhanced photocatalytic N2 fixation

Abstract

Herein, we applied a rapid Joule heating method to form oxygen vacancies and further induced the deposition of Ru clusters onto BiVO4. The rapid Joule heating method fabricated oxygen vacancy on BiVO4, resulting in the formation of electron-rich active Ru sites and unsaturated V sites. The pristine BiVO4 was almost no activity in photocatalytic ammonia synthesis. The photocatalytic production rate of ammonia was increased to 3.88 μmol g-1h-1 after the formation of oxygen vacancies, and further increased to 16.57 μmol g-1h-1 with Ru clusters loaded on BiVO4. It was indicated that unsaturated V sites near the oxygen vacancy and Ru clusters might act as the reactive sites for N2 adsorption and activation. And the strong metal-support interactions between Ru and BiVO4 resulted in charge redistribution between Ru clusters and BiVO4 supports, thus reducing energy barrier of the rate-determining step for the N2 hydrogenation. Furthermore, DFT confirmed that associative alternating pathway was suitable for this process.