Enhanced photocatalytic nitrogen fixation in BiVO4: constructing oxygen vacancies and promoting electron transfer through Ohmic contact

Abstract

The problem of energy crisis promotes the development and utilization of materials related to the application of solar energy. Employing solar energy for clean photocatalytic nitrogen fixation is an effective approach to replace the high-energy consumption Haber–Bosch nitrogen fixation method to alleviate the energy crisis. In this article, mulberry-like BiVO₄ containing oxygen vacancies (OVs–BVO) was prepared by the solvothermal method. In order to further elevate the catalytic effect of the catalyst, Ag nanoparticles with uniform distribution were loaded on the surface of OVs–BVO by the photodeposition method. A variety of survey techniques were performed to characterize the properties of the materials, including XRD, SEM, TEM, Raman, XPS, EPR, DRS, PL and Kelvin probe study. The results show that the subband (defect level) generated by the presence of OVs can accommodate low energy electrons to activate the adsorbed N₂. Ag nanoparticles firmly attached on the surface of OVs–BVO produced a strong local surface plasmon resonance (LSPR) effect, which promoted the utilization of light energy and the effective separation of electron–hole pairs. The electrons have no interfacial barrier to overcome during the transfer between Ag and BVO due to their Ohmic contact. The application of Ag loaded OVs–BVO as a catalyst provides a new direction for the study of catalysts in the field of photocatalytic nitrogen fixation.