Regulation of oxygen vacancies in SrTiO3 perovskite for efficient photocatalytic nitrogen fixation

Photocatalytic nitrogen (N-2) fixation provides a green avenue for the production of ammonia (NH3), which is extremely significant for global biogeochemical cycle. However, there is still lack of highly efficient catalyst to improve the N-2 photofixation efficiency. In this work, oxygen vacancy engineered perovskite SrTiO3 materials have been prepared by post reduction using lithium alkylamine solution and served as effective catalysts for visible-light-driven N-2-to-NH3 conversion. The formation and concentration of oxygen vacancies were confirmed by electron paramagnetic resonance, X-ray photoelectron spectroscopy and thermogravimetric analyses. The SrTiO3 catalyst with optimized oxygen vacancies concentration exhibited improved photocatalytic N-2 reduction rate of 306.87 mu mol.g(-1).h(-1), which is approach ten-fold higher than that of pristine SrTiO3. Electrochemical impedance spectroscopy and photoluminescence measurements reveal that optimum amount of oxygen vacancies can promote the effective adsorption of N-2 molecules and improve the photocatalytic performance by facilitating the fast separation of photo-generated charge carriers. Moreover, the as-fabricated defective SrTiO3 exhibited outstanding stability, which makes it emerge the promising potential for further practical applications. This work offers a feasible method for the design of high performance photocatalysts through defect engineering. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, oxygen vacancy engineered SrTiO3 materials were prepared and found to significantly improve the N-2 reduction efficiency in photocatalysis. Furthermore, an appropriate amount of oxygen vacancies promoted the separation of photo-generated charge carriers, enhancing the photocatalytic performance. The fabricated defective SrTiO3 also exhibited excellent stability, showing promising potential for further applications.