(Invited) Promoted Nitrogen Photofixation over Periodic WS2@TiO2 Nanoporous Film

Abstract

Atmospheric nitrogen fixation using a photocatalytic system is a promising approach to produce ammonia. However, most of the recently explored photocatalysts for N2 fixation are in powders, which suffer from particle agglomeration, difficulty in the collection, and unsatisfied conversion efficiency. To the best of our knowledge, rare research about the N2 photofixation over periodic nanostructured films has been reported. Compared with the powdered photocatalysts, the film materials have the inherent advantages over powders, including but not limited to easy transportation and collection. Moreover, the periodic nanostructured films are beneficial for providing photogenerated charge carriers with short diffusion length and favorable transport pathways, leading to superior photocatalytic performances. In this work, we reported the efficient photofixation of N2 over a periodic WS2@TiO2 nanoporous film, which was fabricated through a facile method combing anodization, E-beam evaporation and chemical vapor deposition (CVD). Oxygen vacancies were introduced into the TiO2 to improve the N2 adsorption and activation. The as-prepared WS2@TiO2 film with an optimized WS2 content shows highly efficient photocatalytic performance for N2 fixation with an NH3 evolution rate of 1.50 mmol g-1 h-1, representing one of the state-of-the-art catalysts. This study aims to explore efficient film materials for not only N2 photofixation but also other solar energy conversion applications.