Bismuth nanoparticles and oxygen vacancies synergistically modified HNb3O8 nanosheets for enhanced photocatalytic N2 reduction towards NH3.

A Bi/HNb 3 O 8 -Vo hybrid photocatalyst was designed by a simple two-step method. Through the synergistic effect of oxygen vacancies and Bi nanoparticles on the catalyst surface, the electron-hole complexation rate was reduced, and the adsorption and activation of N 2 was enhanced. [Display omitted] Due to the high stability of the N 2 molecule and the low charge separation efficiency, the photocatalytic reduction of N 2 to high-value chemicals (NH 3) under mild conditions remains a great challenge. Herein, a composite photocatalyst (Bi/HNb 3 O 8 -Vo nanosheets) with Bi nanoparticles modified the HNb 3 O 8 -Vo nanosheets are designed for the conversion of N 2 into NH 3. In this design, the introduction of oxygen vacancies on the catalyst surface facilitates the formation of defective energy levels within the band gap of HNb 3 O 8 -Vo NS, which promotes the absorption of visible light, and enhances the charge carrier transport and separation. Bi nanoparticles co-catalyst not only facilitates the separation and migration of photogenerated charges, but also acts as reaction sites to adsorb and activate N 2 molecule. Consequently, the optimized 5 % Bi/HNb 3 O 8 -Vo photocatalysts show a NH 3 yield of 372.7 μmol/L g−1h−1 under full spectral irradiation without sacrificial agent, which is much higher than that of HNb 3 O 8 NS (92.2 μmol/L g−1h−1). This work provides a new way for the design of efficient N 2 reduction photocatalysts through the synergistic effect of surface vacancies and metal co-catalysts. [ABSTRACT FROM AUTHOR]