Uniform NiPx nanospheres loaded onto defective HxWO3-y with three-dimensionally ordered macroporous structure for photocatalytic nitrogen reduction

Abstract Ammonia synthesis from N2 and water can be achieved at mild conditions utilizing photocatalysis, however the high activation energy for nitrogen coupled with low electron-hole separation efficiency in the photocatalyst results in a low rate of ammonia generation. In this work, a three-dimensional ordered macroporous structure (3DOM) HxWO3-y with oxygen vacancies was constructed, which promoted the activation of nitrogen and increased charge carrier separation, thus improving the photocatalytic nitrogen reduction ability with a value of 7.4 μmol g−1 h−1. The nitrogen reduction ability of 3DOM HxWO3-y was further improved to 34 μmol g−1 h−1 by loading NiPx nanospheres onto the 3DOM structure, which is ∼5 times than 3DOM HxWO3-y. DFT analysis revealed that the oxygen vacancies in HxWO3-y showed higher adsorption activation ability of N2 with the nitrogen reduction reaction (NRR) proceeding in a symmetrical alternating pathway. This study offers a promising route for the N2 fixation using solar energy.