Oxygen vacancy-rich MoO3-x nanobelts for photocatalytic N-2 reduction to NH3 in pure water

Photocatalytic nitrogen fixation is a promising sustainable and green strategy for NH3 synthesis. The development of an efficient photocatalyst is the key to make this approach applicable. In this work, MoO3-x nanobelts are synthesized by a hydrothermal method, and they are firstly utilized as photocatalysts for N-2 fixation without using sacrificial reagents and precious-metal co-catalysts at room temperature and atmospheric pressure. It is found that oxygen vacancies (O-VS) are located on the (001) and (100) planes by STEM analysis. The surface O-VS can chemisorb the N-2 molecules by a side-on model on (001) while an end-on model on the (100) plane and elongate their bond length, playing a critical role in the photocatalytic N-2 fixation activity. This result provides a new insight into developing efficient photocatalysts with original oxygen vacancies.