Boosting Photocatalytic N ₂ Fixation on N‐Defect g‐C ₃ N ₄ /WO ₃ : the Synergistic Effects of Nitrogen Vacancy and Z‐Scheme Heterojunction

Abstract Photocatalytic nitrogen fixation is a promising strategy for ammonia synthesis under mild conditions by using solar energy, but N 2 activation remains a great challenge. Herein, we demonstrate that a Z‐scheme g‐C 3 N 4 /WO 3 heterojunction possessing abundant nitrogen vacancies exhibits the highly enhanced activity for photocatalytic N 2 fixation through efficient nitrogen molecular activation compared with pristine NVs‐g‐C 3 N 4 and WO 3 photocatalysts. The construction of the internal electric field induced by Z‐scheme NVs‐g‐C 3 N 4 /WO 3 heterojunction allows a rapid charge carrier separation and simultaneously maintains the powerful redox ability of photogenerated charge carriers, defined by the covalent CO bond. Moreover, nitrogen vacancy plays a crucial role in the adsorption/activation of N 2 , which substantially facilitates the hydrogenation to generate NH 3 . According to experimental and theoretical investigations, photocatalytic N 2 fixation on NVs‐g‐C 3 N 4 /WO 3 composites is proposed to be energetically favorable in the alternating pathway. This study offers an alternative way for the design of efficient photocatalysts for photocatalytic N 2 fixation.