Liu, BotongBotongLiuHuang, LingLingHuangMusho, TerenceTerenceMushoCHIH-JUNG CHENDong, Chung-LiChung-LiDongTang, ChaoyunChaoyunTangYasin, AlhassanAlhassanYasinWang, YuleiYuleiWangYang, HuiHuiYangBright, JoesephJoesephBrightZheng, PengPengZhengRU-SHI LIU2025-04-172025-04-172025-01-0126671107https://www.scopus.com/record/display.uri?eid=2-s2.0-105001845874&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/728192Oxygen vacancies in metal oxide photocatalysts are essential to activate photocatalytic activity toward nitrogen fixation, although their roles and underlying mechanisms remain poorly understood. Unfortunately, oxygen vacancies are prone to disappear during photocatalysis processes. Herein, antimony molybdate (Sb2MoO6) is proposed as a photocatalyst for green ammonia synthesis, which achieves ammonia generation rate of 6.39 μM h−1⋅g−1. Oxygen vacancies modulate the MoO6 octahedra, not the tetrahedral, SbO4 bilayers in the triclinic structure of Sb2MoO6 and result in partial reduction of Mo6+ to Mo5+. Instead of oxygen vacancies themselves, Mo5+ serves as active sites, favoring surface adoption of N2 and formation of reaction intermediates. Oxygen vacancies are predominantly refilled over extended photocatalysis, leading to conversion of Mo5+ back to Mo6+ and consequent photocatalyst deactivation. Therefore, cobalt dopant is introduced to stabilize the oxygen vacancies effectively. The scientific insights obtained will guide the development of stable photocatalysts for green ammonia synthesis. © 2025 Elsevier Inc.enfalseactive sitesgreen ammoniametal oxideoxygen vacancyphotocatalysisSDG13: Climate actionSDG7: Affordable and clean energy[SDGs]SDG7[SDGs]SDG13journal article10.1016/j.checat.2025.1013372-s2.0-105001845874