Oxygen-vacancy-mediated photocatalytic activity of antimony molybdenum oxide toward green ammonia synthesis
Journal
Chem Catalysis
Start Page
101337
ISSN
26671107
Date Issued
2025-01-01
Author(s)
Liu, Botong
Huang, Ling
Musho, Terence
Dong, Chung-Li
Tang, Chaoyun
Yasin, Alhassan
Wang, Yulei
Yang, Hui
Bright, Joeseph
Zheng, Peng
Abstract
Oxygen 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.
Subjects
active sites
green ammonia
metal oxide
oxygen vacancy
photocatalysis
SDG13: Climate action
SDG7: Affordable and clean energy
Publisher
Cell Press
Type
journal article