The critical role of amorphous oxygen in low-temperature catalytic oxidation of H₂S: Performance and mechanisms.

Authors

Mengxue Yin, Hailong Wang, Fanhao Song, Xiaojian Zhou, Min Zhou, Yuan Wei, Fengchang Wu

Published in

Journal of hazardous materials. Volume 515. Pages 143084. Jul 23, 2026. Epub Jul 23, 2026.

Abstract

Transition metal-modified Cu-based catalysts have attracted interest for H₂S catalytic desulfurization, yet the roles of oxygen species and transition metal promoters in radical-mediated mechanisms remain unclear. Here, Cu-based catalysts modified with ZnO, NiO, or Fe₂O₃ were synthesized and evaluated via dynamic desulfurization experiments, multi-technique characterization, and DFT calculations. Although the three samples generated abundant ·OH species, Fe₂O₃/Al₂O₃ exhibited negligible desulfurization activity, whereas NiO/Al₂O₃ and ZnO/Al₂O₃ showed notable catalytic performance. Multi-technique characterization confirmed that amorphous oxygen in the disordered structure induced by Cu/Ni/Zn oxide doping is indispensable for the ·OH-driven reactions; without it, no catalytic desulfurization occurred. ZnO and NiO promoted Cu²⁺ → Cu⁺ reduction, increased oxygen vacancies (VOs) concentration, enhanced ·OH content, and created moderate-strength basic sites, collectively facilitating the efficient oxidation of HS^- by ·OH anchored on the amorphous oxygen. In contrast, although Fe₂O₃ doping more effectively enhanced the ·OH content in Cu-based catalysts, it reduced the amorphous oxygen content and its strong H₂S affinity blocked the active Cu sites, thereby suppressing catalytic activity. This work establishes that high desulfurization efficiency requires the simultaneous optimization of the four factors: the sufficient amorphous oxygen, the high VOs concentration, the abundant ·OH, and the appropriate basic sites, while avoiding dopants with excessive H₂S adsorption strength. These insights provide a rational design framework for non-structured, radical-driven desulfurization catalysts operating under ambient conditions.

PMID:
42537297
Bibliographic data and abstract were imported from PubMed on 01 Aug 2026.

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