ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Electron transfer-driven low-temperature catalytic oxidation of low-concentration methane over Rh_x/CrO_y composite oxides

Mengtao Liu, Yan Lv, JiaYang Wu, Yuanyuan Meng, Qinbo Yuan, Jiakui Pan, Chuanmin Ding, and Junwen Wang

Shanxi Key Laboratory of Chemical Product Engineering, College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan, People’s Republic of China

E-mail: dingchuanmin@tyut.edu.cn

Received: 15 February 2026  Accepted: 18 May 2026

Abstract:

To mitigate environmental issues associated with low-concentration methane emissions (< 1%) from coal mine ventilation air methane. This study employed a one-pot sol–gel synthesis to prepare amorphous Rh/Cr oxide catalysts with varying Rh doping levels (0.05 to 0.5 wt%). The aim was to systematically investigate the correlation between Rh content, the catalysts' physicochemical properties, and their performance in methane oxidation. The Rh_0.3/CrO_y catalyst has been demonstrated to achieve a methane conversion rate as high as 90% at a reaction temperature of 448 °C. The results indicate that after calcination, a highly dispersed oxide structure Rh/CrO_y was formed, accompanied by the generation of a certain concentration oxygen vacancies. These vacancies provide structural support for electron transfer between the two metals. The Rh_0.3/CrO_y catalyst exhibited optimal catalytic activity at low temperatures. Characterization analysis reveals that the construction Rh-Cr bonds acting as charge transfer donors and acceptors, while modulation of oxygen vacancy concentration synergistically enhances the redox kinetics on the catalyst surface. However, high Rh loading (> 0.3 wt%) decreased activity due to particle aggregation.

Keywords: Cr-based catalysts; Rh-doped; Methane oxidation at low concentration; Charge transfer; Oxygen vacancies

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05079-8

Chemical Papers 80 (10) 11621–11632 (2026)