Sinter-resistant Rh nanoparticles supported on γ-Al 2 O 3 nanosheets as an efficient catalyst for dry reforming of methane

• Published in: Nanoscale Vol. 12; no. 40; pp. 20922 - 20932
• Main Authors: Chu, Shasha, Cai, Zhengmiao, Wang, Mingzhi, Zheng, Yanping, Wang, Yongke, Zhou, Zhaohui, Weng, Weizheng
• Format: Journal Article
• Language: English
• Published: 22.10.2020
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/D0NR04644B

γ-Al 2 O 3 nanosheet supported rhodium catalysts with Rh loadings between 0.05 and 2 wt% were prepared by the impregnation method and used for dry reforming of methane (DRM). It was found that Rh species on γ-Al 2 O 3 nanosheets demonstrated excellent stability against sintering at high temperature. After calcining in air at 800 °C followed by reducing with hydrogen at 600 °C, the average particle size of Rh at maximum distribution increases from 1.0 ± 0.3 to 1.8 ± 0.3 nm with an increase in Rh loadings in the catalysts from 0.05 to 2 wt%. Even after reducing with hydrogen at 900 °C, the average size of Rh particles in the catalysts still remained below 2 nm. The results of catalytic performance evaluation show that CH 4 and CO 2 conversions of 84% and 90%, respectively, with a H 2 /CO ratio in syngas close to unity can be achieved with a catalyst of Rh loading of only 0.05 wt% at 750 °C. The performance of the catalyst remains stable for more than 200 h. No significant aggregation of the Rh particles is observed on the catalyst after the reaction. The results of XPS, H 2 -TPR and O 2 -TPD characterization methods indicate that the strong interaction between Rh and the γ-Al 2 O 3 nanosheets plays a key role in increasing the dispersion of Rh species in the catalyst and preventing it from sintering under high temperature conditions. This factor is also responsible for the superior activity and stability of the catalyst with extremely low Rh loading for the DRM reaction.