Electron Withdrawal from Methane by Pt Atoms on Stannic Oxide for Highly Active Low-Temperature Combustion
Ran Wang, Guobo Li, Xupeng Zong, Jiaxing Wang, Yuanjie Xu, C. H. Jin, Mingzhe Wang, Peijie Ma, Rui Zhang, Kun Zheng, Jiangliang Hu, Junjie Liao, Jiancheng Wang, Yu Tang, Yihu Dai, Shudong Wang, Shudong Wang, Sheng Wang, Sheng Wang
Abstract
Supported Pt catalysts often exhibit limited effectiveness in achieving complete methane oxidation, which restricts their commercial application. However, Pt catalysts are particularly attractive, especially in sulfur-containing environments, where commercial Pd catalysts are more susceptible to sulfur poisoning. Therefore, developing highly active Pt sites and gaining a deeper understanding of the intrinsic mechanisms governing methane combustion over Pt catalysts is essential. In this study, we present a highly active stannic oxide supported platinum catalyst (Pt/SnO 2 ) for stable low-temperature methane combustion, achieving a T 90 as low as 390 °C at a high gas hourly space velocity (GHSV) of 60,000 mL·g cat –1 ·h –1 . This performance surpasses that of most other Pt catalysts as well as Pd/SnO 2 and benchmark Pd/Al 2 O 3 . The superior SO 2 tolerance of Pt/SnO 2 was demonstrated by the stability of methane conversion at 500 °C, with only a minor reduction observed during the long-term online test. Characterization results indicate that the Pt atoms on SnO 2 are electron-deficient and predominantly adopt a crowded configuration. In situ studies and density functional theory (DFT) calculations reveal that the electron-deficient, crowded Pt atoms enhance the chemisorption of CH 4 molecules by withdrawing the electrons from CH 4, resulting in activated CH 4 with an elongated C–H bond. This work provides an in-depth understanding of the nature of Pt active sites for high-performance methane combustion, offering valuable insights for the rational design of Pt-based catalysts.