【Frontiers in HaiChuan Chemical Technology】Dalian Institute of Chemical Physics uncovers the essential characteristics of active sites in high-performance platinum-based methane combustion catalysts

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I have revealed the essential characteristics of the active sites in high-performance platinum-based methane combustion catalysts. Publication date: 2025-06-13 | Submitted by: Group DNL0901 | [Enlarge] [Shrink] | [Print] [Close] Recently, a team led by researchers Wang Shudong, Wang Sheng, and assistant researcher Zong Xupeng from the Energy and Environment Engineering Research Center (Group DNL0901) within the Department of Energy Conservation and Environmental Research at our institute has made new progress in the development of platinum (Pt)-based methane combustion catalysts. They designed and developed a highly active, sulfur-resistant Pt-based supported methane combustion catalyst, and also uncovered the mechanism by which methane is adsorbed and activated at the active sites of this catalyst. Catalytic combustion technology is widely used to purify volatile organic compounds (VOCs), coke oven flue gas, carbon monoxide (CO) gas from industrial furnaces, and low-concentration waste gas. The active component of traditional methane combustion catalysts is the precious metal palladium (Pd), but it becomes deactivated very easily due to sulfur poisoning. Although Pt-based catalysts exhibit excellent sulfur tolerance in catalytic combustion processes involving CO and VOCs, their methane activation capacity is weak; therefore, it is imperative to enhance their catalytic oxidation activity for methane in order to meet the demands of methane purification applications. In this work, the team designed and synthesized a platinum/tin oxide (Pt/SnO2) catalyst that enables efficient catalytic purification of methane, addressing the reliance on Pd metal and the issue of sulfur poisoning in methane catalytic combustion. Studies have found that the Pt atoms supported on SnO2 exhibit a unique cluster packing configuration and an electron-deficient state. In-situ characterization and density functional theory calculations show that this unique geometric and electronic structure enables the Pt site to undergo strong electronic coupling with methane molecules; it can \"seize\" the electrons from the C-H bonds in methane and \"inject\" them into the Pt dz2 empty orbital, resulting in the lengthening of one of the C-H bonds in the methane molecule (to 1.22 Å). This mechanism enhances the chemical adsorption and activation capacity of the Pt active center for methane, and enables a redox cycle upon the supply of molecular oxygen. This catalyst exhibits excellent low-temperature activity, stability, and resistance to sulfur poisoning: at an space velocity of 60,000 ml gcat-1 h-1, the temperature for 90% conversion of methane combustion (T90) is as low as 390°C ； At 500°C, the catalyst operated stably for over 20 hours under sulfur-containing conditions of 30 ppm SO₂, with an activity degradation of less than 1%. This team has been dedicated for a long time to fundamental research on the application of catalytic purification technologies for air pollutants, as well as to process development and system integration. The catalytic combustion technology they developed has been widely used in the field of VOCs purification. In recent years, the team has also carried out a series of applied fundamental studies on the development of sulfur-tolerant catalysts, including CO synergistic purification (ACS Catal., 2024) and catalytic oxidation of methane (Chem. Eng. J., 2020).