Advances in the Influencing Factors and Reaction Mechanisms of Pd-based Supported Catalysts for Methane Catalytic Combustion

Abstract

Methane (CH4) is a valuable clean energy source, yet it is the second-most significant greenhouse gas following CO2. Given the relatively low CH4 concentration in the atmosphere, its elimination and treatment present considerable challenges. Catalytic combustion technology is currently an effective way to reduce the emission of lean CH4 into the atmosphere. The essential factor for the success of this technology lies in the design and development of efficient catalytic CH4 combustion catalysts. Palladium (Pd)-based supported catalysts have drawn significant attention from researchers because of their excellent low-temperature performance. A deeper comprehension of the various factors affecting the performance of Pd-based supported catalysts and the reaction mechanisms during catalytic CH4 combustion would enable the development of Pd-based supported catalysts with high stability, high activity, and excellent anti-poisoning properties. This study presented a detailed and comprehensive review of the factors that affect the catalytic performance of Pd-based supported catalysts, such as the particle size and oxidation state of Pd species, selection of synergistic components, and the acidity, hydrophobicity, redox performance, and morphology of the carrier. The different reaction mechanisms for catalytic CH4 combustion reactions, including the Mars−van Krevelen (MvK), Langmuir-Hinshelwood (L-H), Eley-Rideal (E-R), and mixed mechanisms, were also explored in detail. Finally, the challenges and future development tendencies of Pd-based supported catalysts in catalytic CH4 combustion were summarized and forecasted.