Abstract: Methane is an important raw material for industrial chemicals. Its efficient and selective conversion into high value-added chemicals via renewable energy is of great significance for achieving sustainable development. Photothermal catalysis breaks through the technical bottlenecks of high energy consumption in traditional thermal catalysis and low conversion rate in photocatalysis, enabling efficient conversion of methane under relatively mild conditions. On the basis of summarizing the mechanisms of photothermal catalysis and reaction devices for methane conversion, this paper focuses on catalytic materials, the core of photothermal catalytic systems. At present, the commonly used catalytic materials in photothermal catalytic systems are mainly divided into four categories: metal oxides, metal sulfides, organic-inorganic hybrid materials and organic semiconductor materials. Among them, metal oxides such as ZnO, TiO₂ and CeO₂ have become the research focus in the field of methane conversion owing to their advantages including high chemical stability, tunable band structure, environmental friendliness and low cost. On this basis, from the perspective of target products, this paper reviews the latest research progress of catalytic materials for photothermal catalytic conversion of methane to produce C₁ products (containing one carbon atom), C₂₊ products (containing two or more carbon atoms), syngas and other products. In terms of strategies to improve catalyst performance, constructing defective structures, loading co-catalytic materials and building composite catalytic systems are mainstream approaches. In view of the insufficient current research on reaction mechanisms, this paper further summarizes mechanism research methods including in-situ characterization, carrier kinetic characterization, theoretical simulation and machine learning, along with techniques such as transient absorption spectroscopy and in-situ infrared spectroscopy. In the future, research on catalytic materials for photothermally catalytic methane conversion will continue to focus on the synergistic improvement of product yield, selectivity and stability through material design. Finally, this paper puts forward prospects for the future development direction of catalytic materials for photothermally catalytic methane conversion.

Key words: photothermal catalysis, methane conversion, methanol, methane coupling, methane reforming, review