Catalytic combustion of methane is a promising way of eliminating fugitive methane emissions to meet the rising requirement of the wide application of natural gas vehicles. The performance of catalysts for methane combustion has been found to be significantly affected by the variety of lattice defects, oxygen vacancies, and metal−support interactions which are connected with the category, morphology, and crystal type of both active components and supports. Choices of additives and preparation methods also play important roles in the catalytic combustion of methane. In this Review, we highlight the recent progress in the development and understanding of catalytic combustion of methane. Distinct mechanisms regarding catalytic combustion of methane, including the Langmuir−Hinshelwood mechanism, the Eley−Rideal mechanism, and the Mars−van Krevelen mechanism, are first discussed. The effects of active components, supports, additives, and preparation methods on the properties of catalysts for methane combustion are then analyzed. From a practical point of view, the effects of the components of exhaust gas, which include carbon dioxide, water, sulfur compounds, and nitrogencontaining compounds, are also discussed. Finally, we provide a summary regarding the current situation and future prospects for the catalytic combustion of methane.

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In this work, photothermal synergism over Pd/TiO2 catalysts with varying rutile and anatase phases was investigated for selective catalytic reduction of NO with H2. In the absence of light, two NO x reduction peaks were observed over Pd/TiO2 catalysts. Pd/TiO2-R exhibited better NO x conversion (65 vs 30%) at 75 °C, while Pd/TiO2-A delivered higher activity (82 vs 40%) at 225 °C. Light excitation exerted a more significant promotional effect over Pd/TiO2-R than over the Pd/TiO2-A catalyst. Diffuse reflectance infrared spectroscopy (DRIFTS) with transient experiments indicated that more nitrates and ammonia species formed on Pd/TiO2-R. For Pd/TiO2-R, bridging, mondentate, and bidentate nitrates served as active NO x adsorbed species at all the investigated reaction temperatures. Ammonia species that originated from the reduction of active NO x species were highly active intermediates, which can react with active NO x species to form N2 and H2O. However, for the Pd/TiO2-A catalyst, bridging and monodentate nitrates were active NO x adsorbed species at 75 °C. The reaction pathway at 225 °C facilitates the reaction between adsorbed NO2 and spiltover hydrogen. From the results of valence band X-ray photoelectron spectroscopy (VBXPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS), it could be deduced that the photogenerated holes of both Pd/TiO2 catalysts could activate NO and hydrogen. Moreover, the electrons in the conduction band of the Pd/TiO2-R catalyst had stronger reduction ability, which could combine with O2 to form •O2 –. All these results provided a new insight into the understanding of photothermal synergism in heterogeneous catalysis.