Sol–gel synthesis combined with solid–solid exchange method, a new alternative process to prepare improved Pd/SiO2–Al2O3 catalysts for methane combustion

Various PdO–support interactions could be obtained on the Pd/SiO2–Al2O3 catalyst prepared by the method adopted in this work. Higher palladium dispersion, lower palladium reduction temperature and better catalytic activity in methane combustion are obtained on the Pd/SiO2–Al2O3 catalyst when PdO–Si interaction is favoured than PdO–Al interaction. In addition, compared to the Pd/SiO2 and the Pd/Al2O3 catalysts, higher catalytic activity is obtained on the Pd/SiO2–Al2O3 solids due to their moderate acidity strength.

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► Pd/SiO2-Al2O3 catalyst is prepared by combining sol-gel and solid-solid exchange.
► PdO-Si interaction is favoured than PdO-Al one on the Pd/SiO2-Al2O3 catalyst.
► Better dispersion and reducibility are obtained when PdO-Si interaction is favoured.
► PdO-Si interaction is more beneficial for methane combustion than PdO-Al one.
► Pd/SiO2-Al2O3 catalysts are more active than Pd/SiO2 and Pd/Al2O3 ones.