Participation of sulfates in propane oxidation on Pt/SO42−/CeO2–ZrO2 catalyst

The platinum catalysts supported on CeO2–ZrO2(CZ) and SO42−/CeO2–ZrO2 (SCZ) were studied for the reaction mechanism of propane total oxidation in an oxygen-rich atmosphere. The propane oxidation activity of Pt/CZ is greatly improved after sulfate addition. The catalysts were characterized by XRD, BET, IR spectra of CO adsorption as well as IR spectra of C3H8 adsorption and oxidation. The specific surface area of the sulfated catalyst decreases from 40 to 14 m2/g by the blocking effect of surface sulfates, and no obvious structure change is observed according to the XRD results. The spectra of CO adsorption indicate that Pt is on a more electronic-deficient state due to the electronic withdrawing effect of sulfates. Some more active sites are suggested to be generated at the interface of platinum and sulfates according to the activation energy calculation. The formation of such interfacial active sites plays an important role in CH cracking as evidenced by a series of in situ DRIFTS results of propane adsorption. A different reaction mechanism involving the accelerated cleavage of CH bond and removal of carbonates is presented for the catalyst.

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► Sulfate addition enhances the oxidation activity of Pt/CeO2–ZrO2 catalyst.
► More active sites are created at the interface of Ptδ+/SO42−/CeO2–ZrO2.
► The interfacial sites are critical to the initial CH cracking and CC formation.
► The desorption of water and carbonates is feasible on the sulfated catalyst.