Performance studies of Pt, Pd and PtPd supported on SBA-15 for wet CO and hydrocarbon oxidation

Climate change is one of the most pressing issues confronting modern society due to the greenhouse gas emissions. Reducing anthropogenic greenhouse gas emissions is critical to preventing further global warming. This work explores the oxidation of methane, propane and ethylene in the presence of carbon monoxide (CO) and water vapors over Pt and Pd mono and bimetallic catalysts supported on SBA-15. Pt and Pd catalysts with uniform distribution are prepared on high surface area SBA-15 support using different precursors and solvents. The performance of catalysts is evaluated as a function of temperature and time. The inhibitory effect of water vapors and co-feeding of carbon monoxide is studied on the light-off temperature and stability of Pt, Pd and bimetallic catalysts. We performed in-depth characterization using XRD, BET, XPS, TEM, CO chemisorption and ICP-OES techniques to correlate the properties of catalysts with oxidation results. In terms of their oxidation activity, Pd exhibited higher activity towards alkanes (methane and propane) at low temperatures, while Pt is more active for ethylene. Carbon monoxide undergoes oxidation at the lowest temperature over both Pt and Pd, followed by the oxidation of all other components in the feed. It is confirmed that PdO remains highly active when reductants are only alkanes. However, the coexistence of M/MOx ionic species (Pt⁰, Pt²⁺, Pd⁰, Pd²⁺) appears be to more active when mixed feed is used. Optimal alloying compositions have the potential to minimize the decrease in conversion activity in the presence of CO and water vapors. This work is expected to advance the rational synthesis and application of multicomponent and multifunctional catalytic materials.