Catalytic performance enhancement by alloying Pd with Pt on ordered mesoporous manganese oxide for methane combustion

Article abstract of DOI:10.1016/S1872-2067(16)62567-6

Ordered mesoporous Mn₂O₃(meso-Mn₂O₃) and meso-Mn₂O₃-supported Pd, Pt, and Pd-Pt alloy x(Pd_yPt)/meso-Mn₂O₃; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT-6-templated and poly(vinyl alcohol)-protected reduction methods, respectively. The meso-Mn₂O₃had a high surface area, i.e., 106 m²/g, and a cubic crystal structure. Noble-metal nanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso-Mn₂O₃surfaces. Alloying Pd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd_5.1Pt)/meso-Mn₂O₃gave the best performance; T_10%, T_50%, and T_90%(the temperatures required for achieving methane conversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of 20000 mL/(g·h). The effects of SO₂, CO₂, H₂O, and NO on methane combustion over 1.41(Pd_5.1Pt)/meso-Mn₂O₃were also examined. We conclude that the good catalytic performance of 1.41(Pd_5.1Pt)/meso-Mn₂O₃is associated with its high-quality porous structure, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interactions between Pd-Pt alloy NPs and the meso-Mn₂O₃support.