Overcoming the PdO-to-Pd transition during methane partial oxidation: Effect of Pt addition

Partial oxidation of methane (POX) is an efficient route for hydrogen production. Pd-based catalysts have higher methane oxidation conversion and suffer from deactivation due to PdO-to-Pd transition and coke deposition. In this study, the effect of Pt loading on the performance of Pd-based catalysts under POX conditions is studied. The 2 wt% Pd, 1 wt% Pd-1wt% Pt, and 2 wt% Pd-1wt% Pt catalysts supported on γ-Al 2 O 3 are synthesized and characterized. The POX performance is studied between 625 and 725°C, a CH 4 :O 2 ratio of 2, and a GHSV of 36,800 mL/(g.hr). The 2 wt% Pd catalyst showed PdO-to-Pd transition around 675°C with a coke deposition of 43.5%. The Pd-Pt alloy formation was observed in the bimetallic catalysts, which didn't show a PdO-to-Pd transition. The 2 wt%Pd-1wt%Pt catalyst showed 79.8% methane conversion, 94.5% hydrogen selectivity, and 5.4% coke. This enhanced performance is attributed to improved Pd-Pt interactions, oxygen vacancy concentration, and stable PdO-to-Pd redox cycling.