Synergistic plasma and platinum catalysts interactions in CO2 reforming of propane at room temperature: The role of supports

• Introduction of an effective in-situ plasma reduction approach for catalysts. • Effective Pt particle size control through plasma reduction. • More efficiency of the plasma-reduced catalyst compared to the thermal-reduced one. • Pt/Al 2 O 3 with smallest Pt particle size, highest plasma properties. • Performance influenced by the synergy of plasma properties, Pt particle size, and basic sites. This study investigates the synergistic impact of plasma and catalyst in a hybrid non-thermal plasma system integrated with 1 wt% Pt catalysts supported on diverse catalyst supports (γ-Al 2 O 3 , SBA-15, HZSM-5, CeO 2 , TiO 2 , and multi-wall carbon nanotube (CNT)) at ambient conditions in dry reforming of propane (DRP). To optimize the reaction, the impact of in-situ plasma reduction time was investigated over the Pt/Al 2 O 3 catalyst at varying durations before the DRP reaction. The most favorable catalytic performance was observed at a reduction time of 60 min due to having the highest surface area (284 m 2 /g), which might result in smaller Pt particle size, and the effective reduction of oxidation states to Pt 0 . A comparison of reduction sources also revealed that the plasma-reduced catalyst outperformed the other, which was attributed to the agglomeration of Pt active sites during the thermal reduction process. The chemo-physical properties of different catalysts directly affected the plasma characteristics and catalytic performance. Pt/Al 2 O 3 exhibited the highest performance, attributed to having the smallest mean Pt particle size (0.94 nm) and highest discharge power (13.97 W), effective capacitance (1.41 nF), and charge transfer (0.34 μC) during DRP reaction, leading to a 13 % and 15 % increase in CO 2 and C 3 H 8 conversions, respectively, compared to plasma-only mode. The catalytic performance showed that the synergy of catalysts with higher basic sites and plasma characteristics, along with smaller Pt particle size, resulted in high reactant conversion and syngas selectivity. Binary HRTEM images also indicated the presence of more soft carbon (coke) in the pore channels of the spent Pt/HZSM-5 catalyst than in spent Pt/Al 2 O 3 .