Effect of the Co3O4 load on the performance of PdO/Co3O4/ZrO2 open cell foam catalysts for the lean combustion of methane: Kinetic and mass transfer regimes

In this study, kinetic and mass transfer resistances (pore and interphase diffusion) were evaluated by varying the Co3O4 amount in the catalyst (PdO/Co3O4) supported on the zirconia open cell foam (Zir-OCF) of 30 ppi. The catalytic performance was examined toward the methane combustion in lean conditions (0.5 and 1.0 vol.% CH4 inlet concentration, O-2/CH4 molar ratio 8, WHSV 30, 60 and 90 NL h(-1) g(cat)(-1)). Pore and strut geometry of the bare foam were evaluated by SEM images and X-CT data analysis. Solution combustion synthesis was employed to line the Co3O4 spinel on the foam, while the wetness impregnation for the PdO on the spinel. The various resistances were evaluated and compared at different WHSV by varying the Co3O4 amount. Finally, we derived a correlation that describes the mass transfer in OCFs at low Reynolds numbers.