Toward enhanced conversion of model biogas mixtures: parametric tuning and mechanistic study for ceria–zirconia supported nickel–cobalt catalyst

Abstract

This work underlines the parametric tuning and mechanistic study for ceria–zirconia (CeZr) supported bimetallic NiCo in methane dry reforming (MDR) with carbon dioxide. CeZr mixed oxides were calcined at three separate temperatures, i.e. 300, 350 and 400 °C. 1.5, 2.0, 2.5 and 3.0 wt.% NiCo were deposited onto CeZr support to assess their activity in MDR. Their physicochemical properties were characterized via XRD, FESEM, N₂ sorption, He pycnometry, TG-DSC, TPR and TPO. Results show that lower calcination temperature renders larger surface area in CeZr for more effective NiCo anchoring and particle dispersion. The optimum calcination temperature for CeZr was 350 °C, in which agglomeration-free morphology was identified. 2.5 wt.% emerged as the optimized loading parameter for NiCo deposition. This particular catalyst supported on CeZr calcined at 350 °C displays the best performance for 20 h of MDR in terms of syngas yield (CO = 61%, CO production rate = 11.1 mol (g_cat h)⁻¹; H₂ = 38%, H₂ production rate = 7.0 mol (g_cat h)⁻¹) and low carbon deposition (0.1 wt.%). Kinetic and mechanistic study infers that calcination temperature of CeZr support and adequate loading of NiCo are pivotal toward enhancing MDR activity.