Sol-gel synthesis of Pt-Co-CeOx codierite catalyst for biogas reforming to methanol compatible syngas

Converting biogas into methanol-compatible syngas (H2/CO ≈ 2) presents a viable pathway towards renewable methanol production via single-step synthesis. This study introduces a novel monolithic PtCoCe/cordierite catalyst featuring a Pt-Co alloy and oxygen vacancy-rich CeO2 dispersed on a commercial cordierite support. Comparative analysis demonstrated that sol-gel synthesis yields superior catalytic performance compared to conventional impregnation and co-precipitation methods. The resulting catalyst exhibits high activity, attributed partly to the Pt-Co alloy facilitating CO2 decomposition, and exceptional stability. This stability is achieved through effective mitigation of carbon deposition, facilitated by Co-CoOx and Ce3+-Ce4+ redox cycles. Systematic comparison revealed distinct deactivation pathways: catalysts prepared by impregnation primarily deactivated due to Pt-Co sintering during the reaction, as confirmed by TEM and SEM, whereas those from co-precipitation suffered mainly from carbon deposition, evidenced by Raman and TG analyses. Under optimized reforming conditions (800 °C, 10,600 mL cm−3 h−1 GHSV, CH4:CO2:N2:H2O = 3:2:1:2), the sol-gel catalyst delivered 97 % CH4 conversion, 56 % CO2 conversion, and the target H2/CO ratio near 2, sustaining this performance for over 100 h. Furthermore, its long-term stability and potential for commercial application were validated in a 720-h pilot-scale test conducted under realistic biogas conditions (820 °C, atmospheric pressure).