Hydrogen production via methane partial oxidation over SBA-15-coated cordierite monolithic NiO catalysts: Synergistic effects of CeO2 and ZrO2 doping

Abstract

This study investigates the effect of mesoporous silica (SBA-15) combined with nickel and metal oxides on hydrogen production. Metal, metal oxide and SBA-15 solutions were successfully coated on the surface of cordierite monolith using the wash coating method. The characterization results confirmed the structural and chemical properties of the synthesized catalysts. SEM-EDS analysis demonstrated the uniform distribution of active components within the monolithic framework, ensuring effective metal dispersion. XPS spectra identified the binding states of Ni, Ce, and Zr, elucidating the active metal species responsible for catalytic activity. BET analysis revealed that alumina-supported catalysts exhibited a pore size range of 9-13 nm along with an enhanced surface area. XRD analysis confirmed the high crystallinity of the cordierite structure and the presence of NiO, CeO2, and ZrO2 phases. TPR analysis provided insights into metal-support interactions, highlighting the reducibility of NiO species and the temperature range at which reduction occurs. The catalytic performance of the synthesized monolithic catalysts was assessed in the partial oxidation of methane at reaction temperatures of 750, 800, and 850 degrees C under GHSV conditions of 10,000 and 20,000 h-1. The results indicated that decreasing the GHSV to 10,000 h-1 significantly improved methane conversion due to prolonged gas-catalyst contact time, thereby enhancing reaction efficiency. Among the catalysts, SBA-15/ZrO2/Ni exhibited the highest CH4 conversion and stability, maintaining a conversion of 95.6% at 800 degrees C after 10 h, while demonstrating minimal coke accumulation (0.22 mg C/gsupported catalyst). Although alumina-containing catalysts initially achieved higher CH4 conversion and H2 selectivity, they exhibited greater susceptibility to coke deposition over time, which affected their long-term stability.