Sintering- and coking-resistant Ni/HTASAO5 catalysts for high temperature dry reforming of methane

Abstract

Dry reforming of methane (DRM) provides a promising strategy for combating global warming by concurrently converting two greenhouse gases, CH₄ and CO₂, to value-added syngas. To advance its industrial applications, catalysts with resistance to sintering and coking at high temperatures are highly demanded. In the present work, xNi/HTASAO5 catalysts (HTASAO5 is a commercial composite support consisting of 70 wt% aluminum oxide and 30 wt% cerium zirconium solid solution, and x denotes the Ni content) were prepared and tested for DRM at high temperatures (600–1200 °C). Benefiting from the highly dispersed Ni nanoparticles, the strong metal–support interaction, and the abundant surface active oxygen species and oxygen vacancies, the 5.7Ni/HTASAO5 catalyst achieved nearly complete conversion of CH₄ and CO₂ at 950 °C (conversion >99%) without diluent gases, with a H₂/CO ratio approaching 1.0. Even when operating at 1000 °C for 10 hours, the catalyst could maintain stable conversion of CH₄ and CO₂, and the amount of carbon deposited was negligible. It was found that Ni sintering was suppressed by strong Ni–HTASAO5 interaction while coking was avoided by high temperature and catalytic effects that balance the rates of carbon deposition and carbon elimination. This study provides novel perspectives on the industrialization of high-temperature DRM reactions and enhances understanding of the influence of DRM temperature on carbon deposition.