Andvanced catalyst development for tri-reforming of Biogas: toward sustainable and safe hydrogen production

The transition toward a low-carbon energy system requires the development of robust and cost-effective catalytic technologies for the conversion of renewable feedstocks into clean fuels. In this context, biogas represents a strategic resource, enabling the simultaneous valorization of methane and carbon dioxide. Among the available routes, the tri-reforming of methane (TRM), which combines steam reforming, dry reforming, and partial oxidation in a single reactor, offers high process flexibility and tunable syngas composition. However, its industrial application is limited by catalyst deactivation due to sintering, coke formation, and reoxidation. This doctoral research focuses on the rational design of advanced nickel-based catalysts for the efficient and stable tri-reforming of biogas. An integrated approach combining thermodynamic modeling, controlled synthesis, advanced physicochemical characterization, and catalytic testing under realistic conditions was adopted. Aspen Plus simulations were used to identify thermoneutral operating conditions, providing a reliable framework for catalyst assessment. Several synthesis routes were explored, with the Pechini polymerization method proving particularly effective in achieving high nickel dispersion and strong metal–support interactions on ceria–zirconia supports. The influence of promoters was systematically investigated. Lanthanum and magnesium enhanced surface basicity and CO2 activation, while gadolinium and yttrium improved oxygen storage capacity and redox properties. On the active phase, non-noble promoters such as copper and iron significantly improved catalyst stability by promoting oxidant activation and mitigating carbon deposition. A key outcome of this work is the identification of an in situ formed Ni/LaCZO core–shell architecture associated with sub-stoichiometric LaNiOₓ phases, which exhibited excellent coke resistance and long-term stability, achieving performances comparable to noble-metal-based systems at lower cost. Finally, structured catalysts based on Ni-containing layered double oxides demonstrated good scalability and industrial relevance. Overall, this work provides viable solutions for the sustainable conversion of biogas into hydrogen and syngas, supporting the advancement of TRM as a low-carbon catalytic technology.