Modulating oxidation state of Ni/CeO2 catalyst for steam methane reforming: a theoretical prediction with experimental verification

Abstract

Steam methane reforming (SMR) accounts for 76% of the dedicated hydrogen worldwide, and will remain the process of choice for large-scale hydrogen production for a long time. Durable and efficient catalysts are always desirable for this high-temperature-preferred process. Here, we report the design of a partially oxidized Ni/CeO₂ catalyst with enhanced activity and stability for SMR. Density functional theory calculations were performed to identify the influence of Ni oxidation state on the binding energy of the Ni cluster and the energy barrier of the rate-limiting step. The best catalyst predicted was subsequently synthesized and characterized, which showed superior performance, as expected. During the 1500 min performance test at 700 °C, stable SMR operations were well maintained on NiO/CeO₂-364 °C with an H₂ production rate of 5.0 mmol min⁻¹ and an H₂/CO ratio of 4.3.