Enhancing the photothermal catalytic performance and stability of Ni–MOx–Al2O3 (M = Ce, Pr, and Y) for DRM: the role of rare earth elements

Abstract

The integration of photocatalysis and thermal catalysis offers a sustainable route to drive the dry reforming of methane (DRM) at low temperatures, addressing the high energy consumption of traditional thermocatalytic processes. Herein, we systematically explore the effects of doping rare earth elements (Ce, Pr, and Y) on the photothermal catalytic activity and stability of Ni-based catalysts (Ni–MOx–Al₂O₃) for DRM. Results demonstrate that Ce doping significantly enhances charge carrier separation efficiency and reduces interfacial impedance, endowing Ni–Ce–Al with superior photocatalytic activity compared to Ni–Pr–Al and Ni–Y–Al catalysts. After 100 h of continuous reaction at 650 °C, the conversions of CH₄ and CO₂ only decrease from 59.0% and 62.0% to 52.6% and 56.8%, respectively. Mechanistic studies reveal that Ce incorporation increases the density of surface oxygen vacancies, which promotes the activation of CH₄ and CO₂ and enhances coke resistance under light conditions. Kinetic analysis confirms that Ni–Ce–Al possesses the lowest activation energies for CH₄ (40.6 kJ mol⁻¹) and CO₂ (36.7 kJ mol⁻¹) dissociation under illumination. This work provides helpful guidance for the design of high-performance Ni-based photothermal catalysts for DRM through rare earth modification, highlighting the crucial role of Ce in optimizing electronic properties and anti-coking ability.