High-dispersion CeO2-promoted Ca-Ni composites for coupled CO2 capture and methane dry reforming: Improved cycle stability and reforming efficiency

Abstract

Ni–Ca-based dual-functional materials have been widely employed in calcium looping–assisted dry reforming of methane (CaL–DRM) to enable efficient CO₂ capture and in situ conversion. However, their performance and operational lifetime are often severely limited by carbon deposition and Ni particle sintering during cyclic CaL–DRM processes. In this study, a Ni–Ca₁₀Ce dual-functional material with highly dispersed CeO₂ was successfully synthesized via a citrate complexation method. The structural and catalytic properties of the material were systematically investigated. Characterization results revealed that the incorporation of highly dispersed CeO₂ significantly optimized the pore structure and, through interfacial synergy with Ni, greatly enhanced oxygen mobility. CaL–DRM cycle experiments demonstrated that at 650 °C, Ni–Ca₁₀Ce exhibited excellent synergistic catalytic performance, achieving a hydrogen production rate of 0.827 mmol/g·min with good cyclic stability. Optimization of reaction conditions revealed that the material achieved its best catalytic performance at a CH₄ flow rate of 50 mL/min, with hydrogen yield increasing to 1.0 mmol/g·min. Long-term stability tests showed that after 10 CaL–DRM cycles, the CO₂ and CH₄ conversion rates decreased by only 4.6 % and 7.6 %, respectively—markedly superior to CeO₂-free Ni–Ca materials. SEM analysis further confirmed that the highly dispersed CeO₂ on the surface effectively suppressed Ni particle sintering and carbon accumulation, serving as a key factor in ensuring the catalyst’s long-term operational stability. This study provides a novel strategy for material development and performance enhancement in the CaL–DRM system.