Isothermal CO2 capture and in-situ conversion in dry reforming of methane using a catalytic sorbent of CaO-Ni/CeO2 prepared via sol–gel method

Sorbent looping dry reforming of methane (SLDRM) represents a promising approach for CO 2 emission reduction and resource utilization, with its advancement hinging on the development of dual functional materials (DFMs) capable of simultaneous CO 2 capture and catalytic methane conversion. In this study, CaO-Ni based DFMs supported on various materials were synthesized via sol–gel method and characterized using SEM, XRD and TGA. Isothermal SLDRM experiments were performed in a fixed bed to evaluate the performance of these materials. Initial screening of support materials revealed that CH 4 conversion activity followed the order: CeO 2 >Al 2 O 3 >La 2 O 3 >MgO ≈ Y 2 O 3 , with CeO 2 emerging as the optimal support due to its superior performance. The synergistic effect of the Ni catalyst and CH 4 atmosphere significantly enhanced low-temperature decarbonization of the sorbent, mitigating sintering and enhancing cyclic CO 2 capture capacity. In-situ CO 2 conversion during CH 4 reforming disrupted the decarbonization reaction equilibrium, enabling efficient isothermal CO 2 capture and decarbonation. Ni decoration significantly enhanced CH 4 conversion, increasing from nearly 0% without Ni to 87% at 10% Ni loading, while higher loadings provided only marginal improvements. Although an increase in reaction temperature enhanced CH 4 conversion, it also increased CO 2 partial pressure, promoting the reverse water gas shift reaction and resulting in a H 2 /CO ratio below 1 when the temperature exceeded 650°C. Stability tests over 10 consecutive SLDRM cycles demonstrated good stability of CaO-10Ni/CeO 2 , maintaining a CH 4 conversion efficiency of 87% and a stable H 2 /CO ratio of approximately 1 at 650°C. Carbon deposition during the CH 4 step was effectively removed during carbonation, as confirmed by Raman spectroscopy, while SEM and XRD analyses revealed preserved surface morphology and phase composition. These findings highlight the excellent reactivity and stability of CaO-10Ni/CeO 2 , positioning it as a highly promising candidate for advancing CO 2 emission reduction and resource utilization strategies.