Integrated CO₂ capture and methane dry reforming over a Ni–Ca dual functional material under SO₂/NO₂-containing flue gas conditions: a mechanistic study

Integrated carbon capture and utilization (ICCU) has emerged as a promising strategy toward carbon neutrality. However, most existing studies rely on simulated flue gas compositions, neglecting the impact of common impurities such as sulfur oxides (SO_x) and nitrogen oxides (NO_x), thereby limiting the practical industrial applicability of ICCU technologies. Herein, we systematically investigate the effects of SO₂ and NO₂ at various concentrations on the adsorption–catalysis performance based on a representative Ni–Ca dual functional material (DFM) in the ICCU–dry reforming of methane (ICCU-DRM) process. Exposure to 100 ppm SO₂ showed a negligible influence on catalytic activity but markedly inhibited carbon deposition. Further increasing the SO₂ concentration to 500 ppm led to complete deactivation of the DFM. NO₂ exhibited a similar concentration-dependent trend to SO₂, albeit with a comparatively lower impact. Mechanistic analysis revealed that both SO₂ and NO₂ promote the formation of a coating layer of calcium-containing compounds on the surface of Ni nanoparticles, accounting for the partial or total deactivation. These findings offer critical insights into the industrial applications of ICCU systems under realistic flue gas conditions.