Achieving stable syngas production during the photothermal synergistic dry reforming of methane over layered double hydroxide-based catalysts with anti-coking performance

Abstract

Dry reforming of methane (DRM) offers a promising route to convert CH₄ and CO₂ into syngas, addressing both greenhouse gas mitigation and carbon resource utilization. However, its practical application is hindered by high energy consumption and severe catalyst deactivation due to coking. Leveraging the structural tunability of layered double hydroxides (LDH), we synthesized three LDH-derived spinel-supported Ni-based catalysts (Ni/XAl₂O₄, X = Mg, Co, and Cu) and evaluated them in photothermal synergistic catalytic DRM (PTSC-DRM). Substituting Cu with Mg in the support markedly increased the specific surface area from 44.81 to 181.29 m² g⁻¹, significantly enhanced CO₂ adsorption capacity, and strengthened the metal–support interactions. At 600 °C and under 2.91 W cm⁻² illumination, Ni/MgAl₂O₄ achieved CH₄ and CO₂ conversions of 38.49% and 42.13%, respectively, and maintained stable performance over 45.5 h of continuous operation. The coking rate was drastically reduced from 5.00 mgC g_cat⁻¹ h⁻¹ (for Ni/CoAl₂O₄) to 0.98 mgC g_cat⁻¹ h⁻¹, with no reactor clogging observed. Mechanistically, light irradiation continuously promotes CO₂ activation through photogenerated electron–hole pairs, synergistically enhancing coking resistance alongside the thermal catalytic pathway. This work capitalizes on the structural versatility of LDH materials and provides a new strategy for designing low-cost, high-stability, and coke-resistant catalysts for PTSC-DRM.