Effect of Gadolinium-Doped Ceria (GDC) Promoter on the Catalytic Activity of Ni/Al₂O₃ in Methane Dry Reforming

Dry reforming of methane (DRM) is an attractive route for H2 production and simultaneous CO₂ utilization, but its practical implementation is limited by catalyst deactivation. This study experimentally investigates the catalytic performance of Ni/Al₂O₃ and Gd-doped ceria–promoted Ni/GDC–Al₂O₃ catalysts for DRM in a fixed-bed quartz reactor over 400–800 °C at gas residence times of 0.1 s and 0.4 s. Increasing temperature and residence time enhanced CH₄ and CO₂ conversion as well as H₂ and CO yields for both catalysts. The GDC-promoted catalyst exhibited markedly improved activity, achieving conversions and product yields at 0.1 s comparable to those of Ni/Al₂O₃ at 0.4 s and reaching complete CH₄ conversion at about 650 °C, approximately 100 °C lower than the Ni/Al₂O₃. Long-term testing demonstrated high durability of Ni/GDC–Al₂O₃ at 650 °C with no detectable carbon deposition, consistent with thermodynamic equilibrium analysis.