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 catalyst. Long-term testing at 650 °C showed stable catalytic behavior of the Ni/GDC–Al2O3 catalyst, while operational observations qualitatively suggested the absence of significant carbon deposition, consistent with equilibrium calculations.