Stabilizing Highly Dispersed Ni Nanoparticles via Ammonium Citrate-Anchoring and SBA-15 Confinement for Dry Reforming of Methane with Enhanced Anti-Coking Performance

A major challenge faced by conventional Ni-based catalysts in dry reforming of methane (DRM) is rapid performance degradation, which is primarily caused by metal sintering and coking under harsh operating conditions. To address this issue, this study reports a facile ammonium citrate (AC)-assisted impregnation strategy for the synthesis of Ni/SBA-15 catalysts. The hydrogen-bonding network formed between AC molecules and silanol groups on the SBA-15 support enables precise anchoring of highly dispersed Ni nanoparticles (average size: 3.65 nm) both within the mesoporous channels and on the external surface of SBA-15. This strong anchoring effect significantly enhances the metal–support interaction via electronic coupling and interfacial stabilization, thereby effectively suppressing the Ni sintering. Additionally, the AC treatment introduces surface basicity to the catalyst by generating carbonate species on the surface, which optimizes CO2 adsorption and activation capabilities. Benefiting from the synergistic effects of these structural advantages, the AC-assisted 6Ni0.5/SBA-15 catalyst exhibits remarkably enhanced DRM catalytic performance compared to the conventionally impregnated 6NiIMP/SBA-15 catalyst. It maintains stable CO2 and CH4 conversion even under harsh reaction conditions. Systematic characterization results further confirm the AC-modified catalyst possesses superior resistance to both metal sintering and coking. Overall, this work establishes a facile yet effective approach for the design of high-performance Ni-based DRM catalysts, which relies on the rational regulation of precursor–support interactions during the synthesis process.