Influence of catalyst synthesis methods on anti-coking strength of perovskites derived catalysts in biogas dry reforming for syngas production

This study examined biogas dry reforming using perovskite-derived catalysts over the temperature range of 650–850 °C. Citrate-gel combustion and co-precipitation methods were used to prepare perovskites (LaCoO₃ and LaNiO₃). These perovskites were converted into metal-supported catalysts by reduction process. Also, impregnation was applied for the synthesis of 30 wt% Ni/La₂O₃ and 10 wt% Ni/Al₂O₃. X-ray diffraction and high-resolution transmission electron microscopy confirmed that the average particle size of Ni or Co was smaller in the combustion method over co-precipitated method. Citrate-gel combustion method favors La₂O₂CO₃ phase, whereas co-precipitation method prefers La(OH)₃ phase in the support. Although the biogas dry reforming condition used in this study (CH₄/CO₂ = 1.5) is much severe for coke deposition than conventional dry reforming condition (CH₄/CO₂ = 1.0), the catalyst derived from perovskite LaNiO₃ by citrate-gel combustion method showed outstanding performance among examined catalysts. The La₂O₂CO₃ phase self-regenerates and oxidizes carbon from the nickel sites continuously. The high anti-coking strength was attributed to the highly dispersed nickel nanoparticles, La₂O₂CO₃ species, and low acidity confirmed by NH₃-TPD. Therefore, the citrate-gel combustion method is an alternative to conventional methods for biogas dry reforming.