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

초록

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.

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