Effect of polymerization/complexation agents molar ratio on structure and catalytic activity of La0.7Ba0.3Co0.3Ni0.7O3 nanocatalyst in low-temperature CO oxidation

Abstract

Nano-sized perovskite-type oxides of La0.7Ba0.3CoxNi1-xO3 (LBCN) catalysts with x = 0.3, 0.5 and 0.7 were synthesized by polymerized complex method based on the Pechini-type reaction route wherein ethylene glycol and citric acid were used as polymerization/complexation agents. The effects of different ethylene glycol/citric acid molar ratio in the sol–gel process on the structure and catalytic activity of the synthesized La0.7Ba0.3Co0.3Ni0.7O3, which displayed superior catalytic performance toward CO oxidation, were examined. The structure, component band identification, morphology, reducibility, and specific surface area of the prepared LBCNs were investigated with X-ray diffraction, FT-IR, SEM, H2-TPR, and BET, respectively. According to H2-TPR results, the shift of reduction peaks of the LBCN nanocatalysts to the lower temperatures indicated that the reduction of Co3+ to Co2+ can be carried out at the lower temperatures, resulting in the improvement of the redox capacity of LBCNs. The results confirmed superiority of the prepared LBCNs over LaCoO3 especially for EG/CA = 5 for the CO oxidation, resulting in achievement of 90% CO oxidation at 180 °C.