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

Nano-sized perovskite-type oxides of La 0.7 Ba 0.3 Co x Ni 1-x O 3 (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 La 0.7 Ba 0.3 Co 0.3 Ni 0.7 O 3 , 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, H 2 -TPR, and BET, respectively. According to H 2 -TPR results, the shift of reduction peaks of the LBCN nanocatalysts to the lower temperatures indicated that the reduction of Co 3+ to Co 2+ 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 LaCoO 3 especially for EG/CA = 5 for the CO oxidation, resulting in achievement of 90% CO oxidation at 180 °C. Graphical Abstract