(Synthesis of barium cerate by EDTA-citrate complexing method and catalytic evaluation under carbon monoxide stream tested in fixed-bed reactor)

Abstract

The barium cerate perovskite was synthesized using a methodology based on the EDTA-citrate complexing method and its catalytic properties were tested in fixed-bed reactor at different stream feeding gas flow rates (50 and 100 mL.min^-1) and temperatures (100 to 550 °C). The intended crystalline phase was obtained with crystallite size of 133 nm, together with a small amount of unwanted BaCO₃ phase (3%). When synthesized by the EDTA-citrate complexing method, the barium cerate presents an irregular spherical shape with clusters of different sizes, and the presence of pores of different size distributed randomly; its specific surface area was 2.61 m².g^-1. At flow rate of 50 mL.min^-1, higher conversion then at 100 mL.min^-1 was observed, becoming more apparent between 300 and 400 °C. Moreover, at 50 mL.min^-1 flow rate total conversion of CO to CO₂ occurred at 400 °C, while the conversion was close to 60% at 100 mL.min^-1. Using the perovskite as catalyst the oxidation process is completed at 400 °C, while in reaction without catalyst the complete conversion is achieved only at 550 °C. Therefore, the BaCeO₃ had strong activity in carbon monoxide oxidation, although its specific area was small.

Keywords:
perovskite; EDTA-citrate complexing method; catalytic properties; specific area; feed flow; carbon monoxide