Efficient catalytic decomposition of CO2 to CO and O2 over Pd/ mixed-conducting oxide catalyst in an oxygen-permeable membrane reactor.

Abstract

The thermal decomposition of CO2 to CO and O2 is a potential route for the consumption and utilization of CO2. However, this reaction is limited by both the thermodynamic equilibrium and the kinetic barrier. In this study, we reported an innovative catalytic process to decompose CO2 in an oxygen-permeation membrane reactor packed with a mixed-conducting oxide supported noble metal catalyst, or Pd/SrCo0.4Fe0.5Zr0.1O3-delta (Pd/ SCFZ), which is of high activity in the decomposition of CO2 into CO and O2. Pd/SCFZ catalyst was prepared by incipient wetness impregnation of the SCFZ powders with an aqueous solution of PdCl2, and the CO2 sorption/desorption property was examined by in situ Fourier transform infrared spectroscopy and temperature-programmed desorption-mass spectrometry technologies. It was shown that there appeared a typical of bridged carbonyls (Pd-CO) on the surface of the Pd/SCFZ catalyst formed after CO2 decomposition. Both CO2 and CO could be detected in the species desorbed from Pd/SCFZ catalyst, which implied that the Pd/SCFZ catalyst could effectively activate the CO2 molecule. During the catalytic process, furthermore, the activity of the Pd/SCFZ catalyst can self-regenerate by removing the produced lattice oxygen through the dense oxygen-permeable ceramic membrane. At 900 degrees C, this catalytic process attains 100% of CO formation selectivity at 15.8% of CO2 conversions.