Model CO2 gasification reactions on uncatalyzed and potassium catalyzed glassy carbon surfaces

Our results show that while the energetics of the CO formation step to produce CO from lattice carbon control the energetics of gasification by CO2, the dissociative adsorption step is responsible for the increase in reaction site density and increased gasification rate

S KELEMEN

2004

Scholarcy highlights

  • The individual steps in the uncatalyzed and potassium catalyzed CO2 gasification reaction were studied on glassy carbon surfaces using Temperature-programmed reaction spectroscopy with labeled isotopes, Auger electron spectroscopy, and steady-state reaction kinetics
  • Subsequent CO2 adsorption and dissociation activity were severely limited on uncatalyzed surfaces
  • Potassium catalyzed glassy carbon surfaces were active for CO2 adsorption and dissociation
  • Our results show that while the energetics of the CO formation step to produce CO from lattice carbon control the energetics of gasification by CO2, the dissociative adsorption step is responsible for the increase in reaction site density and increased gasification rate
  • Alkali metals have shown high catalytic activity, reducing the gasification temperature to as low as 150-200 K.Early scholars reckoned that alkali metals could only improve the gasification rate but could not reduce the activation energy.later scholars suggested that this model could not describe the anaphase catalytic effect on the reaction rate and proposed new models for alkali-metal catalysis
  • High CO2 conversion was observed in the presence of helium and it was reduced by less than 5% in the presence of oxygen
  • In the current case, when both CO2 and O2 were present, the former mechanism better explains the present results, since 13CO was not observed in the blank test, but it was clearly formed in the Reverse Boudouard reaction on spent catalysts.The catalytic effect of potassium on glassy carbon surfaces was ascribed to potassium–oxygen–coke compound and it is a remarkable result to find that when potassium was introduced on alumina the same effect was observed.peroxocarbonate species over metal complexes were evidenced by spectroscopic studies
  • The combined use of a wire-mesh reactor and an FT-Raman/IR spectrometer has provided significant insights into the rapid changes in the chemical structure of nascent char during fast pyrolysis

Need more features? Save interactive summary cards to your Scholarcy Library.