Oxygen vacancies engineering of Fe doped LaCoO3 perovskite catalysts for efficient H2S selective oxidation

Abstract

Fe-doped LaCoO3 perovskite catalysts synthesized via a facile citric acid-assisted sol-gel route have been applied for the H2S selective oxidation. The as-synthesized LaFexCo1−xO3 perovskites exhibit a randomly macroporous structure formed by the accumulation of nanoparticles. Characterization studies reveal that appropriate Fe substitution effectively enhances the formation of oxygen vacancies, and thus improves the lattice oxygen mobility and H2S adsorbability, respectively. The obtained LaFe0.4Co0.6O3 exhibited remarkable catalytic activity, with the H2S conversion and sulfur yield of 100% at 190 °C. A combined approach of in-situ FT-IR and in-situ Raman experiments disclosed that the plausible reaction pathway of H2S selective oxidation over LaFexCo1−xO3 perovskites follows the Mars-van Krevelen mechanism. The density functional theory calculations revealed that Fe-doping improves the formation of oxygen vacancy and enhances the adsorption of H2S. This study offers new insights for the design of highly efficient perovskites for the selective oxidation of H2S.