Dry reforming reactions of CH4 over CeO2/MgO catalysts at high concentrations of H2S, and behavior of CO2 at the CeO2-MgO interface

• Published in: Journal of catalysis Vol. 407; pp. 29 - 43
• Main Author: Taira, Kenji
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.03.2022
• Subjects: CeO2; DRIFT; Dry reforming; H2S; Isotopic labeling; MgO; TEM; MgO; H2S; Dry reforming; CeO2; TEM; DRIFT; Isotopic labeling
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2022.01.022

[Display omitted] •Stable activity of CeO2/MgO was demonstrated in CH4 reforming with 2000 ppm H2S.•5 mol% CeO2/MgO exhibited comparable activity to that of pure CeO2.•No carbon deposition or phase change was observed after the reaction.•DRIFT and isotopic labeling showed CO2 at CeO2-MgO interface promoted the reaction.•SOx formed at the CeO2-MgO interface supplies oxygen to the CeO2 surface. High concentrations of H2S are contained in unused industrial gases and biomass gasification gases, necessitating catalysts which are robust in the presence of H2S to produce H2 from them. Pure CeO2 is known for its robustness, but rare earth oxide consumption should be reduced to improve sustainability. Herein, a stable dry reforming reaction is demonstrated over CeO2/MgO under reaction conditions of 2000 ppm H2S. A comparable catalytic activity to pure CeO2 was exhibited by 5 mol% CeO2/MgO despite its low loading of CeO2. Further, no carbon deposition or impurity phases were formed in the catalyst after an 8-h reaction. Transmission electron microscopy revealed that MgO stabilized the CeO2 nanoparticles under these reaction conditions. Also, kinetic analyses, infrared spectroscopy, and isotopic labeling studies suggested that the CeO2-MgO interface strongly captures CO2 and supplies it to the CeO2 surface to accelerate the dry reforming reaction.