Understanding the stability of Co-supported catalysts during ethanol reforming as addressed by in situ temperature and spatial resolved XAFS analysis

Co catalysts, based on alumina supports modified with La2O3 and CeO2, have been explored in the steam reforming of ethanol (SRE). The addition of oxygen in the reactants, process called oxy-reforming of ethanol (ORE), and the effect of adding Pt as a promoter were also addressed. One of the main challenges of this system is to hinder carbon deposition that leads to catalyst deactivation. In this work, the stability against carbon deposition was correlated to the control of the Co2+/Co0 ratio, which was addressed by in situ temperature-resolved X-ray absorption near edge spectroscopy (XANES). Temperature- and spatial resolved XANES indicated that the nature of supports, the presence/absence of Pt promoter and the composition of oxidants (water and oxygen) in the feed stream determine the degree of reduction of Co under reaction conditions. The control of the Co2+/Co0 ratio can equilibrate the steps of ethanol activation and carbon oxidation, resulting in stable catalysts.

Temperature- and spatial resolved XANES indicated that the nature of supports and the composition of reactants determine the Co2+/Co0 ratio in reforming of ethanol, which control the activity and deposition of carbon.Figure optionsDownload high-quality image (147 K)Download as PowerPoint slideHighlights
► Effects of supports on stability of Pt–Co catalysts for ethanol reforming are explored.
► The nature of supports and the presence of Pt determine the degree of reduction of Co.
► The Co2+/Co0 ratio controls the activity and oxidation of the deposited carbon.
► Suppression of carbon deposition is found by changing O2/H2O ratio in the feed.