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Author
Gabandé Zapater, Mariona
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Abstract
The Dry Reforming of Methane (DRM) process is gaining much attention these days because of its potential use toward reducing the emissions of atmospheric greenhouse gases (GHG) such as CO2 and CH4. One of the key research areas in this application is enhancing the activity and stability of the heterogeneous catalysts used in the reforming reactions. In this context, the activity of the catalyst depends on its particle size, dispersion on support, physicochemical properties of the substrate, synthesis method, etc., whereas the deactivation of the catalyst is typically caused by the deposition of carbon byproduct and by the sintering of the metal precursor.
In the present study, ceria-rich CeO2-TiO2-CuxO nanocomposites are developed for potential use as catalysts support for the DRM process. The materials consisting of fixed cerium, titanium, and copper loadings (7:2:1) are prepared by a sol-gel assisted hydrothermal synthesis method, using a one-pot precursor mixture, and post- air calcination. A statistical design of experiments (DOE) with central points and a total of eleven experiments is used in order to optimize and determine the effects and interactions of three synthesis variables namely the (i) mol ratio of the structure-directing additive to acetic acid (FA/AA, 0-0.06), (ii) duration of the hydrothermal treatment (12-36h) and (iii) calcination temperature (300-500ºC). Prior to that, two preliminary studies have been carried out to determine the influence of the type of directing additive added to control the growth conditions and the temperature ramp conditions to use for the calcination step.
The prepared materials have been examined via electron microscopy (SEM/EDX), nitrogen porosimetry, X-ray and Raman spectroscopy to evaluate the morphology, texture, surface composition and crystal structure properties of the mixed metal oxides, respectively. The response surface methodology has been utilized to screen how the synthesis variables affect three studied responses (i.e. BET surface area, pore size and crystallite size).
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