Dynamical Properties of a Ru/MgAl₂O₄ Catalyst during Reduction and Dry Methane Reforming

Abstract

Combined in situ small-and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a new laboratory setup to investigate the dynamical properties of a ruthenium/spinel (Ru/MgAl 2 O 4 ) catalyst, w(Ru) = 4 wt %, during the reduction and subsequent dry methane reforming. The Ru particles in the fresh catalyst sample were found to be partially oxidized. High-resolution transmission electron microscopy (HRTEM) indicated a coexistence of pure Ru and RuO 2 nanoparticles. Reduction in hydrogen occurred at a temperature between 373 and 393 K. The mean particle diameter as refined from SAXS of the size regime attributed to scattering from Ru/RuO 2 -particles decreases slightly by about 0.2 nm during the reduction. Dry methane reforming experiments were performed in a temperature interval from 723 to 1023 K by applying a gas mixture of carbon dioxide and methane in molar ratio of 3:1. The catalyst did not show any deactivation during the experiment of overall 32 h, indicated by stable turnover frequencies for methane. The mean Ru-particle diameter remained constant during the dry methane reforming experiments, revealing a high sintering stability of the Ru/MgAl 2 O 4 catalyst.

Thermodynamic analysis of dry reforming of CH4 with CO2 at high pressures

“…7(c). For the cases with excess CO 2 , the H 2 /CO ratio can be lower than 1 because of the increase in CO and decrease in H 2 (De Arauj et al, 2008;Kehres et al, 2012). Fig.…”

Effects of Platinum and Palladium Metals on Ni/Mg1-xZrxO Catalysts in the CO2 Reforming of Methane

“…The H2/CO ratio of Pd,Pd,Ni/Mg0.85Zr 4+ 0.15O was 1.28 when the temperature was 900 °C. This result indicates that the RWGS reaction (Equation 8) causes slight effect [7] because the concentration of hydrogen will remain high while the concentration of carbon monoxide is low and therefore the H2/CO ratio remains high. Figure 9 presents the result obtained from the test involving temperature.…”

“…Furthermore, these metals resist carbon from being formed more effectively compared with other transition metals [7], since Ni catalysts are more favorable with noble metals, such as Rh, Pt, Pd, or Ru. They increase the reaction of the catalysts, and they are more stable in their reaction against coke deposition when compared with that of the other non-favorable Ni catalysts [8].…”

Dry Reforming of Methane: Catalytic Performance and Stability of Ir Catalysts Supported on γ-Al2O3, Zr0.92Y0.08O2−δ (YSZ) or Ce0.9Gd0.1O2−δ (GDC) Supports

“…DRM has been investigated over a variety of metal catalysts, including Ni [5,[16][17][18][19][20][21][22][23][24][25], Pt [2,18,26,27], Rh [8,17,[26][27][28][29][30], Ru [26,27,31,32], Pd [17,26,27,33], Co [26,28] and Ir [26,27,34,35], supported on oxide (e.g., Al 2 O 3 , La 2 O 3 , CeO 2 , SiO 2 , TiO 2 ,) or mixed oxide supports (e.g., La 2 O 3 -SiO 2 , ZrO 2 -SiO 2 , PrO 2 -Al 2 O 3 ). Generally, Ni based catalysts seem to present high activity and selectivity towards synthesis gas and in combination with their low cost are often preferable.…”