Effect of low loading of yttrium on Ni-based layered double hydroxides in CO2 reforming of CH4

Abstract

Ni/Al/Mg layered double hydroxides (LDHs) modified with low loading of yttrium (0.2 and 0.4 wt%) were used in dry reforming of methane at 700 °C. Physicochemical characterization, such as: X-ray fluorescence, N2 sorption, X-ray diffraction, temperature programmed reduction in H2, temperature programmed desorption of CO2, H2 chemisorption, thermogravimetry analysis coupled by mass spectrometry and Raman spectroscopy, showed that the introduction of low loadings of yttrium lead to a smaller Ni° crystallite size, a decrease in reducibility of the nickel, and a decreased number of basic sites in the modified Ni/LDHs catalysts. The doping with 0.4 wt% of Y improves catalytic activity resulting in higher CH4 and CO2 conversions at 700 °C, i.e., ca. 84% and ca. 87%, respectively with no clear deactivation observed after 5 h run. The increase in CO2 conversion and a decrease of H2/CO ratio indicates that side reactions occurs during DRM.