Facilely Synthesized CeNi1-xCoxO3 Perovskite Catalyst for Combined Steam and CO2 Reforming of Methane

Herein, a series of CeNi1-xCoxO3 (x = 0.1, 0.3, 0.5, and 0.7) was prepared by a co-precipitation method for combined steam and CO2 reforming of methane (CSCRM) reaction. The influence of incorporating Ni with Co species in the perovskite structure was elucidated by both the catalytic performance and physicochemical properties of as-prepared materials. Several modern techniques were utilized to study the catalysts' properties, including XRD, EDS, SEM, HR-TEM, Nitrogen adsorption-desorption, H2-TPR, CO2-TPD, and Raman spectroscopy. As Co modification content increased, respective to x value in CeNi1-xCoxO3 change from 0.1 to 0.5, calcined catalysts' crystallite size of separated M2Ox oxides gradually increased from 16.2 to 20.3 nm. Investigating the CO2-TPD and H2-TPR profiles showed that CO2 adsorption ability of catalysts increased while reducibility decreased when x value increased from 0.1 to 0.5. Despite clearly change of physicochemical properties, the Co content in range of x = 0.1-0.5 did not have significant influence on the catalytic activity in CSCRM reaction. The properties of catalyst with higher Co content (x = 0.7) changed differently compared to catalysts with x = 0.1-0.5, which seemed positive (smaller crystallite sizes of calcined perovskite and reduced metallic phases of 12.9 nm and 12.8 nm, respectively; slightly larger specific surface area of 13.0 m2/g, higher hydrogen consumption in TPR analysis), but the catalytic activity of this catalyst slightly lower than other surveyed catalysts at a low temperature of 550 degrees C. Despite that, all studied catalysts showed quite similar catalytic performance at high temperature range, which was considered as favorable operation condition for the reaction. The study also revealed an excellent coke tolerance ability of perovskite-derived catalysts in the CSCRM. The as-prepared CeNi0.5Co0.5O3 catalyst showed a comparable activity compared to other published results on other catalysts, with CH4 and CO2 conversions of 94.6% and 93.2%, respectively. The comparison with other studies also revealed a high CH4 conversion rate of 6381 mLCH4.g-1.h-1 and an excellent CO2 conversion rate of 3269 mLCO2.g-1.h-1 on CeNi0.5Co0.5O3 in a high space velocity of 3 x 105 mL.g-1.h-1.