Influence of various spinel materials supported Ni catalysts on thermocatalytic decomposition of methane for the production of COx-free hydrogen

Abstract

The thermocatalytic decomposition of methane is a promising method to produce COx-free hydrogen. The spinel powders with the common formula of AB2O4 and unparalleled features were widely used as a support of heterogeneous catalysts for the diverse catalytic process. In this research, the spinel powders containing the oxides of magnesium, calcium, barium, strontium, iron, and zinc were synthesized based on the solid-state mechanochemical preparation method, and the samples were used as catalyst support for the nickel-based catalysts in the thermal decomposition of methane for the production of COx-free hydrogen. XRD, BET, CO2-TPD, H2-TPR, TPO, and FESEM techniques were carried out to identify the physicochemical characteristics of the fresh and spent samples. The results showed that all samples have a nanocrystalline structure with excellent properties. The results demonstrated that the FeAl2O4-supported nickel catalyst presented the highest stability among the studied catalysts. The decline in the initial CH4 conversion was about 21% at 575 °C during the 300 min time on stream. However, other samples were completely deactivated during the stability test, which was related to the deposition and growth of the carbon nanofiber that covers the available catalyst active sites. The effect of the GHSV value (40000–60,000 ml.h−1.g−1cat), CH4:N2 (10:90–30:70), and reduction temperature (600–800 °C) were also investigated on the catalytic performance and rate of the deposited carbon of the 40 wt% NiO/FeAl2O4.