Hydrogen production from COx-Free thermocatalytic decomposition of methane over the mesoporous iron aluminate spinel (FeAl2O4) nanopowder supported nickel catalysts

Abstract

In the present study, the thermocatalytic decomposition of methane (TDM) was performed over the NiO(x)/FeAl2O4 catalysts with various contents of nickel oxide. The FeAl2O4 catalyst support with mesoporous structure and high SBET (80.26 m2 g−1) was synthesized according to the carbonate-based mechanochemical method. The calcined catalysts were characterized by the XRD, BET, H2-TPR, CO2-TPD, TPO, and FESEM analyses. The obtained results demonstrated that the SBET of the synthesized catalysts reduced from 62 to 26 m2 g−1 by increasing the nickel loading from 20 to 60 wt.%, which is ascribed to the blockage of FeAl2O4 support pores. Furthermore, the activity results showed that the catalytic activity improved by increasing the nickel content from 20 to 50 wt.% due to the rise of active site concentration. However, the methane conversion was reached to 40% at 600 °C over the NiO(50)/FeAl2O4 catalyst. The more increment of nickel content decreased the catalytic efficiency due to the decline in active phase dispersion. Moreover, the increment amount of deposited carbon was seen by increasing the weight percentage of NiO. Therefore, the catalyst with 50 wt.% of NiO possessed excellent catalytic potential in the TDM process under the hard operating conditions (GHSV = 50,000 ml.h−1.g−1cat). The influence of GHSV, feed ratio (CH4:N2), calcination temperature, and reduction temperature on the textural properties and catalytic activity of the NiO(50)/FeAl2O4 catalyst were also evaluated in detail.