Mg and Cu incorporated CoFe2O4 catalyst: characterization and methane cracking performance for hydrogen and nano-carbon production

Abstract

The Cobalt ferrite (CoFe2O4) and cobalt ferrite incorporated with Cu (Cu–CoFe2O4) and Mg (Mg–CoFe2O4) have been synthesized by wet chemical route. In fixed-bed reactor, the CoFe2O4, Cu–CoFe2O4 and Mg–CoFe2O4 were used as catalysts for direct cracking of methane at temperature of 800 °C and 20 mL/min of feed gas flow rate for hydrogen and nano-carbon production. Different characterizations techniques namely XRD, FESEM, XPS, Raman spectroscopy, TGA, BET for fresh and spent catalysts have been executed. The X-ray powder diffraction and Raman spectra confirmed that the fresh catalysts possess a cubic spinel crystal structure. The FESEM images for spent catalysts displayed that filamentous carbons were not formed over catalysts surfaces except a few amount was observed over the spent CoFe2O4 catalyst. XPS results confirmed the purity of the synthesized catalysts and qualitatively evaluate the cation distribution between the tetrahedral and octahedral sites from Co 2p3/2 and Fe 2p3/2 spectra. BET surface area revealed no significant effects in surface area and pore size of CoFe2O4 catalyst by incorporation of Mg and Cu metals. Activity studies showed that incorporation Mg metal on CoFe2O4 improved methane conversion up to 40.03% and hydrogen formation rate of 79.90 mol H2 g−1 min−1 as compared to 31.61% and 66 mol H2 g−1 min−1 for CoFe2O4 catalyst. Whilst, Cu metal incorporation in CoFe2O4 catalyst led to decline the catalyst performance. Structure activity relationship was described in details.