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

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 2p_3/2 and Fe 2p_3/2 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.