Spinel CuFe₂O₄: A precursor for copper catalyst with high thermal stability and activity

Spinel CuFe₂O₄ has been studied as a precursor for copper catalyst. The spinel CuFe₂O₄ was effectively formed on the SiO₂ by calcination in air at 800 °C with the atomic ratio of Fe/Cu = 2. The spinel CuFe₂O₄ on the SiO ₂ was reduced to fine dispersion of Cu and Fe₃O ₄ particles by the H₂ reduction at 240 °C. After H₂ reduction at 600 °C, sintering of Cu particles over the CuFe₂O₄/SiO₂ (Fe/Cu = 2) was inhibited significantly, while fatal sintering of Cu particles over the Cu/SiO₂ (Fe/Cu = 0) occurred. The CuFe₂O₄/SiO₂ catalyst exhibited much higher activity and thermal stability for steam reforming of methanol (SRM), compared with the Cu/SiO₂ catalyst. The spinel CuFe₂O₄ on the SiO₂ can be regenerated after an intentional sintering treatment by calcination in air at 800 °C where the activity is also restored completely. Based on these findings, we propose that spinel CuFe₂O₄ is an effective precursor for a high performance copper catalyst in which the immiscible interaction between Cu and Fe (or Fe oxide) plays an important role in the stabilization of Cu particles.