Metallurgical preparation of nano-sized Cu from a solid solution of rod-like CuFe2O4 : suitable for application in high performance catalysis

A novel solid solution synthesis method, using a mesoporous template that produces nano-sized copper (~3.6 nm grain size) by the thermal hydrogen reduction (THR) of spinel CuFe2O4 nano-crystals, that have a high surface area ~ 126 m 2 /g, (c.f. commonly cited literature values < 10 m 2 /g) and a rod-like morphology, is described. In situ XRD and temperature program reduction (TPR) results showed that the precipitation of the copper nanoparticles occurred at 210 oC, which is lower than other reported literature values - due to the fine grain size of the spinel CuFe2O4. The precipitated copper nanoparticles were also characterized by, XANES, and FT-EXAFS. Here we have used steam reforming of methanol as a model reaction to demonstrate the capability of the materials formed in which a 100% conversion of methanol by steam reforming was achieved at approximately 240 oC. The proposed synthesis method combines metallurgy and THR while at the same time effectively resolving issues related to the large grain sizes, higher calcinations temperature (above 750oC) and low surface areas (below 10 m 2 /g), that commonly occur in conventional solid state methods. The solid solution synthesis method, using a mesoporous template, can also to be applied to other heterogeneous metal oxide systems.