Preparation of nano-sized Cu from a rod-like CuFe2O4: Suitable for high performance catalytic applications

Abstract

A space-confined synthesis method, using a mesoporous template that produces nano-sized copper (∼3.6nm crystal size) by the thermal hydrogen reduction (THR) of spinel CuFe2O4 nano-crystals, that have a high surface area ∼126m2/g, (c.f. commonly cited literature values <10m2/g) and a rod-like morphology, is described. In situ XRD and temperature program reduction (TPR) results showed that the generation of the copper nanoparticles occurred at 210°C, which is lower than other reported literature values—due to the fine crystal size of the spinel CuFe2O4. The generated copper nanoparticles were also characterized by XANES, and FT-EXAFS. We have used the steam reforming of methanol (SRM) 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°C. The proposed synthesis method combines metallurgy and THR while at the same time effectively resolving issues related to the large crystal sizes, higher calcinations temperature (above 750°C) and low surface areas (below 10m2/g), that commonly occur in conventional solid state methods. The mixed metal oxide synthesis method, using a mesoporous template, can also be applied to other heterogeneous metal oxide systems.