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

A space-confined synthesis method, using a mesoporous template that produces nano-sized copper (∼3.6 nm crystal size) by the thermal hydrogen reduction (THR) of spinel CuFe2O4 nano-crystals, that have a high surface area ∼126 m2/g, (c.f. commonly cited literature values <10 m2/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 10 m2/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.

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• A mesoporous template was used to produce nano-sized copper, by the thermal hydrogen reduction of spinel CuFe2O4nano-crystals.
• The resulting copper had an estimated size of 3.6 nm and a surface area of 115 m2/g and the required reduction temperature is less than 210 °C.
• Steam reforming of methanol was used as an example to show the capability of the catalyst, whereby a 100% conversionwas achieved at around 240 °C.
• This proposed synthesis method that produces finely dispersed nanoparticles can be extended to other mixed metal oxide systems and various applications.