Preparation of highly dispersed catalytic Cu from rod-like CuO–CeO2 mixed metal oxides: suitable for applications in high performance methanol steam reforming

Abstract

A space-confined synthesis method, using a mesoporous template to produce nano-sized copper particles (∼2 nm diameter) by the thermal hydrogen reduction (THR) of high surface area (∼105 m² g⁻¹) rod-like CuO–CeO₂ calcined at 700 °C, is described. X-Ray diffraction (XRD) and temperature program reduction (TPR) results showed the CeO₂ to be doped with Cu, thereby creating more oxygen vacancies. The excess Cu has a high degree of dispersion around 60%. Here we have used the steam reforming of methanol as a model reaction to demonstrate the capability of the materials formed and have used this as a basis of comparison with the impregnation method (carried out at 400 °C) using the same weight loading of Cu. Turnover frequency (TOF) analysis showed the rod-like CuO–CeO₂ mixed oxides to have a 3 fold better catalytic performance compared to analogous materials made by the impregnation method. Additionally, we show that the incorporation of Cu atom into the surface, i.e. non-particulate, structure of CeO₂ provides additional activity sites that are useful in augmenting catalytic performance.