Development of cobalt-copper nanoparticles as catalysts for higher alcohol synthesis from syngas

The synthesis of higher alcohols from syngas has been studied over different types of Cu-based catalysts. In order to provide control over the catalyst composition at the scale of a few nanometers, we have synthesized two sets of Co-Cu nanoparticles with novel structures by wet chemical methods, namely, (a) cobalt core-copper shell (Co@Cu) and (b) cobalt-copper mixed (synthesized by simultaneous reduction of metal precursors) nanoparticles. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The catalysts were tested for CO hydrogenation at temperatures ranging from 230 degrees C to 300 degrees C, 20 bar and 18,000 scc/(hr.gcat). It was observed that the Co-Cu mixed nanoparticles with higher Cu concentration exhibit a greater selectivity towards ethanol and C2+ oxygenates. The highest ethanol selectivity achieved was 11.4% with corresponding methane selectivity of 17.2% at 270 degrees C and 20 bar. (C) 2009 Elsevier B.V. All rights reserved.