Copper Nanoparticles-Based Catalysts
As in a number of other areas where nanomaterials are applied as catalysts for efficient chemical transformations, Cu and Cu alloy- based nanoparticle catalysts have been tested for higher alcohol production from syngas [52,53]. In one example, Gupta and Spivey prepared Cu-ZnO and Mn-Cu-ZnO nanomaterial catalysts by electrodeposition, and tested for the synthesis of higher alcohols via CO hydrogenation. These catalysts were prepared in the form of nanowires and nanotubes using a nanoporous polycarbonate membrane, which served as a template for the electrodeposition
of the precursor metals from an aqueous electrolyte solution. Electrodeposition was carried out using variable amounts of Zn(NO3)2, Cu(NO3)2, Mn(NO3)2 and NH4NO3 at different galvano — static conditions. A fixed bed reactor was used to study the reaction of CO and H2 to produce alcohols at 270°C, 10-20 bar, H2/CO = 2/1, and 10,000-33,000 scc/h gcat. As Gupta and Spivey reported, these Cu nanomaterial catalysts failed to give high ethanol selec — tivities; methane and methanol were the main products. The addition of manganese to the Cu-ZnO catalyst increased the selectivity toward higher alcohols by reducing methane formation; however, maximum ethanol selectivity was only 5.5%, measured as carbon efficiency [53].