Copper-Based Catalysts for Selective Hydrogenation of Acetylene Derived from Cu(OH)₂

Replacing precious metals with cheap metals in catalysts is a topic of interest in both industry and academia but challenging. Here, a selective hydrogenation catalyst was prepared by thermal treatment of Cu(OH)₂ nanowires with acetylene-containing gas at 120 °C followed by hydrogen reduction at 150 °C. The characterization by means of transmission electron microscopy observation, X-ray diffraction, and X-ray photoelectron spectroscopy revealed that two crystallites were present in the resultant catalyst. One of the crystal phases was metal Cu, whereas the other crystal phase was ascribed to an interstitial copper carbide (Cu C) phase. The reduction of freshly prepared copper (II) acetylide (CuC₂) at 150 °C also afforded the formation of Cu and Cu C crystallites, indicating that CuC₂ was the precursor or an intermediate in the formation of Cu C. The prepared catalysts consisting of Cu and Cu C exhibited a considerably high hydrogenation activity at low temperatures in the selective hydrogenation of acetylene in the ethylene stream. In the presence of a large excess of ethylene, acetylene was completely converted at 110 °C and atmospheric pressure with an ethane selectivity of <15%, and the conversion and selectivity were constant in a 260 h run.