Conversion of Acetylene to Benzene over Palladium Single-Crystal Surfaces. 2. The Effect of Additives

Article abstract of DOI:10.1021/j100403a030

The conversion of acetylene to benzene over palladium single-crystal surfaces ((111), (100), and (110)) modified with submonolayer quantities of silicon, phosphorus, sulfur, chlorine, and potassium has been studied under both ultrahigh vacuum and atmospheric pressure conditions.At atmospheric pressures electron-donating additives enhance the rate of benzene formation and electron-accepting additives reduce the rate.Potassium and silicon reduce the amount of surface carbon that accumulates during the reaction and thereby increase the rate of benzene formation relative to the undoped surface.The general trends of the (111), (100), and (110) faces indicate that at low pressures potassium suppresses, silicon and phosphorus enhance, and sulfur and chlorine leave unchanged the benzene yield.Silicon on the (100) face showed the greatest enhancement in the benzene yield possibly due to surface compound formation.