Investigation of the structure activity relationship of palladium-bismuth catalyst in acetylene hydrogenation

Abstract

BackgroundEthylene is an important raw material in petrochemical industry. Semi-hydrogenation of acetylene in an ethylene is an industrially important process. Conventional supported monometallic Pd catalysts offer high acetylene conversion, but they suffer from very low selectivity to ethylene due to over-hydrogenation.PurposeThis study aims to prepare a catalyst with high acetylene conversion and simultaneous selectivity to ethylene, surpassing conventional Pd catalysts, and explore the structure activity relationship of palladium-bismuth catalyst in acetylene hydrogenation.MethodsFirstly, PdBi/SiO2 catalyst was synthesized via a deposition-precipitation method for industrial hydrogenation of acetylene to ethylene. Then, comparison of catalytic activity and selectivity with traditional catalysts in the semi hydrogenation reaction of acetylene was conducted. Finally, the X-ray Absorption Fine Structure (XAFS), High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM), and X-ray Energy Dispersive Spectroscopy (EDS) were employed to explore the reaction mechanism.ResultsCompared with the Pd catalyst, PdBi/SiO2 catalyst exhibits increased reactivity at a lower temperature, with 100% acetylene conversion and 90% selectivity.ConclusionsThe Pd-Bi alloys structure is confirmed to effectively inhibit the formation of PdHx, weaken the cracking rate of hydrogen and the adsorption of ethylene on palladium surface, and inhibit the excessive hydrogenation of ethylene to produce by-product ethane. The simple synthesis PdBi structure provides new ideas and insights for industrial catalysts.

Keywords

• x-ray absorption fine structure
• catalyst
• sio2
• acetylene hydrogenation