Acetylene Semi-Hydrogenation at Room Temperature over Pd-Zn Nanocatalyst

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Acetylene semi-hydrogenation is crucial for producing ethylene, a key monomer in polyethylene production.
• Acetylene impurities poison Ziegler-Natta catalysts, impacting polymer quality and requiring high-temperature processing.
• Existing palladium-based catalysts often face a trade-off between conversion and selectivity at elevated temperatures.

Purpose of the Study:

• To develop a highly selective and stable catalyst for acetylene semi-hydrogenation at room temperature.
• To investigate the performance of bimetallic palladium-zinc nanoparticles for ethylene production.
• To understand the mechanistic insights governing the catalytic activity and selectivity.

Main Methods:

• Synthesis of bimetallic Pd-Zn nanoparticles capped by hexadecylamine (HDA) via co-digestive ripening.
• Acetylene semi-hydrogenation catalysis experiments conducted at room temperature and atmospheric pressure.
• Characterization using DFT calculations, Temperature Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS), and various catalytic tests.

Main Results:

• Achieved ~85% selectivity towards ethylene with high productivity (~4341 μmol g⁻¹ min⁻¹).
• Demonstrated excellent stability, maintaining >85% selectivity for over 70 hours.
• Reported the first instance of room temperature acetylene semi-hydrogenation with high conversion, selectivity, and stability.

Conclusions:

• The bimetallic Pd-Zn nanocatalyst offers a significant advancement for efficient ethylene production.
• Low-temperature synthesis and Pd-Zn interactions are key to enhanced selectivity and activity.
• The catalyst provides a stable, selective, and energy-efficient alternative for industrial acetylene conversion.