A density functional theory exploration on the Zn catalyst for acetylene hydration

Area of Science:

• Catalysis
• Physical Chemistry
• Materials Science

Background:

• Acetylene hydration to acetaldehyde is a long-standing industrial process.
• A detailed molecular-level understanding of the reaction mechanism is currently lacking.

Purpose of the Study:

• To systematically investigate the reaction mechanisms of acetylene hydration on ZnCl2, Zn(OH)Cl, and Zn(OH)2 catalysts.
• To elucidate the role of catalyst structure and functional groups in determining reaction pathways and efficiency.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Fukui functions, condensed Fukui functions, and Hirshfeld charges were used to identify active sites and electron transfer.

Main Results:

• Catalysts with hydroxyl groups showed lower adsorption performance compared to those without.
• Zn(OH)Cl and Zn(OH)2 catalysts facilitate the reaction via a one-shift H2O molecule transfer route.
• The activation energy is determined by the energy required to break the O-H bond in water.

Conclusions:

• The activation barrier follows the order: Zn(OH)Cl ≈ Zn(OH)2 < ZnCl2.
• Zn(OH)Cl and Zn(OH)2 are identified as promising catalysts for acetylene hydration due to lower activation barriers.
• Understanding the molecular-level mechanisms can guide the development of more efficient catalysts.