Modulating a Three-Phase Interface Catalytic Microenvironment via Hydrophilic Ionic Liquids in Electrochemical Acetylene Selective Hydrogenation
Chunxiao Jin, Shuwei Zhou, Siyu Pei, Zikun Wang, Shitong Liu, Yuxue Yue, Saisai Wang, Renqin Chang, Jia Zhao, Xiao‐Nian Li
Abstract
Diverse combinations of ionic liquids (ILs), anions, and cations can effectively regulate the properties of the three-phase interface catalytic microenvironment, which determine the dissolution and mass transfer of reaction gases. Herein, we found that hydrophilic ILs can enrich trace C 2 H 2 in an ethylene-rich stream and create an acetylene-rich microenvironment for Cu nanoparticle (Cu NP) active sites. Increasing the solubility of C 2 H 2 at the three-phase interface can effectively improve the activity of the electrochemical acetylene selective hydrogenation reaction (EASR). The full conversion of trace C 2 H 2 molecules in the ethylene-rich stream effectively solves the problem of preparing polymer-grade ethylene in industrial production. However, too high solubility of C 2 H 2 at the three-phase interface will also lead to the formation of C4 byproducts. The relationship between C 2 H 4 selectivity and K (C 2 H 4 )/ K (C 2 H 2 ) is a volcano-shaped curve, which provides valuable descriptors. Finally, the BmimCl/Cu catalysts achieved a C 2 H 2 concentration as low as 0 ppm in the product, with selectivity over 90% in 125 h of long-term evaluation under the ethylene-rich stream.