Identification of Copper as an Ideal Catalyst for Electrochemical Alkyne Semi-hydrogenation

Selective
removal of ∼1% acetylene impurity from ethylene
is an essential process to prevent the poisoning of the Ziegler–Natta
catalyst in polyethylene production. Developing an earth-abundant
catalyst to replace Pd and a new approach to reduce energy consumption
represents an immense challenge in this field. Herein, we present
an atomic understanding of the trend in electrocatalytic acetylene
semi-hydrogenation over 12 transition metals with systematic density
functional theory calculations and the computational hydrogen electrode
model. Copper stands out and is theoretically identified as the ideal
metal for electrocatalytic acetylene conversion to ethylene with a
suppressed hydrogen evolution reaction. Our theoretically predicted
Cu catalyst has been successfully synthesized and tested to be superior
for selective alkyne semi-hydrogenation experimentally, which greatly
validates our computational framework for the rational design of the
catalyst. This work not only illustrates the key factors determining
the activity and selectivity but also provides new suggestions for
further optimization of this environmentally benign and economically
feasible route for ambient alkyne semi-hydrogenation.