Abstract
Electrocatalytic semihydrogenation of acetylene (C(2)H(2)) provides a facile and petroleum-independent strategy for ethylene (C(2)H(4)) production. However, the reliance on the preseparation and concentration of raw coal-derived C(2)H(2) hinders its economic potential. Here, a concave surface is predicted to be beneficial for enriching C(2)H(2) and optimizing its mass transfer kinetics, thus leading to a high partial pressure of C(2)H(2) around active sites for the direct conversion of raw coal-derived C(2)H(2). Then, a porous concave carbon-supported Cu nanoparticle (Cu-PCC) electrode is designed to enrich the C(2)H(2) gas around the Cu sites. As a result, the as-prepared electrode enables a 91.7% C(2)H(4) Faradaic efficiency and a 56.31% C(2)H(2) single-pass conversion under a simulated raw coal-derived C(2)H(2) atmosphere (~15%) at a partial current density of 0.42 A cm(-2), greatly outperforming its counterpart without concave surface supports. The strengthened intermolecular π conjugation caused by the increased C(2)H(2) coverage is revealed to result in the delocalization of π electrons in C(2)H(2), consequently promoting C(2)H(2) activation, suppressing hydrogen evolution competition and enhancing C(2)H(4) selectivity.