Facet-dependent electrooxidation of propylene into propylene oxide over Ag3PO4 crystals

Abstract

The electrooxidation of propylene into propylene oxide under ambient conditions represents an attractive approach toward propylene oxide. However, this process suffers from a low yield rate over reported electrocatalysts. In this work, we develop an efficient electrocatalyst of Ag₃PO₄ for the electrooxidation of propylene into propylene oxide. The Ag₃PO₄ cubes with (100) facets exhibit the highest yield rate of 5.3 g_PO m^-2 h^-1 at 2.4 V versus reversible hydrogen electrode, which is 1.6 and 2.5 times higher than those over Ag₃PO₄ rhombic dodecahedra with (110) facets and tetrahedra with (111) facets, respectively. The theoretical calculations reveal that the largest polarization of propylene on Ag₃PO₄ (100) facets is beneficial to break the symmetric π bonding and facilitate the formation of C-O bond. Meanwhile, Ag₃PO₄(100) facets exhibit the lowest adsorption energies of ^*C₃H₆ and ^*OH, inducing the lowest energy barrier of the rate-determining step and thus accounting for the highest catalytic performance.