Facet-dependent electrooxidation of propylene into propylene oxide over Ag 3 PO 4 crystals.

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 Ag 3 PO 4 for the electrooxidation of propylene into propylene oxide. The Ag 3 PO 4 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 Ag 3 PO 4 rhombic dodecahedra with (110) facets and tetrahedra with (111) facets, respectively. The theoretical calculations reveal that the largest polarization of propylene on Ag 3 PO 4 (100) facets is beneficial to break the symmetric π bonding and facilitate the formation of C-O bond. Meanwhile, Ag 3 PO 4 (100) facets exhibit the lowest adsorption energies of * C 3 H 6 and * OH, inducing the lowest energy barrier of the rate-determining step and thus accounting for the highest catalytic performance.