Insight into the Crystal Facet Effect of {101} and {100} Facets of CeVO4 in the Photochemical Property and Photocatalysis

To investigate the photochemical property of specific crystal facets, two well-defined CeVO4 dodecahedrons with exposed {101} and {100} facets are prepared, which have distinguishing appearances and unequal {101}/{100} area ratios (A{101}/A{100}), i.e., compressed dodecahedra (CeVO4 CD, A{101}/A{100} ≈ 1) and elongated dodecahedra (CeVO4 ED, A{101}/A{100} ≈ 0.3). During the visible-light-irradiated process, the {101} and {100} facets are certified to selectively deposit photogenerated holes (h+) and electrons (e-), thus exhibiting the photooxidability and photoreducibility, respectively. Meanwhile, a surface heterojunction could form at the adjacent facet interface and facilitate the spatial separation of carriers. Benefiting from the large exposure extent of the {101} facet and the rational A{101}/A{100} (∼1), the CeVO4 CD shows a superior photocatalytic performance for the degradation of tetracycline to the CeVO4 ED. Finally, simulation calculations reveal that the energy deviations of the valence band (VB) and conduction band (CB) between CeVO4{101} and CeVO4{100} impel the photogenerated h+ and e- to transfer in opposite directions, resulting in the facet-dependent photoactivity of the CeVO4 dodecahedron.