Insight into the Crystal Facet Effect of {101} and {100} Facets of CeVO 4 in the Photochemical Property and Photocatalysis.

To investigate the photochemical property of specific crystal facets, two well-defined CeVO 4 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 (CeVO 4 CD, A {101} /A {100} ≈ 1) and elongated dodecahedra (CeVO 4 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 CeVO 4 CD shows a superior photocatalytic performance for the degradation of tetracycline to the CeVO 4 ED. Finally, simulation calculations reveal that the energy deviations of the valence band (VB) and conduction band (CB) between CeVO 4 {101} and CeVO 4 {100} impel the photogenerated h + and e - to transfer in opposite directions, resulting in the facet-dependent photoactivity of the CeVO 4 dodecahedron.