biostudies-literatureChan SCMinistry of Science and Technology, Taiwan18500-18508https://www.ebi.ac.uk/biostudies/studies/S-EPMC9033447biostudies-literatureUnknown11(30)It was recently discovered that the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) can be completed on the {110} and {001} facets, respectively, of a 18-facet SrTiO₃ mono-crystal. The effective charge separation is attributed to the facet junction at the interface between two arbitrary anisotropic crystal planes. Theoretical estimation of the built-in potential at the facet junction can greatly improve understanding of the mechanism. This work employs density functional theory (DFT) calculations to investigate such potential at the (110)/(100) facet junction in SrTiO₃ crystals. The formation of the facet junction is verified by a calculated work function difference between the (110) and (100) planes, which form p-type and n-type segments of the junction, respectively. The built-in potential is estimated at about 2.9 V. As a result, with the ultra high built-in potential, electrons and holes can effectively transfer to different anisotropic planes to complete both photo-oxidative and photo-reductive reactions.RSC advancesThe origins of charge separation in anisotropic facet photocatalysts investigated through first-principles calculations.PMC9033447MOST 107-2221-E-007-047-MY3Cheng YLChan SCHong CWChang BKfalseThe origins of charge separation in anisotropic facet photocatalysts investigated through first-principles calculations.It was recently discovered that the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) can be completed on the {110} and {001} facets, respectively, of a 18-facet SrTiO₃ mono-crystal. The effective charge separation is attributed to the facet junction at the interface between two arbitrary anisotropic crystal planes. Theoretical estimation of the built-in potential at the facet junction can greatly improve understanding of the mechanism. This work employs density functional theory (DFT) calculations to investigate such potential at the (110)/(100) facet junction in SrTiO₃ crystals. The formation of the facet junction is verified by a calculated work function difference between the (110) and (100) planes, which form p-type and n-type segments of the junction, respectively. The built-in potential is estimated at about 2.9 V. As a result, with the ultra high built-in potential, electrons and holes can effectively transfer to different anisotropic planes to complete both photo-oxidative and photo-reductive reactions.2021-01-01T00:00:00Z2021 May2025-05-18T11:49:43.472Z2024-10-18T05:47:27.194ZS-EPMC90334473548094310.1039/d1ra01711j