Premium
Strong Facet Effects on Interfacial Charge Transfer Revealed through the Examination of Photocatalytic Activities of Various Cu 2 O–ZnO Heterostructures
Author(s) -
Wu SzuChieh,
Tan ChihShan,
Huang Michael H.
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201604635
Subject(s) - materials science , heterojunction , dodecahedron , band bending , octahedron , photocatalysis , semiconductor , facet (psychology) , methyl orange , band gap , crystallography , exciton , acceptor , nanotechnology , crystal structure , condensed matter physics , optoelectronics , catalysis , chemistry , psychology , social psychology , biochemistry , physics , personality , big five personality traits
Confirming the photocatalytic inactivity of Cu 2 O nanocubes through the formation of Au‐decorated–Cu 2 O heterostructures, spiky ZnO nanostructures are grown on Cu 2 O cubes, octahedra, and rhombic dodecahedra to demonstrate that charge transfer across semiconductor heterojunctions is also strongly facet dependent. Unintended CuO formation in the growth of ZnO on perfect Cu 2 O cubes makes them slightly active toward methyl orange photodegradation. Under optimal ZnO growth conditions without CuO presence, Cu 2 O cubes remain inactive, while rhombic dodecahedra show an enhanced photocatalytic activity due to better charge transfer according to normal Cu 2 O–ZnO band alignment. Surprisingly, photocatalytically active Cu 2 O octahedra become inactive after ZnO deposition. An extensive interfacial microscopic examination reveals preferential formation of the ZnO (101) planes on the {111} surfaces of Cu 2 O octahedra, while different ZnO lattice planes are observed to deposit on Cu 2 O cubes and rhombic dodecahedra. The photocatalytic inactivity of ZnO‐decorated Cu 2 O octahedra is explained in terms of an unfavorable band alignment arising from an unusual degree of band bending for the ZnO {101} face relative to the band energy of the Cu 2 O {111} surface. The efficiency of charge transfer across semiconductor heterojunctions strongly depends on the band edge energies of the contacting planes.