TY - JOUR

T1 - Effect of the Type of Heterostructures on Photostimulated Alteration of the Surface Hydrophilicity

T2 - TiO2 /BiVO4 vs. ZnO/BiVO4 Planar Heterostructured Coatings

AU - Maevskaya, Maria V.

AU - Rudakova, Aida V.

AU - Koroleva, Alexandra V.

AU - Sakhatskii, Aleksandr S.

AU - Emeline, Alexei V.

AU - Bahnemann, Detlef W.

N1 - Funding Information: Funding: The reported study was funded by RFBR, project number 19-32-90111.

PY - 2021/12

Y1 - 2021/12

N2 - Here, we report the results of comparative studies of the photostimulated hydrophilic behavior of heterostructured TiO2 /BiVO4 and ZnO/BiVO4, and monocomponent TiO2 and ZnO nanocoating surfaces. The chemical composition and morphology of the synthesized nanocoat-ings were characterized by XPS, SEM, and AFM methods. The electronic energy structure of the heterostructure components (band gap, top of the valence band, bottom of the conduction band, and Fermi level position) was determined on the basis of experimental results obtained by XPS, UV-V absorption spectroscopy and Kelvin probe methods. According to their electronic energy structure, the ZnO/BiVO4 and TiO2 /BiVO4 heterostructures correspond to type I and type II het-erostructures, respectively. The difference in the type of heterostructures causes the difference in the charge transfer behavior at heterojunctions: the type II TiO2 /BiVO4 heterostructure favors and the type I ZnO/BiVO4 heterostructure prevents the photogenerated hole transfer from BiVO4 to the outer layer of the corresponding metal oxide. The results of the comparative studies show that the interaction of the photogenerated holes with surface hydroxy-hydrated multilayers is responsible for the superhydrophilic surface conversion accompanying the increase of the surface free energy and work function. The formation of the type II heterostructure leads to the spectral sensitization of the photostimulated surface superhydrophilic conversion.

AB - Here, we report the results of comparative studies of the photostimulated hydrophilic behavior of heterostructured TiO2 /BiVO4 and ZnO/BiVO4, and monocomponent TiO2 and ZnO nanocoating surfaces. The chemical composition and morphology of the synthesized nanocoat-ings were characterized by XPS, SEM, and AFM methods. The electronic energy structure of the heterostructure components (band gap, top of the valence band, bottom of the conduction band, and Fermi level position) was determined on the basis of experimental results obtained by XPS, UV-V absorption spectroscopy and Kelvin probe methods. According to their electronic energy structure, the ZnO/BiVO4 and TiO2 /BiVO4 heterostructures correspond to type I and type II het-erostructures, respectively. The difference in the type of heterostructures causes the difference in the charge transfer behavior at heterojunctions: the type II TiO2 /BiVO4 heterostructure favors and the type I ZnO/BiVO4 heterostructure prevents the photogenerated hole transfer from BiVO4 to the outer layer of the corresponding metal oxide. The results of the comparative studies show that the interaction of the photogenerated holes with surface hydroxy-hydrated multilayers is responsible for the superhydrophilic surface conversion accompanying the increase of the surface free energy and work function. The formation of the type II heterostructure leads to the spectral sensitization of the photostimulated surface superhydrophilic conversion.

KW - Charge separation

KW - Charge transfer

KW - Heterojunctions

KW - Heterostructures

KW - Metal oxide surfaces

KW - Photostimulated hydrophilicity

KW - Surface energy

KW - Work function

UR - http://www.scopus.com/inward/record.url?scp=85119599871&partnerID=8YFLogxK

U2 - 10.3390/catal11121424

DO - 10.3390/catal11121424

M3 - Article

AN - SCOPUS:85119599871

VL - 11

JO - CATALYSTS

JF - CATALYSTS

SN - 2073-4344

IS - 12

M1 - 1424

ER -