Photocatalytic degradation of 2,4-dichlorophenol on ZrO2–TiO2: influence of crystal size, surface area, and energetic states

• Published in: Journal of materials science. Materials in electronics Vol. 31; no. 4; pp. 3332 - 3341
• Main Authors: Guerrero-Araque, Diana, Ramírez-Ortega, David, Acevedo-Peña, Próspero, Zanella, Rodolfo, Gómez, Ricardo
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-02-2020; Springer Nature B.V
• Subjects: Catalytic activity; Characterization and Evaluation of Materials; Charge transfer; Chemistry and Materials Science; Crystallites; Electron traps; Heterostructures; Hydroxyl radicals; Irradiation; Materials Science; Optical and Electronic Materials; Oxidation; Photocatalysis; Photodegradation; Photoelectrons; Roasting; Sol-gel processes; Spectrum analysis; Surface area; Thermal analysis; Titanium dioxide; Ultraviolet radiation; Zirconium dioxide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-020-02881-2

ZrO
2
–TiO
2
heterostructure with 5 mol% of ZrO
2
was synthesized by the sol–gel method and calcined at different temperatures (300–600 °C). The photocatalysts were characterized by thermal analysis, X-ray diffraction, physisorption of N
2
, diffuse reflectance spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity was tested for the removal of 2,4-dichlorophenol under ultraviolet irradiation, being the materials exhibiting the best performance those calcined at 400 °C and 500 °C with 99% and 98% of degradation, respectively, after 150 min under irradiation. This behavior was related to a smaller crystallite size, higher surface area, and significant hydroxyl radicals produced. The (photo)electrochemical study showed that temperatures of 400 °C and 500 °C also generated an optimum amount of energetic states that act as electron traps and decrease the electron–hole pair recombination, favoring the oxidation of 2,4-dichlorophenol. However, at 300 °C and 600 °C, these energetic states act as an energy barrier that reduces the effective charge transfer and therefore decreases the photocatalytic activity of the materials.