Cation-exchange mediated synthesis of hydrogen and sodium titanates heterojunction: Theoretical and experimental insights toward photocatalyic mechanism

Author(s):Show less -

Iani, Isabela M. ^[1] ; Teodoro, Vinicius ^[2] ; Marana, Naiara L. ^[3] ; Coleto Jr, Ubirajara ; Sambrano, Julio R. ^[3] ; Simoes, Alexandre Z. ^[4] ; Teodoro, Marcio D. ^[5] ; Longo, Elson ^[2] ; Perazolli, Leinig A. ^[1] ; Amoresi, Rafael A. C. ^[4] ; Zaghete, Maria Aparecida ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, LIEC Chem Inst, BR-14800060 Araraquara, SP - Brazil

^[2] Sao Carlos Fed Univ UFSCar, LIEC Dept Chem, BR-13565905 Sao Carlos, SP - Brazil

^[3] Sao Paulo State Univ, UNESP, Modeling & Mol Simulat Grp, BR-17033360 Bauru, SP - Brazil

^[4] UNESP, Fac Engn Guaratingueta, BR-12516410 Guaratingueta, SP - Brazil

^[5] Sao Carlos Fed Univ UFSCar, Dept Phys, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Applied Surface Science; v. 538, FEB 1 2021.
• Web of Science Citations: 0

Abstract

Na2Ti3O7/H2Ti3O7 heterojunction nanotubes were obtained through the microwave-assisted hydrothermal method (MAH) with different band gap energy engineering. This study aimed to synthesize sodium titanate nanotubes and evaluate the influence of H+ insertion on their photocatalytic properties. Heterojunctions were identified by X-ray diffraction, Raman spectroscopy and high-resolution transmission electron microscopy, and their electronic levels and defects were investigated using diffuse reflectance and photoluminescence spectroscopies in the UV-Vis region. The cation exchange process promotes the formation of Na2Ti3O7/H2Ti3O7 heterojunction with coexistence of both phases in the nanotube. Photocatalytic results of Rhodamine-B (Rh-B) dye discoloration show that the prepared materials have activity under visible and UV light irradiation, and are dependent on the proportion of hydrogen and sodium-titanate phases present. The material with highest sodium concentration showed discoloration with a half-life time of 23 min under visible light irradiation. Theoretical results reveal the heterojunction band offset as a staggered gap, with the effective bandgap occurring between the O-2p of Na2Ti3O7 and Ti-3d of H2Ti3O7. The charge carrier transfer mechanism in the heterojunctions is well described by Z-scheme, with H2Ti3O7 and Na2Ti3O7 as the main oxidation and reduction phases for dye discoloration. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 19/12430-6 - Computational study of properties of pure and functionalized multiwalled nanotubes
• Grantee: Naiara Letícia Marana
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 19/12114-7 - Nanomaterials of sodium titanate: structure, morphology and photocatalytic and sensor properties
• Grantee: Isabela Marcondelli Iani
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 17/19143-7 - An experimental theoretical approach of conduction mechanisms and interface defects of heterostructure sensors based on P-N and N-N semiconductors from CeO2 matrices
• Grantee: Rafael Aparecido Ciola Amoresi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/24405-0 - Study of the photocatalytic and photoluminescent properties of TiO2 morphologies decorated with Ceriun
• Grantee: Isabela Marcondelli Iani
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 19/08928-9 - Modeling and simulations of porous inorganic nanotubes functionalization
• Grantee: Julio Ricardo Sambrano
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/25500-4 - Functionalization of semiconductor nanotubes via interfaces and gas adsorption: a computational approach
• Grantee: Naiara Letícia Marana
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/01914-0 - Functionalizing the optical emission in quantum tunneling nanostructures in different spectral intervals
• Grantee: Marcio Daldin Teodoro
• Support Opportunities: Regular Research Grants