ZnO/CeO2/carbon xerogel composites with direct Z-scheme heterojunctions: Enhancing photocatalytic remediation of 4-chlorophenol under visible light

Author(s)

de Moraes, Nicolas Perciani ; Sanmartin, Maite Birkett de Campos ; Rocha, Robson da Silva ; de Siervo, Abner ; Lanza, Marcos Roberto de Vasconcelos ; Reddy, D. Amaranatha ; Yu, Lianqing ; Rodrigues, Liana Alvares

• Document type: Journal article
• Source: JOURNAL OF RARE EARTHS; v. 42, n. 2, p. 9-pg., 2024-02-01.

Abstract

This paper aims to create visible light driven ternary photocatalysts using zinc oxide (ZnO), cerium (IV) oxide (CeO2), and carbon xerogel (CX) as constituent materials. The use of CeO2 is based on the creation of direct -Z -scheme heterojunctions with the ZnO and the consequent diminishing of charge recombination, whereas the carbon xerogel inclusion is predicted to minimize bandgap energy, decrease electron -hole recombination, and boost specific surface area. Furthermore, the choice of the black -wattle tannin as a carbonaceous precursor was targeted at the development of an environmentally friendly and affordable composite. The existence of the hexagonal phase of zinc oxide and cubic structure of the cerium (IV) oxide in the ternary material was confirmed by X-ray diffractometry and X-ray photoelectron spectroscopy, with the latter also suggesting chemical bonding between the ZnO and the CX due to the creation of zinc oxycarbide complexes. The inclusion of the carbon xerogel provokes a significant modification in the morphology of the ternary material, resulting in an increased surface area and smaller particle aggregates. The CX/ZnO-CeO2 ternary composite obtains the highest photocatalytic efficiency among all the materials studied, degrading 100% of 4-chlorophenol under simulated sunlight and 68% under visible radiation, after 5 h. The increased photocatalytic activity can be attributed to the formation of direct Z -scheme heterojunctions between the semiconductors, higher visible light response, and higher specific surface area, as evidenced by the results obtained by active radical scavenging, chronoamperometry, diffuse reflectance spectroscopy, and N2 adsorption -desorption isotherms. 0 2022 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 07/54829-5 - Electronic and geometric structure of nano-materials: synchrotron radiation studies
• Grantee: Richard Landers
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/16360-0 - Development of ZnO/Bi2O3/Carbon xerogel ternary composites as photocatalysts for the degradation of persistent organic pollutants
• Grantee: Nicolas Perciani de Moraes
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/10492-1 - Photocatalytic evaluation of heterojunctions semiconductor/ZnO/carbon xerogel in the photodegradation of 4-chlorophenol in both fluidized bed and batch reactors
• Grantee: Liana Alvares Rodrigues
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/10118-0 - Study and application of electrochemical technology for the analysis and degradation of endocrine interferents: materials, sensors, processes and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 07/08244-5 - Study of the magnetic properties of Pd and PdAu ultrathin films and nanoparticles by using XMCD
• Grantee: Abner de Siervo
• Support Opportunities: Regular Research Grants