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Nair R, Gokuladoss V. Synergistic adsorption and kinetic studies of heterostructured g-C 3N 4/TiO 2 nano-photocatalyst under visible light for enhanced CO 2 reduction. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:2495-2510. [PMID: 38063962 DOI: 10.1007/s11356-023-31163-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/17/2023] [Indexed: 01/18/2024]
Abstract
Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were synthesized using sol-gel and ultrasonic impregnation technique followed by calcination for photocatalytic CO2 reduction. The nano-photocatalysts were analyzed for their morphological, structural, and optical characteristics. Scanning electron microscopy (SEM) revealed the presence of spherical and layered sheet-like nanoparticles, as well as the occurrence of minor aggregations. The ultraviolet-visible spectroscopy (UV-vis) revealed that g-C3N4 has good photocatalytic properties with a medium band gap (2.7 eV), and TiO2 has high charge transfer potentials, robust oxidation properties, and high band gap (3.20 eV). However, the larger band gap makes it unresponsive in the visible light spectrum. In order to circumvent this constraint, a hybrid heterostructured g-C3N4/TiO2 catalyst with different compositions, viz., 1:1, 1:2, and 2:1, were fabricated using the ultrasonic impregnation technique followed by calcination process. The optical band gap of g-C3N4/TiO2 nanocomposite shows a red shift towards 2.85 eV from 3.20 eV for bare TiO2, inferring enhanced absorption in the visible light region. Further, the photocatalytic experiments were performed using visible light sources for all the catalysts. The g-C3N4/TiO2 (2:1) reported higher photocatalytic activity due to its reduced crystallite size of 12.94 nm which were investigated using X-ray diffraction analysis (XRD) and lower band gap of 2.85 eV. The study infers that hybrid photocatalyst enhances the visible light absorption, electron-hole (e - /h +) pair separation rate, and photocatalytic reduction of CO2. In addition, two adsorption models Langmuir and Freundlich were used and adsorption kinetic data were fitted to pseudo-first-order reaction for all the five catalysts. The adsorption isotherm of CO2 by g-C3N4/TiO2 (2:1) well fitted by the Freundlich adsorption equation. On the basis of adsorption magnitude (n) values (1.74), it was found that the interaction between CO2 molecules and g-C3N4/TiO2 occurs according to the chemisorption mechanism. The kinetic study infers that the highest value of apparent rate constant (kapp) was exhibited by g-C3N4/TiO2 (2:1), which indicates that the products predominate at equilibrium.
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Affiliation(s)
- Rishika Nair
- School of Electrical Engineering, Vellore Institute of Technology (VIT), Vellore, 632 014, India
- CO2 Research and Green Technology Centre, Vellore Institute of Technology (VIT), Vellore, 632 014, India
| | - Velvizhi Gokuladoss
- CO2 Research and Green Technology Centre, Vellore Institute of Technology (VIT), Vellore, 632 014, India.
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Li Y, Chen H, Wang L, Wu T, Wu Y, He Y. KNbO 3/ZnO heterojunction harvesting ultrasonic mechanical energy and solar energy to efficiently degrade methyl orange. ULTRASONICS SONOCHEMISTRY 2021; 78:105754. [PMID: 34530388 PMCID: PMC8445898 DOI: 10.1016/j.ultsonch.2021.105754] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 05/14/2023]
Abstract
In this paper, KNbO3/ZnO nanocomposite was synthesized and used in piezo/photocatalytic degradation of methyl orange (MO) under simulated sunlight and ultrasonic vibration. Under simulated solar light, the optimal KNbO3/ZnO sample presented a MO degradation rate of 0.047 min-1, which is 2.47 times higher than that of ZnO. The promotion effect of KNbO3 on ZnO was also observed in the piezoelectric catalytic reaction. In addition, the co-utilization of solar and mechanical energy can further increase the MO degradation rate. Piezoelectric property and photoresponse capability are the origins of the piezo/photo catalytic behavior of the KNbO3/ZnO composite. Owing to the different band potentials of KNbO3 and ZnO, the electric potential field at their interface can drive the second distribution of the photo/piezoinduced charge carriers and hence promote the photo/piezocatalytic activity. This phenomenon was verified by the analysis on transient photocurrent and piezocurrent response. Trapping experiments on reactive species were also conducted. Superoxide radicals, holes, and hydroxyl radicals were found to be the main reactive species during the photo/piezocatalytic reaction. Recycling test showed that the KNbO3/ZnO composite exhibited good catalytic stability during six consecutive uses. Given its advantages of good catalytic activity and stability, the synthesized KNbO3/ZnO nanocomposite material has great potential in the further use of solar and mechanical energy to develop new water purification technologies.
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Affiliation(s)
- Yi Li
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China
| | - Huafeng Chen
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China
| | - Linkun Wang
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China
| | - Tiantian Wu
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China
| | - Ying Wu
- Key Laboratory of the Ministry of Education for Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China.
| | - Yiming He
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua 321004, China; Key Laboratory of the Ministry of Education for Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China.
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Koutavarapu R, Tamtam MR, Rao MC, Peera SG, Shim J. Recent progress in transition metal oxide/sulfide quantum dots-based nanocomposites for the removal of toxic organic pollutants. CHEMOSPHERE 2021; 272:129849. [PMID: 33582511 DOI: 10.1016/j.chemosphere.2021.129849] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/06/2021] [Accepted: 01/30/2021] [Indexed: 06/12/2023]
Abstract
Water is an essential solvent that is extremely necessary for the survival of life. Water pollution due to the increased utilization of water for various processes, including domestic and industrial activities, poses a special threat that contaminates both surface and ground water. In recent years, advanced oxidation processes (AOPs) have been applied to deal with wastewater problems, which is a green method used to oxidize organic contaminants with strong oxidative radical species. Among the AOPs, photocatalytic technology is one of the most promising strategies for wastewater cleaning, which fulfills the aims of environmentally friendly and sustainable development. Owing to their unique electronic, optical, and structural properties, nanoscale semiconductors have received substantial interest as materials for AOPs, particularly inspired by their superb quantum confinement effects and large surface-area-to-volume ratio, which are essential for catalytic reaction kinetics. Recent advancements have revealed that semiconductor nanocrystals, known as quantum dots (QDs), are newly emerging zero-dimensional (0-D) nanomaterials, which have garnered much attention owing to their special physiochemical characteristics such as high conductivity, thermo-chemical and opto-mechanical stability, high adsorption coefficients, and, most importantly, their admirable recyclability. In this review, we provide a clear understanding of the importance of semiconductor QD-based nanocomposites in the degradation of organic pollutants, in addition to the mechanism involved in the reaction process. Following this, the enhancement of different materials, such as metal oxides and metal sulfide QD-based nanocomposites, is discussed in the context of combating environmental pollution.
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Affiliation(s)
| | - Mohan Rao Tamtam
- Chemical Engineering Department, Debre Berhan University, Debre Berhan 445, Ethiopia
| | - M C Rao
- Department of Physics, Andhra Loyola College, Vijayawada, 520-008, Andhra Pradesh, India.
| | - Shaik Gouse Peera
- Department of Environmental Science and Engineering, Keimyung University, Daegu, 42602, Republic of Korea.
| | - Jaesool Shim
- School of Mechanical Engineering, Yeungnam University, Gyeongsan, 712-749, Republic of Korea.
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Patial S, Kumar R, Raizada P, Singh P, Van Le Q, Lichtfouse E, Le Tri Nguyen D, Nguyen VH. Boosting light-driven CO 2 reduction into solar fuels: Mainstream avenues for engineering ZnO-based photocatalysts. ENVIRONMENTAL RESEARCH 2021; 197:111134. [PMID: 33836181 DOI: 10.1016/j.envres.2021.111134] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/28/2021] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
The realization of artificial photosynthesis in the photocatalytic CO2 transformation into valuable chemicals or solar fuels, such as CO, CH4, HCOOH, and CH3OH, by solar-light harvesting is a promising solution to both global-warming and energy-supply issues. Recently, zinc oxide (ZnO) has emerged as an excellent oxidative photocatalyst among non-titanium metal oxides due to its availability, outstanding semiconducting and optical properties, non-toxicity, affordability, and ease of synthesis. However, ZnO wide bandgap and inability to absorb in the visible region has demanded particular modification for its practical use as a sustainable photocatalyst. This review provides a panorama of the latest advancement on ZnO photocatalysis for CO2 reduction with an overview of fundamental aspects. Various modification strategies such as transition metal and non-metal doping, loading of plasmonic metals, and surface vacancy engineering for tunning the properties and improving the performance of ZnO are elaborated. Composites or hetero-structuralization-based Z-scheme formation is also presented along with a detailed photocatalytic reduction mechanism. Moreover, a new novel Step-scheme (S-scheme) heterostructure modification with a charge transfer pathway mechanism is also highlighted. Finally, the key challenges and new directions in this field are proposed to provide a new vision for further improvement for ZnO-based photocatalytic CO2 conversion.
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Affiliation(s)
- Shilpa Patial
- School of Advanced Chemical Sciences, Faculty of Basic Sciences, Shoolini University, Solan (HP), 173229, India
| | - Rohit Kumar
- School of Advanced Chemical Sciences, Faculty of Basic Sciences, Shoolini University, Solan (HP), 173229, India
| | - Pankaj Raizada
- School of Advanced Chemical Sciences, Faculty of Basic Sciences, Shoolini University, Solan (HP), 173229, India.
| | - Pardeep Singh
- School of Advanced Chemical Sciences, Faculty of Basic Sciences, Shoolini University, Solan (HP), 173229, India
| | - Quyet Van Le
- Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam
| | - Eric Lichtfouse
- Aix-Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, 13100, France; International Research Centre for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, PR China
| | - Dang Le Tri Nguyen
- Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| | - Van-Huy Nguyen
- Faculty of Biotechnology, Binh Duong University, Thu Dau Mot, Vietnam.
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Liu C, Sun Y, Feng Y, Han Z, Zhao Y, Zhang Q, Zou Z. Constructing N-Doped KNb3O8/g-C3N4 Composite for Efficient Photocatalytic H2 Generation and Degradation under Visible Light Irradiation. Catal Letters 2020. [DOI: 10.1007/s10562-020-03188-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Jo YK, Lee JM, Son S, Hwang SJ. 2D inorganic nanosheet-based hybrid photocatalysts: Design, applications, and perspectives. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2019. [DOI: 10.1016/j.jphotochemrev.2018.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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