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Li G, Lian Z, Lyu Q, Zhu C, Liu Z, Zhang S, Zhong Q. Built-in electric field mediated S-scheme charge migration and Co-N4(II) sites in cobalt phthalocyanine/MIL-68(In)-NH 2 heterojunction for boosting photocatalytic nitric oxide oxidation. J Colloid Interface Sci 2024; 675:549-559. [PMID: 38986328 DOI: 10.1016/j.jcis.2024.07.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/14/2024] [Accepted: 07/04/2024] [Indexed: 07/12/2024]
Abstract
The efficiency of photocatalytic Nitric Oxide(NO) oxidation is limited by the lack of oxygen(O2) active sites and poor charge carrier separation. To address this challenge, we developed a molecular Cobalt Phthalocyanine modified MIL-68(In)-NH2 photocatalyst with a robust Built-in electric field(BIEF). In the 2 % CoPc-MIN sample, the BIEF strength is increased by 3.54 times and 5.83 times compared to pristine CoPc and MIL-68(In)-NH2, respectively. This BIEF facilitates the efficient S-scheme charge transfer, thereby enhancing photogenerated carrier separation. Additionally, the Co-N4(II) sites in CoPc can effectively trap the separated photoexcited electrons in the S-scheme system. In addition, the Co-N4(II) sites can also serve as active sites for O2 adsorption and activation, promoting the generation of superoxide radical (O2-), thereby driving the direct conversion of NO to nitrate(NO3-). Consequently, the 2 % CoPc-MIN sample exhibits a remarkable photocatalytic NO removal efficiency of 79.37 % while effectively suppressing the formation of harmful by-product nitrogen dioxide(NO2) to below 3.5 ppb. This study provides a feasible strategy for designing high-efficiency O2 activation photocatalysts for NO oxidation.
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Affiliation(s)
- Guojun Li
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China
| | - Zheng Lian
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China
| | - Qiuqiu Lyu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China
| | - Chenyu Zhu
- State Key Laboratory of Coordination Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Zhinian Liu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China
| | - Shule Zhang
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China.
| | - Qin Zhong
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China.
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Xue T, Li J, Chen L, Li K, Hua Y, Yang Y, Dong F. Photocatalytic NO x removal and recovery: progress, challenges and future perspectives. Chem Sci 2024; 15:9026-9046. [PMID: 38903227 PMCID: PMC11186336 DOI: 10.1039/d4sc01891e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/18/2024] [Indexed: 06/22/2024] Open
Abstract
The excessive production of nitrogen oxides (NO x ) from energy production, agricultural activities, transportation, and other human activities remains a pressing issue in atmospheric environment management. NO x serves both as a significant pollutant and a potential feedstock for energy carriers. Photocatalytic technology for NO x removal and recovery has received widespread attention and has experienced rapid development in recent years owing to its environmental friendliness, mild reaction conditions, and high efficiency. This review systematically summarizes the recent advances in photocatalytic removal, encompassing NO x oxidation removal (including single and synergistic removal and NO3 - decomposition), NO x reduction to N2, and the emergent NO x upcycling into green ammonia. Special focus is given to the molecular understanding of the interfacial nitrogen-associated reaction mechanisms and their regulation pathways. Finally, the status and the challenges of photocatalytic NO x removal and recovery are critically discussed and future outlooks are proposed for their potential practical application.
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Affiliation(s)
- Ting Xue
- Research Center for Carbon-Neutral Environmental & Energy Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Jing Li
- Research Center for Carbon-Neutral Environmental & Energy Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Lvcun Chen
- School of Environmental Science and Engineering, Southwest Jiaotong University Chengdu 611756 China
| | - Kanglu Li
- School of Environmental Science and Engineering, Southwest Jiaotong University Chengdu 611756 China
| | - Ying Hua
- Research Center for Carbon-Neutral Environmental & Energy Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China Chengdu 611731 China
| | - Yan Yang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou 510006 China
- Synergy Innovation Institute of GDUT Shantou 515041 Guangdong China
| | - Fan Dong
- Research Center for Carbon-Neutral Environmental & Energy Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China Chengdu 611731 China
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Xu P, Li Z, Guo S, Jones DL, Wang J, Han Z, Zou J. Lower soil nitrogen-oxide emissions associated with enhanced denitrification under replacing mineral fertilizer with manure in orchard soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171192. [PMID: 38401727 DOI: 10.1016/j.scitotenv.2024.171192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/26/2024] [Accepted: 02/21/2024] [Indexed: 02/26/2024]
Abstract
Emerging evidence suggests that replacing mineral fertilizers with organic livestock manure can effectively suppress reactive gaseous nitrogen (N) emissions from soils. However, the extent of this mitigation potential and the underlying microbial mechanisms in orchards remain unclear. To address this knowledge gap, we measured nitrous and nitric oxide (N2O and NO) emissions, microbial N cycling gene abundance, and N2O isotopomer ratios in pear and citrus orchards under three different fertilization regimes: no fertilization, mineral fertilizer, and manure plus mineral fertilizer. The results showed that although manure application caused large transient peaks of N2O, it reduced cumulative emissions of N2O and NO by an average of 20 % and 17 %, respectively, compared to the mineral fertilizer treatment. Partial replacement of mineral fertilizers with manure enhanced the contribution of AOA to nitrification and reduced the contribution of AOB, thus reducing N2O emissions from nitrification. Isotope analysis suggested that the pathway for N2O production in the soils of both orchards was dominated by bacterial denitrification and nitrifier denitrification. The manure treatment reduced the ratio of denitrification products. Additionally, the dual isotope mixing model results indicated that partially replacing mineral fertilizers with manure could promote soil denitrification, resulting in more N2O being reduced. N-oxide emissions were on average 67 % higher in the pear orchard than in the citrus orchard, probably due to the differences in soil physicochemical properties and growth habits between the two orchards. These findings underscore the potential of partially replacing mineral fertilizers with organic manure in orchards to reduce gaseous N emissions, contributing to the transition towards environmentally sustainable and climate-smart agricultural practices.
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Affiliation(s)
- Pinshang Xu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhutao Li
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Shumin Guo
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Davey L Jones
- School of Environmental and Natural Sciences, Bangor University, Bangor, Gwynedd, LL57192UW, UK; SoilsWest, Centre for Sustainable Farming Systems, Food Futures Institute, Murdoch University, Murdoch, WA, 6150, Australia
| | - Jinyang Wang
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhaoqiang Han
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China.
| | - Jianwen Zou
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China
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4
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Sánchez-Rodríguez AR, Gómez-Álvarez E, Méndez JM, Skiba UM, Jones DL, Chadwick DR, Del Campillo MC, Fernandes RB, Kleffmann J, Barrón V. Photocatalytic fixation of NO x in soils. CHEMOSPHERE 2023; 338:139576. [PMID: 37474039 DOI: 10.1016/j.chemosphere.2023.139576] [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: 05/19/2023] [Revised: 07/04/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Nitrogen oxides (NOx = NO + NO2) are important atmospheric pollutants that are directly harmful to human health. Recently in urban and industrial areas, synthetic materials have been developed and deployed to photocatalytically oxidize NOx to nitrate (NO3-) in order to improve air quality. We show that the natural presence of small amounts (≤5%) of titanium oxides, such as anatase and rutile, can also drive NOx oxidation to nitrate in soils under UV-visible irradiation. The NO uptake coefficients ranged between 0.1 × 10-6 for sandy soils to 6.4 × 10-5 in the case of tropical clay soils; the latter comparable in efficiency to current industrial man-made catalysts. This photocatalytic N-fixation mechanism offers a new strategy for NOx mitigation from the atmosphere by transforming it into nitrate, and simultaneously provides an energy efficient source of essential fertilizer to agriculture.
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Affiliation(s)
| | | | - José M Méndez
- Department of Agronomy, Universidad de Córdoba, 14071, Córdoba, Spain
| | - Ute M Skiba
- UK Centre for Ecology & Hydrology, Edinburgh, UK
| | - Davey L Jones
- Food Futures Institute, Murdoch University, WA 6105, Perth, Australia; School of Natural Sciences, Bangor University, UK
| | | | | | | | - Jörg Kleffmann
- Department of Physical and Theoretical Chemistry, Faculty for Mathematics and Natural Sciences, University of Wuppertal, 42097, Wuppertal, Germany
| | - Vidal Barrón
- Department of Agronomy, Universidad de Córdoba, 14071, Córdoba, Spain.
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Chang F, Zhao S, Lei Y, Wang X, Dong F, Zhu G, Kong Y. Jointly augmented photocatalytic NO removal by S-scheme Bi 12SiO 20/Ag 2MoO 4 heterojunctions with surface oxygen vacancies. J Colloid Interface Sci 2023; 649:713-723. [PMID: 37385036 DOI: 10.1016/j.jcis.2023.06.168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/13/2023] [Accepted: 06/24/2023] [Indexed: 07/01/2023]
Abstract
The deep oxidation of NO molecules to NO3- species with the avoidance of toxic NO2 generation is a big and challengeable concern, which can be solved by the rational design and construction of catalytic systems with satisfactory structural and optical features. For such, in this investigation binary composites Bi12SiO20/Ag2MoO4 (BSO-XAM) were fabricated through a facile mechanical ball-milling route. From microstructural and morphological analyses, heterojunction structures with surface oxygen vacancies (OVs) were simultaneously created, contributing to the enhanced visible-light absorption, reinforced migration and separation of charge carries, and further boosted generation of reactive species such as superoxide radicals and singlet oxygen. Based on the density-functional theory (DFT) calculations, surface OVs induced the strengthened adsorption and activation of O2, H2O, and NO molecules and oxidation of NO to NO2, while heterojunction structures were beneficial for the continuous oxidation of NO2 to NO3- species. Thus, the heterojunction structures with surface OVs synergistically guaranteed the augmented photocatalytic NO removal and constrained NO2 generation of BSO-XAM through a typical S-scheme model. This study may provide scientific guidances for the photocatalytic control and removal of NO at ppb level by Bi12SiO20-based composites through the mechanical ball-milling protocol.
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Affiliation(s)
- Fei Chang
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Shanshan Zhao
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Yibo Lei
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Xiaomeng Wang
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Fan Dong
- Research Center for Environmental Science & Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, PR China
| | - Gangqiang Zhu
- School of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062, PR China.
| | - Yuan Kong
- Hefei National Laboratory for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics CAS Center for Excellence in Nanoscience and Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, PR China.
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6
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Zhang H, Zhang X, Xie C, Shi W, Yang P. Composite nanoarchitectonics with TiO 2 nanocrystals and superior thin Ti 3C 2T x nanosheets towards efficient NO removal. ENVIRONMENTAL RESEARCH 2023; 227:115793. [PMID: 37001850 DOI: 10.1016/j.envres.2023.115793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/14/2023] [Accepted: 03/28/2023] [Indexed: 05/08/2023]
Abstract
Accordion-like Ti3C2Tx MXene supplied a possibility to construct two-dimensional composites with novel performance. In this paper, few-layered Ti3C2Tx MXene was created via a chemical etching strategy. The oxidation in-situ using a powerful alkaline solution resulted successfully in TiO2 nanocrystals grown on Ti3C2Tx nanosheets. The alkaline treatment adjusted terminations of the Ti3C2Tx MXene and controlled the oxidation degree by changing temperature. The ratio of Ti3C2Tx and TiO2 was finally optimized. Because of Ti3C2Tx nanosheets with well conductivity and excellent light absorption as well as TiO2 nanocrystal arrays on Ti3C2Tx nanosheets with a high specific surface area and more active sites, TiO2/Ti3C2Tx composites revealed excellent photocatalystic activity, especially for NO removal. The improvement of separation and transfer efficiency of phootogenerated carriers is ascribed to the microstructure of TiO2/Ti3C2Tx composites. The composite sample synthesized at 75 °C revealed the best NO removal efficiency, in which 70% of NO was removed at a concentration of 600 ppb. This study offers a new thought for preparing high performance MXene-based photocatalysts.
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Affiliation(s)
- Hongyu Zhang
- School of Material Science and Engineering, University of Jinan, Jinan, 250022, PR China
| | - Xiao Zhang
- Faculty of Chemical Engineering and Technology, Cracow University of Technology, Krakow, Poland.
| | - Cong Xie
- School of Material Science and Engineering, University of Jinan, Jinan, 250022, PR China
| | - Wenbin Shi
- School of Material Science and Engineering, University of Jinan, Jinan, 250022, PR China
| | - Ping Yang
- School of Material Science and Engineering, University of Jinan, Jinan, 250022, PR China.
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7
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Hailili R, Reyimu X, Li Z, Lu X, Bahnemann DW. Tuning the Microstructures of ZnO To Enhance Photocatalytic NO Removal Performances. ACS APPLIED MATERIALS & INTERFACES 2023; 15:23185-23198. [PMID: 37129564 DOI: 10.1021/acsami.3c02286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Effective removal of kinetically inert dilute nitrogen oxide (NO, ppb) without NO2 emission is still a challenging topic in environmental pollution control. One effective approach to reducing the harm of NO is the construction of photocatalysts with diversified microstructures and atomic arrangements that could promote adsorption, activation, and complete removal of NO without yielding secondary pollution. Herein, microstructure regulations of ZnO photocatalysts were attempted by altering the reaction temperature and alkalinity in a unique ionic liquid-based solid-state synthesis and further investigated for the removal of dilute NO upon light irradiation. Microstructure observations indicated that as-tuned photocatalysts displayed unique nucleation, diverse morphologies (spherical nanoparticles, short and long nanorods), defect-related optical characteristics, and enhanced carrier separations. Such defect-related surface-interface aspects, especially Vo″-related defects of ZnO devoted them to the 4.16-fold enhanced NO removal and 2.76 magnitude order decreased NO2 yields, respectively. Improved NO removal and toxic product inhabitation in as-tuned ZnO was disclosed by mechanistic exploitations. It was revealed that regulated microstructures, defect-related charge carrier separation, and strengthened surface interactions were beneficial to active species production and molecular oxygen activation in ZnO, subsequently contributing to the improved NO removal and simultaneous avoidance of NO2 formation. This investigation shed light on the facile regulation of microstructures and the roles of surface chemistry in the oxidation of low concentration NO in the ppb level upon light illumination.
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Affiliation(s)
- Reshalaiti Hailili
- MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Beijing Key Laboratory of Heat Transfer and Energy Conversion, Beijing University of Technology, Beijing 100124, P. R. China
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstr. 3, 30167 Hannover, Germany
| | - Xiaokaiti Reyimu
- MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Beijing Key Laboratory of Heat Transfer and Energy Conversion, Beijing University of Technology, Beijing 100124, P. R. China
| | - Zelong Li
- MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Beijing Key Laboratory of Heat Transfer and Energy Conversion, Beijing University of Technology, Beijing 100124, P. R. China
| | - Xu Lu
- MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Beijing Key Laboratory of Heat Transfer and Energy Conversion, Beijing University of Technology, Beijing 100124, P. R. China
| | - Detlef W Bahnemann
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstr. 3, 30167 Hannover, Germany
- Laboratory "Photoactive Nanocomposite Materials", Saint Petersburg State University, Saint-Petersburg 198504, Russia
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Qi Z, Chen J, Zhou W, Li Y, Li X, Zhang S, Fan J, Lv K. Synergistic effects of holey nanosheet and sulfur-doping on the photocatalytic activity of carbon nitride towards NO removal. CHEMOSPHERE 2023; 316:137813. [PMID: 36642138 DOI: 10.1016/j.chemosphere.2023.137813] [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: 10/09/2022] [Revised: 12/28/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Photocatalysis provides a sustainable way for NOx elimination. However, efficient and safe photocatalytic removal of NOx remain a great challenge due to the limited light-harvesting ability and quick recombination of charge carriers. Herein, holey sulfur-doped g-C3N4 nanosheets (CNN-S) was reported by directly calcining a mixture of hydrolyzed dicyandiamide and thioacetamide. The specific surface area of the pristine g-C3N4 nanosheets (CNN-S0) is 3-4 times higher than bulk g-C3N4 (BCN), and the photocatalytic NO removal rate also increased from 17% (BCN) to 35% (CNN-S0). The effect of sulfur content on the photocatalytic performance was systematic studied, and CNN-S0.5 sample exhibits the highest NO removal rate (53%). The high photoreactivity of S-doped g-C3N4 nanosheets can be attributed to enhanced visible light absorption, increased specific surface area, and effective separation and transfer of photo-generated charges owing to the synergistic effect of the nanosheet structure and sulfur doping. In addition, density functional theory calculations show that the doping of S is also beneficial to the adsorption and activation of the reactants on CN.
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Affiliation(s)
- Zheng Qi
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Jinbao Chen
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Weichuang Zhou
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Yuhan Li
- Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China.
| | - Xiaofang Li
- College of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China
| | - Sushu Zhang
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Jiajie Fan
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Kangle Lv
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission & Ministry of Education, College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China.
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9
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Recent Advances in g-C3N4-Based Photocatalysts for NOx Removal. Catalysts 2023. [DOI: 10.3390/catal13010192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Nitrogen oxides (NOx) pollutants can cause a series of environmental issues, such as acid rain, ground-level ozone pollution, photochemical smog and global warming. Photocatalysis is supposed to be a promising technology to solve NOx pollution. Graphitic carbon nitride (g-C3N4) as a metal-free photocatalyst has attracted much attention since 2009. However, the pristine g-C3N4 suffers from poor response to visible light, rapid charge carrier recombination, small specific surface areas and few active sites, which results in deficient solar light efficiency and unsatisfactory photocatalytic performance. In this review, we summarize and highlight the recent advances in g-C3N4-based photocatalysts for photocatalytic NOx removal. Firstly, we attempt to elucidate the mechanism of the photocatalytic NOx removal process and introduce the metal-free g-C3N4 photocatalyst. Then, different kinds of modification strategies to enhance the photocatalytic NOx removal performance of g-C3N4-based photocatalysts are summarized and discussed in detail. Finally, we propose the significant challenges and future research topics on g-C3N4-based photocatalysts for photocatalytic NOx removal, which should be further investigated and resolved in this interesting research field.
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Porous Defective Bi/Bi3NbO7 Nanosheets for Efficient Photocatalytic NO Removal under Visible Light. Processes (Basel) 2022. [DOI: 10.3390/pr11010115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Since conventional techniques are ineffective for NO removal at low concentrations, photocatalysis has become attractive in this regard, recently. However, in practice, photocatalytic NO removal has drawbacks such as limited light absorption and the proclivity of producing toxic by-products. To address these issues, novel defective Bi/Bi3NbO7 structures with good porosity were fabricated by a solvothermal method and used for enhanced photocatalytic NO removal under visible light irradiation. The morphological and structural properties of the prepared materials were comprehensively analyzed. The optimal photocatalytic activity of pore-defective Bi/Bi3NbO7 for NO removal was 60.3%, when the molar ratios of urea and Bi(NO)3•5H2O to pristine Bi3NbO7 were 1:25 and 1:2, respectively, under the following operational conditions: NO concentration of 700 ppb, catalyst dosage of 50 mg and irradiation time of 14 min. The induced defects and the surface plasmon resonance (SPR) effect of Bi nanodots made remarkable contributions to improving the photocatalytic NO removal as well as inhibiting the toxic byproduct NO2. The photocatalytic NO removal pathway over the prepared photocatalysts was further mechanistically clarified taking advantage of EPR results and scavenging experiments. Considering the increased NO generation in the atmosphere, this work may provide novel insights for designing effective porous photocatalysts to treat gaseous toxic pollutants.
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