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Gao X, Zhu M, Long Y, Zhang X, Min D. Heterogeneous reaction of NO 2 with hematite: The effects of UV irradiation, O 2 and relative humidity. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 314:124205. [PMID: 38569389 DOI: 10.1016/j.saa.2024.124205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/29/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024]
Abstract
Heterogeneous reactions on mineral dust surfaces are increasingly considered important in the removal of gaseous pollutants and the formation of secondary aerosols. Although the heterogeneous reaction of NO2 on the hematite surface has been investigated in many previous studies, little is known about the reaction of NO2 with hematite under ambient conditions. In this work, heterogeneous reactions of NO2 with hematite at 298 K were investigated via a coated-wall flow tube reactor and in situ diffuse reflectance Fourier transformed infrared spectroscopy (DRIFTS). The influence of UV illumination, relative humidity (RH) and O2 on the uptake coefficients and adsorption amount of NO2, as well as the nitrate formation on the hematite surface, has been analyzed comprehensively. UV irradiation shows a significant effect on the true uptake coefficient (γBET), which increases from 2.00 × 10-6 to 4.76 × 10-6 in the N2 stream and 1.32 × 10-6 to 4.07 × 10-6 in the air stream under dry conditions (∼0.3 % RH). RH (in the range of 0-67 %) exhibits an inhibitory effect on the adsorption of NO2 on the hematite surface because of the competition between NO2 and water molecules, that is, γBET and adsorption amount of NO2 decrease with an increase in RH under both the dark and light reaction conditions. Meanwhile, both the γBET and adsorption amount of NO2 on hematite decrease in the air stream compared to those in N2 conditions. In addition, the results from the DRIFTS experiments indicate that the presence of UV irradiation promotes the conversion of NO2 to nitrate and both the RH and O2 suppress the nitrate formation. From this research, the heterogeneous reactions between NO2 with mineral dust under ambient conditions will be better understood.
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Affiliation(s)
- Xiaoyan Gao
- Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, Huaiyin Institute of Technology, Huaian 223003, China; National and Local Joint Engineering Research Center for Mineral Salt Deep Utilization, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Menglong Zhu
- Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, Huaiyin Institute of Technology, Huaian 223003, China
| | - Yu Long
- Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, Huaiyin Institute of Technology, Huaian 223003, China
| | - Xiaojie Zhang
- Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, Huaiyin Institute of Technology, Huaian 223003, China; National and Local Joint Engineering Research Center for Mineral Salt Deep Utilization, Huaiyin Institute of Technology, Huaian 223003, China
| | - Dandan Min
- Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, Huaiyin Institute of Technology, Huaian 223003, China; National and Local Joint Engineering Research Center for Mineral Salt Deep Utilization, Huaiyin Institute of Technology, Huaian 223003, China
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2
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Defect-rich BN-supported Cu with superior dispersion for ethanol conversion to aldehyde and hydrogen. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(21)63891-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Liu T, Chan AWH, Abbatt JPD. Multiphase Oxidation of Sulfur Dioxide in Aerosol Particles: Implications for Sulfate Formation in Polluted Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4227-4242. [PMID: 33760581 DOI: 10.1021/acs.est.0c06496] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atmospheric oxidation of sulfur dioxide (SO2) forms sulfate-containing aerosol particles that impact air quality, climate, and human and ecosystem health. It is well-known that in-cloud oxidation of SO2 frequently dominates over gas-phase oxidation on regional and global scales. Multiphase oxidation involving aerosol particles, fog, and cloud droplets has been generally thought to scale with liquid water content (LWC) so multiphase oxidation would be negligible for aerosol particles due to their low aerosol LWC. However, recent field evidence, particularly from East Asia, shows that fast sulfate formation prevails in cloud-free environments that are characterized by high aerosol loadings. By assuming that the kinetics of cloud water chemistry prevails for aerosol particles, most atmospheric models do not capture this phenomenon. Therefore, the field of aerosol SO2 multiphase chemistry has blossomed in the past decade, with many oxidation processes proposed to bridge the difference between modeled and observed sulfate mass loadings. This review summarizes recent advances in the fundamental understanding of the aerosol multiphase oxidation of SO2, with a focus on environmental conditions that affect the oxidation rate, experimental challenges, mechanisms and kinetics results for individual reaction pathways, and future research directions. Compared to dilute cloud water conditions, this paper highlights the differences that arise at the molecular level with the extremely high solute strengths present in aerosol particles.
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Affiliation(s)
- Tengyu Liu
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Arthur W H Chan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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4
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He X, Zhang YH. Influence of relative humidity on SO 2 oxidation by O 3 and NO 2 on the surface of TiO 2 particles: Potential for formation of secondary sulfate aerosol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 219:121-128. [PMID: 31030039 DOI: 10.1016/j.saa.2019.04.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 04/14/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
The heterogeneous reactions of SO2/O3 and SO2/NO2 with TiO2 particles were studied as a function of relative humidities (RHs). An in situ microscopic Fourier transform infrared (micro-FTIR) spectrometer was used to monitor the reaction kinetics. Rapid conversion of SO2 to sulfate occurs on the surface of TiO2 particles in the presence of O3 or NO2, which is sensitive to RHs. For unreacted (fresh) particles, the uptake coefficients for SO2 in initial stage are both obviously enhanced over four times with the increasing RH from ~4% to ~85%. Moreover, the uptake coefficient in the system of SO2/O3 is about 40% higher than that of SO2/NO2 on TiO2 particles at the similar RH conditions. For TiO2 after exposure to SO2/O3 or SO2/NO2 (sulfated) particles, the uptake coefficients for SO2 in moisture absorption stage are all higher than that on fresh particles in initial stage at the similar RH, indicating rapid mixture gases adsorption with particle hygroscopic growth. The high production of the secondary sulfate for heterogeneous reaction of mixture gases on TiO2 surface from arid region to humid region provides new insights for better understanding the severe haze under the humid condition.
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Affiliation(s)
- Xiang He
- College of Resource and Environment Sciences, Xinjiang University, Urumqi 830046, PR China; Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, PR China
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, PR China.
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Du C, Kong L, Zhanzakova A, Tong S, Yang X, Wang L, Fu H, Cheng T, Chen J, Zhang S. Impact of adsorbed nitrate on the heterogeneous conversion of SO 2 on α-Fe 2O 3 in the absence and presence of simulated solar irradiation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:1393-1402. [PMID: 30308908 DOI: 10.1016/j.scitotenv.2018.08.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 06/08/2023]
Abstract
Adsorbed nitrate is ubiquitous in the atmosphere, and it can undergo photolysis to produce oxidizing active radicals. Nitrate photolysis may be coupled with the oxidation conversions of atmospheric gaseous pollutants. However, the processes involved remain poorly understood. In this study, the impact of adsorbed nitrate on the heterogeneous oxidation of SO2 on α-Fe2O3 was investigated in the absence and presence of simulated solar irradiation by using in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that for α-Fe2O3 particles with no adsorbed nitrate, the formation of adsorbed sulfate on humid particles is stronger than that on dry particles. Meanwhile, light can also promote the heterogeneous conversion of SO2 and the formation of sulfate on dry particles because α-Fe2O3 is a typical photocatalyst. However, the heterogeneous conversion of SO2 on humid α-Fe2O3 particles is somewhat suppressed under light, suggesting the occurrence of photoinduced reductive dissolution. For the heterogeneous conversion of SO2 on α-Fe2O3 particles with adsorbed nitrate, the formation of sulfate on humid particles is still higher than that on dry particles. For the dry α-Fe2O3 particles with adsorbed nitrate, light promotes the formation of adsorbed sulfate. For the humid α-Fe2O3 particles with adsorbed nitrate, the heterogeneous conversion of SO2 under light is stronger than that under no light, indicating that the photolysis of adsorbed nitrate is coupled with the oxidation of SO2 and the formation of sulfate. The consumption of adsorbed nitrate and the formation of adsorbed N2O4 are observed during the introduction of SO2. A possible mechanism for the impact of adsorbed nitrate on the heterogeneous conversion of SO2 on α-Fe2O3 particles is proposed, and atmospheric implications based on these results are discussed.
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Affiliation(s)
- Chengtian Du
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Lingdong Kong
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China; Shanghai Institute of Eco-Chongming (SIEC), No. 3663 Northern Zhongshan Road, Shanghai 200062, China.
| | - Assiya Zhanzakova
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Songying Tong
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Xin Yang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Lin Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Hongbo Fu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Tiantao Cheng
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China; Shanghai Institute of Eco-Chongming (SIEC), No. 3663 Northern Zhongshan Road, Shanghai 200062, China
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China; Shanghai Institute of Eco-Chongming (SIEC), No. 3663 Northern Zhongshan Road, Shanghai 200062, China.
| | - Shicheng Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
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6
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Wang T, Liu Y, Deng Y, Fu H, Zhang L, Chen J. The influence of temperature on the heterogeneous uptake of SO 2 on hematite particles. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 644:1493-1502. [PMID: 30743862 DOI: 10.1016/j.scitotenv.2018.07.046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 06/09/2023]
Abstract
Despite the increased awareness of heterogeneous reactions of SO2 on mineral particles, the knowledge of how temperature influences the product species and kinetic parameters remain a crucially important part in atmospheric research. Here, we reported the formation of sulfur-containing species on hematite particles under various temperature and humidity conditions by mean of in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC). High temperature is helpful in the ionization of H2SO3, making sulfite compounds occupy a great share among total products. The whole reaction could be divided into three stages according to the formation rate of hydroxyl groups. High temperature brings about more activated SO2 and then results in the increased uptake coefficients with increasing temperature in the initial reaction stage. On the contrary, moisture absorption on particles is inhibited by high temperature, leading to the decreased uptake coefficients with increasing temperature in the latter two stages. Observed enthalpy and entropy, as well as activation energy values for relevant reactions were calculated. Overall, the product specie and reaction rate vary with temperature and humidity conditions, as well as reaction stages. This work broadens the knowledge of heterogeneous reactions on mineral dust influenced by temperature, and consequently provides important opportunities for atmospheric model improvements.
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Affiliation(s)
- Tao Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China
| | - Yangyang Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China
| | - Yue Deng
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China
| | - Hongbo Fu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China
| | - Liwu Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China.
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, People's Republic of China
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Sihvonen SK, Murphy KA, Washton NM, Altaf MB, Mueller KT, Freedman MA. Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite. Z PHYS CHEM 2017. [DOI: 10.1515/zpch-2016-0958] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Mineral dust aerosol participates in heterogeneous chemistry in the atmosphere. In particular, the hydroxyl groups on the surface of aluminosilicate clay minerals are important for heterogeneous atmospheric processes. These functional groups may be altered by acidic processing during atmospheric transport. In this study, we exposed kaolinite (KGa-1b) and montmorillonite (STx-1b) to aqueous sulfuric acid and then rinsed the soluble reactants and products off in order to explore changes to functional groups on the mineral surface. To quantify the changes due to acid treatment of edge hydroxyl groups, we use 19F magic angle spinning nuclear magnetic resonance spectroscopy and a probe molecule, 3,3,3-trifluoropropyldimethylchlorosilane. We find that the edge hydroxyl groups (OH) increase in both number and density with acid treatment. Chemical reactions in the atmosphere may be impacted by the increase in OH at the mineral edge.
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Affiliation(s)
- Sarah K. Sihvonen
- Department of Chemistry , The Pennsylvania State University , University Park, PA 16802 , USA
| | - Kelly A. Murphy
- Department of Chemistry , The Pennsylvania State University , University Park, PA 16802 , USA
| | - Nancy M. Washton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, WA 99352 , USA
| | - Muhammad Bilal Altaf
- Department of Chemistry , The Pennsylvania State University , University Park, PA 16802 , USA
| | - Karl T. Mueller
- Physical and Computational Sciences Directorate , Pacific Northwest National Laboratory , Richland, WA 99352 , USA
| | - Miriam Arak Freedman
- Department of Chemistry , The Pennsylvania State University , University Park, PA 16802 , USA
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8
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Sun Z, Kong L, Ding X, Du C, Zhao X, Chen J, Fu H, Yang X, Cheng T. The effects of acetaldehyde, glyoxal and acetic acid on the heterogeneous reaction of nitrogen dioxide on gamma-alumina. Phys Chem Chem Phys 2016; 18:9367-76. [PMID: 26745767 DOI: 10.1039/c5cp05632b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heterogeneous reactions of nitrogen oxides on the surface of aluminium oxide result in the formation of adsorbed nitrite and nitrate. However, little is known about the effects of other species on these heterogeneous reactions and their products. In this study, diffuse reflectance infrared spectroscopy (DRIFTS) was used to analyze the process of the heterogeneous reaction of NO2 on the surface of aluminium oxide particles in the presence of pre-adsorbed organic species (acetaldehyde, glyoxal and acetic acid) at 298 K and reveal the influence of these organic species on the formation of adsorbed nitrite and nitrate. It was found that the pre-adsorption of organic species (acetaldehyde, glyoxal and acetic acid) on γ-Al2O3 could suppress the formation of nitrate to different extents. Under the same experimental conditions, the suppression of the formation of nitrate by the pre-adsorption of acetic acid is much stronger than that by pre-adsorption of acetaldehyde and glyoxal, indicating that the influence of acetic acid on the heterogeneous reaction of NO2 is different from that of acetaldehyde and glyoxal. Surface nitrite is formed and identified to be an intermediate product. For the heterogeneous reaction of NO2 on the surface of γ-Al2O3 with and without the pre-adsorption of acetaldehyde and glyoxal, it is firstly formed and then gradually disappears as the reaction proceeds, but for the reaction with the pre-adsorption of acetic acid, it is the final main product besides nitrate. This indicates that the pre-adsorption of acetic acid would promote the formation of nitrite, while the others would not change the trend of the formation of nitrite. The possible influence mechanisms of the pre-adsorption of acetaldehyde, glyoxal and acetic acid on the heterogeneous conversion of NO2 on γ-Al2O3 are proposed and atmospheric implications based on these results are discussed.
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Affiliation(s)
- Zhenyu Sun
- Shanghai Key Laboratory of Atmospheric Particle Pollution, Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China.
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Tang M, Cziczo DJ, Grassian VH. Interactions of Water with Mineral Dust Aerosol: Water Adsorption, Hygroscopicity, Cloud Condensation, and Ice Nucleation. Chem Rev 2016; 116:4205-59. [DOI: 10.1021/acs.chemrev.5b00529] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mingjin Tang
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Daniel J. Cziczo
- Department
of Earth, Atmospheric and Planetary Sciences and Civil and Environmental
Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Vicki H. Grassian
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
- Departments
of Chemistry and Biochemistry, Nanoengineering and Scripps Institution
of Oceanography, University of California San Diego, La Jolla, California 92093, United States
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Shimizu K, Tschulik K, Compton RG. Exploring the mineral-water interface: reduction and reaction kinetics of single hematite (α-Fe 2O 3) nanoparticles. Chem Sci 2015; 7:1408-1414. [PMID: 29910899 PMCID: PMC5975920 DOI: 10.1039/c5sc03678j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/17/2015] [Indexed: 12/18/2022] Open
Abstract
Here we show that particle impact chronoamperometry allows the quantitative electrochemical characterization of individual mineral nanoparticles with adequate proton concentrations. Through this approach, we extract the kinetics and thermodynamics of the reductive dissolution of single hematite (α-Fe2O3) nanoparticles.
In spite of their natural and technological importance, the intrinsic electrochemical properties of hematite (α-Fe2O3) nanoparticles are not well understood. In particular, particle agglomeration, the presence of surface impurities, and/or inadequate proton concentrations are major obstacles to uncover the fundamental redox activities of minerals in solution. These are particularly problematic when samples are characterized in common electrochemical analyses such as cyclic voltammetry in which nanoparticles are immobilized on a stationary electrode. In this work, the intrinsic reaction kinetics and thermodynamics of individual hematite nanoparticles are investigated by particle impact chronoamperometry. The particle radius derived from the integrated area of spikes recorded in a chronoamperogram is in excellent agreement with electron microscopy results, indicating that the method provides a quantitative analysis of the reduction of the nanoparticles to the ferrous ion. A key finding is that the suspended individual nanoparticles undergo electrochemical reduction at potentials much more positive than those immobilized on a stationary electrode. The critical importance of the solid/water interface on nanoparticle activity is further illustrated by a kinetic model. It is found that the first electron transfer process is the rate determining step of the reductive dissolution of hematite nanoparticles, while the overall process is strongly affected by the interfacial proton concentration. This article highlights the effects of the interfacial proton and ferrous ion concentrations on the reductive dissolution of hematite nanoparticles and provides a highly effective method that can be readily applied to study a wide range of other mineral nanoparticles.
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Affiliation(s)
- K Shimizu
- Department of Chemistry , Physical and Theoretical Chemistry Laboratory , Oxford University , South Parks Road , Oxford , OX1 3QZ , UK . ; ; Tel: +44 (0)1865 275 957
| | - K Tschulik
- Department of Chemistry , Physical and Theoretical Chemistry Laboratory , Oxford University , South Parks Road , Oxford , OX1 3QZ , UK . ; ; Tel: +44 (0)1865 275 957.,Nano-Electrochemistry - Center for Electrochemical Sciences , Faculty of Chemistry and Biochemistry , Ruhr-University Bochum , D-44780 Bochum , Germany
| | - R G Compton
- Department of Chemistry , Physical and Theoretical Chemistry Laboratory , Oxford University , South Parks Road , Oxford , OX1 3QZ , UK . ; ; Tel: +44 (0)1865 275 957
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