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The visible-light-driven photocatalytic reduction of Cr 6+ using BiVO 4: assessing the effect of Au deposition and the reaction parameters. ENVIRONMENTAL TECHNOLOGY 2024; 45:1013-1023. [PMID: 36222246 DOI: 10.1080/09593330.2022.2135461] [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: 07/19/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
In this work, fern-leaf-like BiVO4 was used to photocatalytically reduce Cr6+ in water. Nanosized BiVO4 displayed bandgap energy and specific surface area of 2.49 eV and 5.65 m2 g-1, respectively. Metallic Au nanoparticles were deposited on the BiVO4 to increase the photocatalytic performance. To optimize the reaction conditions, the sacrificial agents methanol, ethanol, formic acid, dimethyl sulfoxide, and KI were tested, while different catalyst dosages and Au loadings were assessed. The best sacrificial agent was formic acid, which was used at an optimal concentration of 0.01 mol L-1. The complete removal of Cr6+ was attained after 90 min of visible light irradiation using a catalyst dosage of 1.5 g L-1. Depositing metallic Au nanoparticles barely improved the photocatalytic performance, thus unmodified BiVO4 was used to remove Cr6+ in tap water. The matrix effect slowed the photocatalytic process, and the complete removal of Cr6+ was achieved in 120 min. Cr3+ and Cr6+ species were precipitated on the catalyst surface at the end of the photocatalytic process; still, BiVO4 displayed high stability after three reaction cycles.
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Influence of oxygen vacancies, surface composition, and crystallite size on the photoelectrochemical oxidation activity of C,N-codoped TiO 2 for cefadroxil abatement along with O 3. CHEMOSPHERE 2023; 342:140133. [PMID: 37704085 DOI: 10.1016/j.chemosphere.2023.140133] [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: 05/01/2023] [Revised: 08/20/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
This study aims the development of photoelectrodes to be incorporated in a photoelectrocatalytic ozonation (PECO) process for tertiary treatment of urban wastewaters, targeting the removal of contaminants of emerging concern (CEC). PECO tests were performed using urban wastewater after secondary treatment fortified with Cefadroxil (CFX, C16H17N3O5S), as target model CEC. Three Nitrogen and Carbon doped TiO2 (CN-TiO2) electrodes were synthesized by anodizing at 50, 70, and 90 V, and calcined. These materials were characterized by X-Ray diffraction and Rietveld refinement, Scanning Electron Microscopy, Diffuse Reflectance Spectroscopy, X-ray photoelectron spectroscopy, chronoamperometry, and electrochemical impedance spectroscopy, to correlate defects with photoactivity. All photoanodes considerably reduced their main bandgaps by the incorporation of C and N species, to enable absorption capacities in the UV region using a Xe lamp. The lowest oxygen vacancy content and largest crystallite size were found for CN-TiO2-70, favoring the reduction of bulk defects that could act as recombination of charge carriers. Therefore, oxygen vacancies affect more the TiO2 photoactivity compared to the crystallite size or the light absorption capacity, confirming that a lower content of vacancies in the material bulk and surface doping significantly influence the activity as detected by Rietveld refinement, DRS, and XPS. The electrochemical techniques confirm that the highest photocurrent was obtained for CN-TiO2-70, whence this photoanode was chosen to carry out the CFX degradation. A point defect model simulating Nyquist plot reveals that the photoactivity depends on the speed to diffuse oxygen vacancies through the TiO2 coating. All abatement processes were followed by high-performance liquid chromatography, and Total Organic Carbon (TOC). At neutral and alkaline conditions, CFX is eliminated to levels below the analytical detection limit after 90 min of treatment (TOC removals of 87 and 91%, respectively), indicating that the coupling between the CN-TiO2-70 photocatalyst and ozone is effective in eliminating the contaminant due to parallel routes forming •OH species. Lower CFX degradation observed at acidic pH (TOC removal of 70%) is assigned to the difficulty of oxidizing protonated CFX species.
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Ethylenediamine-assisted solvothermal synthesis of ZnS/ZnO photocatalytic heterojunction for high-efficiency hydrogen production. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27206-8. [PMID: 37119492 DOI: 10.1007/s11356-023-27206-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/20/2023] [Indexed: 06/19/2023]
Abstract
Organic-inorganic hybrid materials have emerged as a class of novel materials over the last two decades, as they combine functional organic components and inorganic building blocks into unique materials through various chemical or physical interactions. In the present work, the importance of the use of ethylenediamine in sulfided materials applied to photocatalytic processes in the H2 production is demonstrated. The ZnS/ZnO heterojunction was prepared by the solvothermal synthesis in the presence and absence of ethylenediamine. The photocatalytic behavior showed that the addition of ethylenediamine increases the photocatalytic efficiency up to eight times compared to the photocatalyst without the organic agent. The materials were characterized by X-ray diffraction, scanning electron microscopy, infrared and UV-visible spectroscopies of solids, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and photoelectrochemical characterization. The ethylenediamine plays a double role: to stabilize the cubic phase of zinc sulfide and to act as a promoter molecule of charge transfer on the surface of ZnS/ZnO/en heterojunction, slowing down the rate of recombination of the electron-hole pair, which is reflected in a decrease in the resistance to transfer of charge carriers, improving the H2 production rate until 1564 µmol h-1 g-1.
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Structural changes and photocatalytic aspects into anatase network after doping with cerium: comprehensive study via radial distribution functions, electron density maps and molecular hardness. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Effect of emulsification techniques on the distribution of components on the surface of microparticles obtained by spray drying. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2021.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Hydrous cobalt-iridium oxide two-dimensional nanoframes: insights into activity and stability of bimetallic acidic oxygen evolution electrocatalysts. NANOSCALE ADVANCES 2021; 3:1976-1996. [PMID: 36133093 PMCID: PMC9419543 DOI: 10.1039/d0na00912a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/04/2021] [Indexed: 06/02/2023]
Abstract
Acidic oxygen evolution reaction (OER) electrocatalysts that have high activity, extended durability, and lower costs are needed to further the development and wide-scale adoption of proton-exchange membrane electrolyzers. In this work, we report hydrous cobalt-iridium oxide two-dimensional (2D) nanoframes exhibit higher oxygen evolution activity and similar stability compared with commercial IrO2; however, the bimetallic Co-Ir catalyst undergoes a significantly different degradation process compared with the monometallic IrO2 catalyst. The bimetallic Co-Ir 2D nanoframes consist of interconnected Co-Ir alloy domains within an unsupported, carbon-free, porous nanostructure that allows three-dimensional molecular access to the catalytically active surface sites. After electrochemical conditioning within the OER potential range, the predominately bimetallic alloy surface transforms to an oxide/hydroxide surface. Oxygen evolution activities determined using a rotating disk electrode configuration show that the hydrous Co-Ir oxide nanoframes provide 17 times higher OER mass activity and 18 times higher specific activity compared to commercial IrO2. The higher OER activities of the hydrous Co-Ir nanoframes are attributed to the presence of highly active surface iridium hydroxide groups. The accelerated durability testing of IrO2 resulted in lowering of the specific activity and partial dissolution of Ir. In contrast, the durability testing of hydrous Co-Ir oxide nanoframes resulted in the combination of a higher Ir dissolution rate, an increase in the relative contribution of surface iridium hydroxide groups and an increase in specific activity. The understanding of the differences in degradation processes between bimetallic and monometallic catalysts furthers our ability to design high activity and stability acidic OER electrocatalysts.
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One-step synthesis and photocatalytic behavior for H2 production from water of ZnS/MoS2 composite material. Catal Today 2021. [DOI: 10.1016/j.cattod.2019.08.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Photocatalytic behavior for the phenol degradation of ZnAl layered double hydroxide functionalized with SDS. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 277:111399. [PMID: 33059324 DOI: 10.1016/j.jenvman.2020.111399] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 07/31/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Functionalized ZnAl layered double hydroxide based photocatalyst was obtained by the addition of sodium dodecyl sulfate (SDS) during the synthesis by the coprecipitation method, and further calcination at 400 °C. Bare and modified materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, IR, UV-Vis, EPR and XPS spectroscopies, SEM and HRTEM. The synthesized material was evaluated in the photodegradation of phenol in a 40 ppm aqueous solution (4.25 × 10-4 mol of phenol/L), under UV light irradiation. An increasing in the degradation of phenol from 62 to 95%, and from 62 to 82% in the mineralization of phenol was obtained using SDS functionalized ZnAl LDH, in comparison with the unmodified material. This increase could be attributed to the presence of sulfate radicals, confirmed by the EPR study.
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The induced effect of chemical and photo-assisted deposition of molybdenum sulfide on carbon towards the hydrogen evolution reaction. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sol–gel synthesis and characterization of calcium-deficient hydroxyapatite photocatalysts suitable for hydrogen production: influence of the drip rate in the photocatalytic activity. SN APPLIED SCIENCES 2019. [DOI: 10.1007/s42452-019-1465-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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12
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In situ reactivation of spent NiMoP/γ-Al2O3 catalyst for hydrodesulfurization of straight-run gas oil. Catal Today 2019. [DOI: 10.1016/j.cattod.2019.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Contribution to the coordination chemistry of transition metal nitroprussides: a cryo-XPS study. NEW J CHEM 2019. [DOI: 10.1039/c9nj00141g] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The XPS Fe 2p3/2 core-level spectra of sodium hexacyanoferrate(ii) and sodium nitroprusside.
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Changes in biooxidation mechanism and transient biofilm characteristics by As(V) during arsenopyrite colonization with Acidithiobacillus thiooxidans. J Ind Microbiol Biotechnol 2018; 45:669-680. [PMID: 29858724 DOI: 10.1007/s10295-018-2051-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/23/2018] [Indexed: 11/25/2022]
Abstract
Chemical and surface analyses are carried out using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM-EDS), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS) and extracellular surface protein quantification to thoroughly investigate the effect of supplementary As(V) during biooxidation of arsenopyrite by Acidithiobacillus thiooxidans. It is revealed that arsenic can enhance bacterial reactions during bioleaching, which can strongly influence its mobility. Biofilms occur as compact-flattened microcolonies, being progressively covered by a significant amount of secondary compounds (S n2- , S0, pyrite-like). Biooxidation mechanism is modified in the presence of supplementary As(V), as indicated by spectroscopic and microscopic studies. GDS confirms significant variations between abiotic control and biooxidized arsenopyrite in terms of surface reactivity and amount of secondary compounds with and without As(V) (i.e. 6 μm depth). CLSM and protein analyses indicate a rapid modification in biofilm from hydrophilic to hydrophobic character (i.e. 1-12 h), in spite of the decrease in extracellular surface proteins in the presence of supplementary As(V) (i.e. stressed biofilms).
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Methanol Electro-Oxidation on Pt–Carbon Vulcan Catalyst Modified with WOx Nanostructures: An Approach to the Reaction Sequence Using DEMS. Ind Eng Chem Res 2016. [DOI: 10.1021/acs.iecr.6b02420] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Versailles Project on Advanced Materials and Standards Interlaboratory Study on Measuring the Thickness and Chemistry of Nanoparticle Coatings Using XPS and LEIS. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:24070-24079. [PMID: 27818719 PMCID: PMC5093768 DOI: 10.1021/acs.jpcc.6b06713] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) inter-laboratory study on the measurement of the shell thickness and chemistry of nanoparticle coatings. Peptide-coated gold particles were supplied to laboratories in two forms: a colloidal suspension in pure water and; particles dried onto a silicon wafer. Participants prepared and analyzed these samples using either X-ray photoelectron spectroscopy (XPS) or low energy ion scattering (LEIS). Careful data analysis revealed some significant sources of discrepancy, particularly for XPS. Degradation during transportation, storage or sample preparation resulted in a variability in thickness of 53 %. The calculation method chosen by XPS participants contributed a variability of 67 %. However, variability of 12 % was achieved for the samples deposited using a single method and by choosing photoelectron peaks that were not adversely affected by instrumental transmission effects. The study identified a need for more consistency in instrumental transmission functions and relative sensitivity factors, since this contributed a variability of 33 %. The results from the LEIS participants were more consistent, with variability of less than 10 % in thickness and this is mostly due to a common method of data analysis. The calculation was performed using a model developed for uniform, flat films and some participants employed a correction factor to account for the sample geometry, which appears warranted based upon a simulation of LEIS data from one of the participants and comparison to the XPS results.
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Versailles Project on Advanced Materials and Standards Interlaboratory Study on Measuring the Thickness and Chemistry of Nanoparticle Coatings Using XPS and LEIS. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:24070-24079. [PMID: 27818719 DOI: 10.1021/acs.jpcc.6b09412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) inter-laboratory study on the measurement of the shell thickness and chemistry of nanoparticle coatings. Peptide-coated gold particles were supplied to laboratories in two forms: a colloidal suspension in pure water and; particles dried onto a silicon wafer. Participants prepared and analyzed these samples using either X-ray photoelectron spectroscopy (XPS) or low energy ion scattering (LEIS). Careful data analysis revealed some significant sources of discrepancy, particularly for XPS. Degradation during transportation, storage or sample preparation resulted in a variability in thickness of 53 %. The calculation method chosen by XPS participants contributed a variability of 67 %. However, variability of 12 % was achieved for the samples deposited using a single method and by choosing photoelectron peaks that were not adversely affected by instrumental transmission effects. The study identified a need for more consistency in instrumental transmission functions and relative sensitivity factors, since this contributed a variability of 33 %. The results from the LEIS participants were more consistent, with variability of less than 10 % in thickness and this is mostly due to a common method of data analysis. The calculation was performed using a model developed for uniform, flat films and some participants employed a correction factor to account for the sample geometry, which appears warranted based upon a simulation of LEIS data from one of the participants and comparison to the XPS results.
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Photodegradation of phenol using reconstructed Ce doped Zn/Al layered double hydroxides as photocatalysts. Catal Today 2016. [DOI: 10.1016/j.cattod.2016.01.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Enhancing the H2 evolution from water–methanol solution using Mn2+–Mn+3–Mn4+ redox species of Mn-doped TiO2 sol–gel photocatalysts. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.12.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Microstructural properties and distribution of components in microparticles obtained by spray-drying. J FOOD ENG 2015. [DOI: 10.1016/j.jfoodeng.2014.11.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Preparation and characterization of Sb2O5-doped Ti/RuO2-ZrO2 for dye decolorization by means of active chlorine. J Solid State Electrochem 2014. [DOI: 10.1007/s10008-014-2554-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Photocatalytic degradation of 2,4-dichlorophenol with MgAlTi mixed oxides catalysts obtained from layered double hydroxides. JOURNAL OF HAZARDOUS MATERIALS 2013; 263 Pt 1:67-72. [PMID: 24184126 DOI: 10.1016/j.jhazmat.2013.09.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 09/19/2013] [Accepted: 09/20/2013] [Indexed: 06/02/2023]
Abstract
MgAl and MgAlTi mixed oxides were obtained from the thermal treatment of LDH materials synthesized by the sol-gel method; these materials were characterized by N2 physisorption, XRD, UV-vis, XPS, EDS-SEM and TEM techniques. According to the results, Ti was incorporated in the LDH layer when content in the material was low. The MgAl and MgAlTi mixed oxides were evaluated in the photo-degradation of 2,4-dichlorophenol (2,4-DCP) in the presence of UV light. A superior efficiency in the photo-degradation of 2,4-DCP, in comparison with the Degussa P-25 TiO2 reference catalyst was observed, reaching a total decomposition of the 2,4-DCP molecule in less than 60 min. According to the results, Ti was incorporated in the LDH layer when the content in the material was low. The MgAl and MgAlTi mixed oxides were evaluated in the photo-degradation of 2,4-dichlorophenol (2,4-DCP) in the presence of UV light. A superior efficiency in the photo-degradation of 2,4-DCP with the MgAl and MgAlTi mixed oxides, in comparison with the Degussa P-25 TiO2 reference catalyst was observed, reaching a total decomposition of the 2,4-DCP molecule in less than 60 min.
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Effect of water and fluoride content on morphology and barrier layer properties of TiO2 nanotubes grown in ethylene glycol-based electrolytes. J Solid State Electrochem 2013. [DOI: 10.1007/s10008-013-2212-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Influence of bovine serum albumin in sulphuric acid aqueous solution on the corrosion and the passivation of an iron–chromium alloy. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2005.02.116] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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