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Berardi S, Cristino V, Bignozzi CA, Grandi S, Caramori S. Hematite-based photoelectrochemical interfaces for solar fuel production. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.120862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Banbela HM, Alharbi LM, Al-Dahiri RH, Jaremko M, Abdel Salam M. Preparation, Characterization, and Electrochemical Performance of the Hematite/Oxidized Multi-Walled Carbon Nanotubes Nanocomposite. Molecules 2022; 27:molecules27092708. [PMID: 35566063 PMCID: PMC9102378 DOI: 10.3390/molecules27092708] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/10/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
In this research work, a hematite (α-Fe2O3) nanoparticle was prepared and then mixed with oxidized multi-walled carbon nanotubes (O-MWCNT) to form a stable suspension of an α-Fe2O3/O-MWCNTs nanocomposite. Different characterization techniques were used to explore the chemical and physical properties of the α-Fe2O3/O-MWCNTs nanocomposite, including XRD, FT-IR, UV-Vis, and SEM. The results revealed the successful formation of the α-Fe2O3 nanoparticles, and the oxidation of the MWCNT, as well as the formation of stable α-Fe2O3/O-MWCNTs nanocomposite. The electrochemical behaviour of the α-Fe2O3/O-MWCNTs nanocomposite was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), and the results revealed that modification of α-Fe2O3 nanoparticles with O-MWCNTs greatly enhanced electrochemical performance and capacitive behaviour, as well as cycling stability.
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Affiliation(s)
- Hadeel M. Banbela
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589, Saudi Arabia; (H.M.B.); (L.M.A.)
- Department of Chemistry, College of Science and Arts at Khulis, University of Jeddah, P.O. Box 355, Jeddah 21959, Saudi Arabia
| | - Laila M. Alharbi
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589, Saudi Arabia; (H.M.B.); (L.M.A.)
| | - Reema H. Al-Dahiri
- Department of Chemistry, College of Science, University of Jeddah, P.O. Box 34, Jeddah 21959, Saudi Arabia;
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI), Red Sea Research Center (RSRC), Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), P.O. Box 4700, Thuwal 23955-6900, Saudi Arabia;
| | - Mohamed Abdel Salam
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589, Saudi Arabia; (H.M.B.); (L.M.A.)
- Correspondence: ; Tel.: +966-541886660; Fax: +966-2-6952292
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Berardi S, Kopula Kesavan J, Amidani L, Meloni EM, Marelli M, Boscherini F, Caramori S, Pasquini L. Better Together: Ilmenite/Hematite Junctions for Photoelectrochemical Water Oxidation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:47435-47446. [PMID: 32986954 PMCID: PMC8014905 DOI: 10.1021/acsami.0c12275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Hematite (α-Fe2O3) is an earth-abundant indirect n-type semiconductor displaying a band gap of about 2.2 eV, useful for collecting a large fraction of visible photons, with frontier energy levels suitably aligned for carrying out the photoelectrochemical water oxidation reaction under basic conditions. The modification of hematite mesoporous thin-film photoanodes with Ti(IV), as well as their functionalization with an oxygen-evolving catalyst, leads to a 6-fold increase in photocurrent density with respect to the unmodified electrode. In order to provide a detailed understanding of this behavior, we report a study of Ti-containing phases within the mesoporous film structure. Using X-ray absorption fine structure and high-resolution transmission electron microscopy coupled with electron energy loss spectroscopy, we find that Ti(IV) ions are incorporated within ilmenite (FeTiO3) near-surface layers, thus modifying the semiconductor-electrolyte interface. To the best of our knowledge, this is the first time that an FeTiO3/α-Fe2O3 composite is used in a photoelectrochemical setup for water oxidation. In fact, previous studies of Ti(IV)-modified hematite photoanodes reported the formation of pseudobrookite (Fe2TiO5) at the surface. By means of transient absorption spectroscopy, transient photocurrent experiments, and electrochemical impedance spectroscopy, we show that the formation of the Fe2O3/FeTiO3 interface passivates deep traps at the surface and induces a large density of donor levels, resulting in a strong depletion field that separates electron and holes, favoring hole injection in the electrolyte. Our results provide the identification of a phase coexistence with enhanced photoelectrochemical performance, allowing for the rational design of new photoanodes with improved kinetics.
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Affiliation(s)
- Serena Berardi
- Department
of Chemical and Pharmaceutical Sciences, University of Ferrara, via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Jagadesh Kopula Kesavan
- Department
of Physics and Astronomy, Alma Mater Studiorum−Università
di Bologna, viale Carlo Berti Pichat 6/2, 40127 Bologna, Italy
| | - Lucia Amidani
- Helmholtz-Zentrum
Dresden-Rossendorf, c/o European Synchrotron
Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Elia Marek Meloni
- Department
of Chemical and Pharmaceutical Sciences, University of Ferrara, via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Marcello Marelli
- CNR-SCITEC, Istituto di Scienze e Tecnologie Chimiche “Giulio
Natta”, Via Gaudenzio Fantoli 16/15, 20138 Milano, Italy
| | - Federico Boscherini
- Department
of Physics and Astronomy, Alma Mater Studiorum−Università
di Bologna, viale Carlo Berti Pichat 6/2, 40127 Bologna, Italy
| | - Stefano Caramori
- Department
of Chemical and Pharmaceutical Sciences, University of Ferrara, via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Luca Pasquini
- Department
of Physics and Astronomy, Alma Mater Studiorum−Università
di Bologna, viale Carlo Berti Pichat 6/2, 40127 Bologna, Italy
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Orlandi M, Berardi S, Mazzi A, Caramori S, Boaretto R, Nart F, Bignozzi CA, Bazzanella N, Patel N, Miotello A. Rational Design Combining Morphology and Charge-Dynamic for Hematite/Nickel-Iron Oxide Thin-Layer Photoanodes: Insights into the Role of the Absorber/Catalyst Junction. ACS APPLIED MATERIALS & INTERFACES 2019; 11:48002-48012. [PMID: 31797662 DOI: 10.1021/acsami.9b19790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Water oxidation represents the anodic reaction in most of the photoelectrosynthetic setups for artificial photosynthesis developed so far. The efficiency of the overall process strongly depends on the joint exploitation of good absorber domains and interfaces with minimized recombination pathways. To this end, we report on the effective coupling of thin-layer hematite with amorphous porous nickel-iron oxide catalysts prepared via pulsed laser deposition. The rational design of such composite photoelectrodes leads to the formation of a functional adaptive junction, with enhanced photoanodic properties with respect to bare hematite. Electrochemical impedance spectroscopy has contributed to shed light on the mechanisms of photocurrent generation, confirming the reduction of recombination pathways as the main contributor to the improved performances of the functionalized photoelectrodes. Our results highlight the importance of the amorphous catalysts' morphology, as dense and electrolyte impermeable layers hinder the pivotal charge compensation processes at the interface. The direct comparison with all-iron and all-nickel catalytic counterparts further confirms that control over the kinetics of both hole transfer and charge recombination, enabled by the adaptive junction, is key for the optimal operation of this kind of semiconductor/catalyst interfaces.
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Affiliation(s)
- Michele Orlandi
- Department of Physics , University of Trento , Via Sommarive 14 , Povo , Trento I-38123 , Italy
| | - Serena Berardi
- Department of Chemical and Pharmaceutical Sciences , University of Ferrara , Via Fossato di Mortara 17-19 , Ferrara 44100 , Italy
| | - Alberto Mazzi
- Department of Physics , University of Trento , Via Sommarive 14 , Povo , Trento I-38123 , Italy
| | - Stefano Caramori
- Department of Chemical and Pharmaceutical Sciences , University of Ferrara , Via Fossato di Mortara 17-19 , Ferrara 44100 , Italy
| | - Rita Boaretto
- Department of Chemical and Pharmaceutical Sciences , University of Ferrara , Via Fossato di Mortara 17-19 , Ferrara 44100 , Italy
| | - Francesco Nart
- Department of Chemical and Pharmaceutical Sciences , University of Ferrara , Via Fossato di Mortara 17-19 , Ferrara 44100 , Italy
| | - Carlo A Bignozzi
- Department of Chemical and Pharmaceutical Sciences , University of Ferrara , Via Fossato di Mortara 17-19 , Ferrara 44100 , Italy
| | - Nicola Bazzanella
- Department of Physics , University of Trento , Via Sommarive 14 , Povo , Trento I-38123 , Italy
| | - Nainesh Patel
- Department of Physics , University of Mumbai , Vidyanagari, Santacruz (E) , Mumbai 400 098 , India
| | - Antonio Miotello
- Department of Physics , University of Trento , Via Sommarive 14 , Povo , Trento I-38123 , Italy
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Elucidation of the structural and charge separation properties of titanium-doped hematite films deposited by electrospray method for photoelectrochemical water oxidation. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.11.166] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Seriani N. Ab initio simulations of water splitting on hematite. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:463002. [PMID: 29057752 DOI: 10.1088/1361-648x/aa84d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In recent years, hematite has attracted great interest as a photocatalyst for water splitting, but many questions remain unanswered about the mechanisms and the main limiting factors. For this reason, density functional theory has been used to understand the optical, electronic and chemical properties of this material at an atomistic level. Bulk doping can be used to reduce the band gap, and to increase photoabsorption and charge mobility. Charge transport takes place through adiabatic polaron hopping. The stable (0 0 0 1) surface has a stoichiometric termination when exposed to oxygen, it becomes hydroxylated in water, and it has an oxygen-rich termination under illumination in a photoelectrochemical setup. On the oxygen-rich termination, surface states are present that might act as recombination centres for electrons and holes. On the contrary, on the hydroxylated termination surface states appear only on reaction intermediates. The intrinsic surface states disappear in the presence of an overlayer of gallium oxide. The reaction of water oxidation is assumed to proceed by four proton-coupled electron transfers and it is shown to involve a nucleophilic attack with the formation of an OOH group. Calculated overpotentials are in the range of 0.5-0.6 V. Open questions and future research directions are briefly discussed.
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Affiliation(s)
- Nicola Seriani
- The Abdus Salam ICTP, Strada Costiera 11, 34151 Trieste, Italy
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