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Li K, Yin Y, Diao P. Enhancing Photoelectrochemical Water Oxidation on WO 3 via Electrochromic Modulation: Universal Effects and Mechanistic Insights. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402474. [PMID: 38822710 DOI: 10.1002/smll.202402474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/19/2024] [Indexed: 06/03/2024]
Abstract
Although WO3 exhibits both electrochromic and photoelectrochemical (PEC) properties, there is no research conducted to investigate the correlation between them. The study herein reports the electrochromic enhancement of PEC activity on WO3. The electrochromic WO3 (e-WO3) exhibits a significantly enhanced activity for PEC water oxidation compared to raw WO3 (r-WO3), with a limiting photocurrent density three times that of r-WO3. The electrochromic enhancement of PEC activity is universal and independent of the type of cations inserted during electrochromism. Decoloring reduces the PEC activity but a simple re-coloring restores the activity to its maximum value. Electrochromism induces large amounts of oxygen vacancies and surface states, the former improving the electron density of WO3 and the latter facilitating the hole transfer across e-WO3/electrolyte interface. It is proved that the electrochromic enhancement effect is due to the significantly improved electron-hole separation efficiency and the charge transfer efficiency across the WO3/electrolyte interface.
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Affiliation(s)
- Kangqiang Li
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Yefeng Yin
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Peng Diao
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
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Nomellini C, Polo A, Grigioni I, Marra G, Dozzi MV, Selli E. Ni(II)-doped CuWO 4 photoanodes with enhanced photoelectrocatalytic activity. Photochem Photobiol Sci 2023:10.1007/s43630-023-00484-4. [PMID: 37831332 DOI: 10.1007/s43630-023-00484-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Abstract
CuWO4 has emerged in the last years as a ternary metal oxide material for photoanodes application in photoelectrochemical cells, thanks to its relatively narrow band gap, high stability and selectivity toward the oxygen evolution reaction, though largely limited by its poor charge separation efficiency. Aiming at overcoming this limitation, we investigate here the effects that Cu(II) ion substitution has on the photoelectrocatalytic (PEC) performance of copper tungstate. Optically transparent CuWO4 thin-film photoanodes, prepared via spin coating and containing different amounts of Ni(II) ions, were fully characterized via UV-Vis spectroscopy, XRD and SEM analyses, and their PEC performance was tested via linear sweep voltammetry, incident photon to current efficiency and internal quantum efficiency analyses. From tests performed in the presence of a hole scavenger-containing electrolyte, the charge injection and separation efficiencies of the electrodes were also calculated. Pure-phase crystalline and/or heterojunction materials were obtained with higher PEC performance compared to pure CuWO4, mainly due to a significantly enhanced charge separation efficiency in the bulk of the material.
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Affiliation(s)
- Chiara Nomellini
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milan, Italy
| | - Annalisa Polo
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milan, Italy
| | - Ivan Grigioni
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milan, Italy
| | - Gianluigi Marra
- ENI S.p.A. Novara Laboratories (NOLAB), Renewable New Energies and Material Science Research Center (DE-R&D), Via G. Fauser 4, 28100, Novara, Italy
| | - Maria Vittoria Dozzi
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milan, Italy
| | - Elena Selli
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milan, Italy.
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Grigioni I, Polo A, Nomellini C, Vigni L, Poma A, Dozzi MV, Selli E. Nature of Charge Carrier Recombination in CuWO 4 Photoanodes for Photoelectrochemical Water Splitting. ACS APPLIED ENERGY MATERIALS 2023; 6:10020-10029. [PMID: 37830012 PMCID: PMC10565723 DOI: 10.1021/acsaem.3c01608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/01/2023] [Indexed: 10/14/2023]
Abstract
CuWO4 is a ternary semiconductor oxide with excellent visible light harvesting properties up to 550 nm and stability at high pH values, which make it a suitable material to build photoanodes for solar light conversion to hydrogen via water splitting. In this work, we studied the photoelectrochemical (PEC) performance of transparent CuWO4 electrodes with tunable light absorption and thickness, aiming at identifying the intrinsic bottlenecks of photogenerated charge carriers in this semiconductor. We found that electrodes with optimal CuWO4 thickness exhibit visible light activity due to the absorption of long-wavelength photons and a balanced electron and hole extraction from the oxide. The PEC performance of CuWO4 is light-intensity-dependent, with charge recombination increasing with light intensity and most photogenerated charge carriers recombining in bulk sites, as demonstrated by PEC tests performed in the presence of sacrificial agents or cocatalysts. The best-performing 580 nm thick CuWO4 electrode delivers a photocurrent of 0.37 mA cm-2 at 1.23 VSHE, with a 7% absorbed photon to current efficiency over the CuWO4 absorption spectrum.
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Affiliation(s)
- Ivan Grigioni
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Annalisa Polo
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Chiara Nomellini
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Laura Vigni
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Alessandro Poma
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Maria Vittoria Dozzi
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Elena Selli
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy
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Basu SS, Dhar D, Sengupta S, Basu JK. Controlled synthesis of Gd2MoO6 nanoflakes for enhanced charge kinetics in electrocatalytic oxygen evolution. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
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Chen L, Li W, Qiu W, He G, Wang K, Liu Y, Wu Q, Li J. Oriented CuWO 4 Films for Improved Photoelectrochemical Water Splitting. ACS APPLIED MATERIALS & INTERFACES 2022; 14:47737-47746. [PMID: 36228181 DOI: 10.1021/acsami.2c13002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Hydrogen generation through photoelectrochemical (PEC) technology is one of the most appropriate ways for delivering sustainable fuel. Simultaneously, anisotropic properties will be exhibited by the materials with low crystal symmetry, allowing the tuning of the PEC properties by controlling the crystallographic orientation and exposed facets. Therefore, we synthesized copper tungstate films (CuWO4) with highly exposed (100) crystal facets by regulating anions in the precursor solution. According to experimental characterization and density functional theory calculations, the CuWO4 film with a high exposure ratio of the (100) crystal facet has promoted charge transport with trap-free mode and reduced recombination of electrons and holes. Meanwhile, the oxygen evolution reaction is promoted on the (100) facet because of the relatively low energy barrier. Compared to the CuWO4 with other mixed exposure facets, CuWO4 with a highly exposed (100) facet presents a twofold current density (0.38 mA/cm2) and one-fifteenth electron transit time (0.698 ms) and also has great stability (more than 6 h). These results provide an easy way to enhance the PEC performance by modulating the exposure facets of the film electrode.
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Affiliation(s)
- Long Chen
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
| | - Wenzhang Li
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
- Hunan Provincial Key Laboratory of Powder Supply, Central South University, Changsha410083, China
| | - Weixin Qiu
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
| | - Gaoshuang He
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
| | - Keke Wang
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
| | - Yang Liu
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
| | - Qing Wu
- Information and Network Center, Central South University, Changsha410083, China
| | - Jie Li
- School of Chemistry and Chemical Engineering, Central South University, Changsha410083, China
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Liu Y, Chen L, Zhu X, Qiu H, Wang K, Li W, Cao S, Zhang T, Cai Y, Wu Q, Li J. Effects of operating temperature on photoelectrochemical performance of CuWO4 film photoanode. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Boosting the Activity and Stability of Copper Tungsten Nanoflakes toward Solar Water Oxidation by Iridium-Cobalt Phosphates Modification. Catalysts 2020. [DOI: 10.3390/catal10080913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Severe interfacial electron–hole recombination greatly limits the performance of CuWO4 photoanode towards the photoelectrochemical (PEC) oxygen evolution reaction (OER). Surface modification with an OER cocatalyst can reduce electron–hole recombination and thus improve the PEC OER performance of CuWO4. Herein, we coupled CuWO4 nanoflakes (NFs) with Iridium–cobalt phosphates (IrCo-Pi) and greatly improved the photoactivity of CuWO4. The optimized photocurrent density for CuWO4/IrCo-Pi at 1.23 V vs. reversible hydrogen electrode (RHE) rose to 0.54 mA∙cm−2, a ca. 70% increase over that of bare CuWO4 (0.32 mA∙cm−2). Such improved photoactivity was attributed to the enhanced hole collection efficiency, which resulted from the reduced charge-transfer resistance via IrCo-Pi modification. Moreover, the as-deposited IrCo-Pi layer well coated the inner CuWO4 NFs and effectively prevented the photoinduced corrosion of CuWO4 in neutral potassium phosphate (KPi) buffer solution, eventually leading to a superior stability over the bare CuWO4. The facile preparation of IrCo-Pi and its great improvement in the photoactivity make it possible to design an efficient CuWO4/cocatalyst system towards PEC water oxidation.
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