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Shaddad MN, Arunachalam P, Hezam MS, Aladeemy SA, Aljaafreh MJ, Abu Alrub S, Al-Mayouf AM. Enhanced Electrocatalytic Oxygen Reduction Reaction of TiO 2 Nanotubes by Combining Surface Oxygen Vacancy Engineering and Zr Doping. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:366. [PMID: 38392739 PMCID: PMC10892297 DOI: 10.3390/nano14040366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 02/24/2024]
Abstract
This work examines the cooperative effect between Zr doping and oxygen vacancy engineering in anodized TiO2 nanotubes (TNTs) for enhanced oxygen reduction reactions (ORRs). Zr dopant and annealing conditions significantly affected the electrocatalytic characteristics of grown TNTs. Zr doping results in Zr4+ substituted for Ti4+ species, which indirectly creates oxygen vacancy donors that enhance charge transfer kinetics and reduce carrier recombination in TNT bulk. Moreover, oxygen vacancies promote the creation of unsaturated Ti3+(Zr3+) sites at the surface, which also boosts the ORR interfacial process. Annealing at reductive atmospheres (e.g., H2, vacuum) resulted in a larger increase in oxygen vacancies, which greatly enhanced the ORR activity. In comparison to bare TNTs, Zr doping and vacuum treatment (Zr:TNT-Vac) significantly improved the conductivity and activity of ORRs in alkaline media. The finding also provides selective hydrogen peroxide production by the electrochemical reduction of oxygen.
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Affiliation(s)
- Maged N. Shaddad
- Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, P.O. Box 173, Al-Kharj 11942, Saudi Arabia
| | - Prabhakarn Arunachalam
- Electrochemical Sciences Research Chair (ESRC), Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Mahmoud S. Hezam
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
| | - Saba A. Aladeemy
- Department of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, P.O. Box 173, Al-Kharj 11942, Saudi Arabia
| | - Mamduh J. Aljaafreh
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
| | - Sharif Abu Alrub
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
| | - Abdullah M. Al-Mayouf
- Electrochemical Sciences Research Chair (ESRC), Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
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Barawi M, García-Tecedor M, Gomez-Mendoza M, Gorni G, Liras M, de la Peña O'Shea VA, Collado L. Light-Driven Nitrogen Fixation to Ammonia over Aqueous-Dispersed Mo-Doped TiO 2 Colloidal Nanocrystals. ACS APPLIED MATERIALS & INTERFACES 2023; 15:53382-53394. [PMID: 37950688 DOI: 10.1021/acsami.3c10396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2023]
Abstract
Photocatalytic nitrogen fixation to ammonia and nitrates holds great promise as a sustainable route powered by solar energy and fed with renewable energy resources (N2 and H2O). This technology is currently under deep investigation to overcome the limited efficiency of the process. The rational design of efficient and robust photocatalysts is crucial to boost the photocatalytic performance. Widely used bulk materials generally suffer from charge recombination due to poor interfacial charge transfer and difficult surface diffusion. To overcome this limitation, this work explores the use of aqueous-dispersed colloidal semiconductor nanocrystals (NCs) with precise morphological control, better carrier mobility, and stronger redox ability. Here, the TiO2 framework has been modified via aliovalent molybdenum doping, and resulting Mo-TiO2 NCs have been functionalized with charged terminating hydroxyl groups (OH-) for the simultaneous production of ammonia, nitrites, and nitrates via photocatalytic nitrogen reduction in water, which has not been previously found in the literature. Our results demonstrate the positive effect of Mo-doping and nanostructuration on the overall N2 fixation performance. Ammonia production rates are found to be dependent on the Mo-doping loading. 5Mo-TiO2 delivers the highest NH4+ yield rate (ca. 105.3 μmol g-1 L-1 h-1) with an outstanding 90% selectivity, which is almost four times higher than that obtained over bare TiO2. The wide range of advance characterization techniques used in this work reveals that Mo-doping enhances charge-transfer processes and carriers lifetime as a consequence of the creation of new intra band gap states in Mo-doped TiO2 NCs.
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Affiliation(s)
- Mariam Barawi
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
| | - Miguel García-Tecedor
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
| | - Miguel Gomez-Mendoza
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
| | - Giulio Gorni
- CLÆSS Beamline, CELLS-ALBA Synchrotron, carrer de la Llum, 2-26, Cerdanyola del Vallès, Barcelona 08290, Spain
- Laser Processing Group, Instituto de Óptica (CSIC), c/Serrano 121, Madrid 28006, Spain
| | - Marta Liras
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
| | - Víctor A de la Peña O'Shea
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
| | - Laura Collado
- Photoactivated Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra, 3, Móstoles, Madrid 28935, Spain
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Zhang J, Li Y, Liu C, Zhu C, shao C, Zhao Y. Photo-electrocatalytic degradation of tylosin by TiO2 nanotube modified photoelectrode: Synthesis, kinetics, and mechanism investigations. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Boosting the Photoelectrochemical Water Oxidation Performance of TiO2 Nanotubes by Surface Modification Using Silver Phosphate. Catalysts 2022. [DOI: 10.3390/catal12111440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Photoelectrocatalytic approaches are fascinating options for long-lasting energy storage through the transformation of solar energy into electrical energy or hydrogen fuel. Herein, we report a facile method of fabricating a composite electrode of well-aligned TiO2 nanotubes (TNTs) decorated with photodeposited silver phosphate (Ag3PO4) nanoparticles. Assessment of the optical, physiochemical and photoelectrochemical features demonstrated that the fabricated TNTs/Ag3PO4 films showed a substantially boosted photocurrent response of 0.74 mA/cm2, almost a 3-fold enrichment in comparison with the pure TNTs. Specifically, the applied bias photon-to-current efficiency of the fabricated TNTs/Ag3PO4 composite electrode was 2.4-fold superior to that of the pure TNTs electrode. In these TNTs/Ag3PO4 photoanodes, the introduction of Ag3PO4 over TNTs enhanced light absorption and improved charge transfer and surface conductivity. The developed process can be generally applied to designing and developing efficient contact interfaces between photoanodes and numerous cocatalysts.
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Activation effect of nickel phosphate co-catalysts on the photoelectrochemical water oxidation performance of TiO2 nanotubes. JOURNAL OF SAUDI CHEMICAL SOCIETY 2022. [DOI: 10.1016/j.jscs.2022.101484] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Chen J, Xiang F, Zhu M, Li J, Yang H, Che Y, Mao Z. Efficient Synthesis of α-FeOOH from Pickling Wastewater in Falling Film Tower and Its Kinetics. ACS OMEGA 2021; 6:8394-8402. [PMID: 33817500 PMCID: PMC8015130 DOI: 10.1021/acsomega.1c00125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
An efficient way to synthesize α-FeOOH from pickling wastewater in a falling film tower was proposed for the first time. This method overcomes the shortcomings of the traditional air oxidation method, and its production efficiency is increased by 16 times. The purity of α-FeOOH synthesized from pickling wastewater can reach 96.3%, and the iron recovery rate is greater than 90%. At the same time, we have systematically studied its kinetics in the falling film tower. The reaction rate constant k at different temperatures was also determined with the activation energy E a = 32.2497 kJ/mol and the pre-exponential A = 47.4132 s-1. In addition, based on the double-film theory, a corresponding macrokinetic model was established. Also, the Hatta number in the reaction system was obtained, which proved the excellent gas-liquid mass transfer performance in the falling film tower. This work provides a promising method for the efficient production of α-FeOOH and the recycling of pickling wastewater.
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