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Detection of 4-nitrophenol in wastewater using microstructures of various morphologies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134564] [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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Efficient Oxidation of Cyclohexane over Bulk Nickel Oxide under Mild Conditions. Molecules 2022; 27:molecules27103145. [PMID: 35630625 PMCID: PMC9146248 DOI: 10.3390/molecules27103145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 11/16/2022] Open
Abstract
Nickel oxide powder was prepared by simple calcination of nickel nitrate hexahydrate at 500 °C for 5 h and used as a catalyst for the oxidation of cyclohexane to produce the cyclohexanone and cyclohexanol—KA oil. Molecular oxygen (O2), hydrogen peroxide (H2O2), t-butyl hydrogen peroxide (TBHP) and meta-chloroperoxybenzoic acid (m-CPBA) were evaluated as oxidizing agents under different conditions. m-CPBA exhibited higher catalytic activity compared to other oxidants. Using 1.5 equivalent of m-CPBA as an oxygen donor agent for 24 h at 70 °C, in acetonitrile as a solvent, NiO powder showed exceptional catalytic activity for the oxidation of cyclohexane to produce KA oil. Compared to different catalytic systems reported in the literature, for the first time, about 85% of cyclohexane was converted to products, with 99% KA oil selectivity, including around 87% and 13% selectivity toward cyclohexanone and cyclohexanol, respectively. The reusability of NiO catalyst was also investigated. During four successive cycles, the conversion of cyclohexane and the selectivity toward cyclohexanone were decreased progressively to 63% and 60%, respectively, while the selectivity toward cyclohexanol was increased gradually to 40%.
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Białas K, Moschou D, Marken F, Estrela P. Electrochemical sensors based on metal nanoparticles with biocatalytic activity. Mikrochim Acta 2022; 189:172. [PMID: 35364739 PMCID: PMC8975783 DOI: 10.1007/s00604-022-05252-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/26/2022] [Indexed: 01/06/2023]
Abstract
Biosensors have attracted a great deal of attention, as they allow for the translation of the standard laboratory-based methods into small, portable devices. The field of biosensors has been growing, introducing innovations into their design to improve their sensing characteristics and reduce sample volume and user intervention. Enzymes are commonly used for determination purposes providing a high selectivity and sensitivity; however, their poor shelf-life is a limiting factor. Researchers have been studying the possibility of substituting enzymes with other materials with an enzyme-like activity and improved long-term stability and suitability for point-of-care biosensors. Extra attention is paid to metal and metal oxide nanoparticles, which are essential components of numerous enzyme-less catalytic sensors. The bottleneck of utilising metal-containing nanoparticles in sensing devices is achieving high selectivity and sensitivity. This review demonstrates similarities and differences between numerous metal nanoparticle-based sensors described in the literature to pinpoint the crucial factors determining their catalytic performance. Unlike other reviews, sensors are categorised by the type of metal to study their catalytic activity dependency on the environmental conditions. The results are based on studies on nanoparticle properties to narrow the gap between fundamental and applied research. The analysis shows that the catalytic activity of nanozymes is strongly dependent on their intrinsic properties (e.g. composition, size, shape) and external conditions (e.g. pH, type of electrolyte, and its chemical composition). Understanding the mechanisms behind the metal catalytic activity and how it can be improved helps designing a nanozyme-based sensor with the performance matching those of an enzyme-based device.
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Affiliation(s)
- Katarzyna Białas
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio), University of Bath, Bath, BA2 7AY, UK.,Department of Electronic and Electrical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Despina Moschou
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio), University of Bath, Bath, BA2 7AY, UK.,Department of Electronic and Electrical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Frank Marken
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio), University of Bath, Bath, BA2 7AY, UK.,Department of Chemistry, University of Bath, Bath, BA2 7AY, UK
| | - Pedro Estrela
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio), University of Bath, Bath, BA2 7AY, UK. .,Department of Electronic and Electrical Engineering, University of Bath, Bath, BA2 7AY, UK.
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Facile synthesis of N-doped hollow carbon nanospheres wrapped with transition metal oxides nanostructures as non-precious catalysts for the electro-oxidation of hydrazine. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114437] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Electrochemical approach towards the controllable synthesis of nickel nanocones based on the screw dislocation. APPLIED NANOSCIENCE 2019. [DOI: 10.1007/s13204-019-01233-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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