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Morgan DJ, Uthayasekaran S. Revisiting Degradation in the XPS Analysis of Polymers. SURF INTERFACE ANAL 2022. [DOI: 10.1002/sia.7151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- David J. Morgan
- School of Chemistry Cardiff UK
- HarwellXPS – EPSRC National Facility for Photoelectron spectroscopy, Research Complex at Harwell Didcot UK
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Laurans M, Wells JAL, Ott S. Immobilising molecular Ru complexes on a protective ultrathin oxide layer of p-Si electrodes towards photoelectrochemical CO 2 reduction. Dalton Trans 2021; 50:10482-10492. [PMID: 34259300 DOI: 10.1039/d1dt01331a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Photoelectrochemical CO2 reduction is a promising approach for renewable fuel generation and to reduce greenhouse gas emissions. Owing to their synthetic tunability, molecular catalysts for the CO2 reduction reaction can give rise to high product selectivity. In this context, a RuII complex [Ru(HO-tpy)(6-mbpy)(NCCH3)]2+ (HO-tpy = 4'-hydroxy-2,2':6',2''-terpyridine; 6-mbpy = 6-methyl-2,2'-bipyridine) was immobilised on a thin SiOx layer of a p-Si electrode that was decorated with a bromide-terminated molecular layer. Following the characterisation of the assembled photocathodes by X-ray photoelectron spectroscopy and ellipsometry, PEC experiments demonstrate electron transfer from the p-Si to the Ru complex through the native oxide layer under illumination and a cathodic bias. A state-of-the-art photovoltage of 570 mV was determined by comparison with an analogous n-type Si assembly. While the photovoltage of the modified photocathode is promising for future photoelectrochemical CO2 reduction and the p-Si/SiOx junction seems to be unchanged during the PEC experiments, a fast desorption of the molecular Ru complex was observed. An in-depth investigation of the cathode degradation by comparison with reference materials highlights the role of the hydroxyl functionality of the Ru complex to ensure its grafting on the substrate. In contrast, no essential role for the bromide function on the Si substrate designed to engage with the hydroxyl group of the Ru complex in an SN2-type reaction could be established.
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Affiliation(s)
- Maxime Laurans
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden.
| | - Jordann A L Wells
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden.
| | - Sascha Ott
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden.
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Charlton JJ, Jones NC, Wallace RA, Smithwick RW, Bradshaw JA, Kravchenko II, Lavrik NV, Sepaniak MJ. Nanopillar Based Enhanced-Fluorescence Detection of Surface-Immobilized Beryllium. Anal Chem 2015; 87:6814-21. [PMID: 26041094 DOI: 10.1021/acs.analchem.5b01035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unique properties associated with beryllium metal ensures the continued use in many industries despite the documented health and environmental risks. While engineered safeguards and personal protective equipment can reduce risks associated with working with the metal, it has been mandated by the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) that the workplace air and surfaces must be monitored for toxic levels. While many methods have been developed to monitor levels down to the low μg/m(3), the complexity and expense of these methods have driven the investigation into alternate methodologies. Herein, we use a combination of the previously developed fluorescence Be(II) ion detection reagent, 10-hydroxybenzo[h]quinoline (HBQ), with an optical field enhanced silicon nanopillar array, creating a new surface immobilized (si-HBQ) platform. The si-HBQ platform allows the positive control of the reagent for demonstrated reusability and a pillar diameter based tunable enhancement. Furthermore, native silicon nanopillars are overcoated with thin layers of porous silicon oxide to develop an analytical platform capable of a 0.0006 μg/L limit of detection (LOD) using sub-μL sample volumes. Additionally, we demonstrate a method to multiplex the introduction of the sample to the platform, with minimal 5.2% relative standard deviation (RSD) at 0.1 μg/L, to accommodate the potentially large number of samples needed to maintain industrial compliance. The minimal sample and reagent volumes and lack of complex and highly specific instrumentation, as well as positive control and reusability of traditionally consumable reagents, create a platform that is accessible and economically advantageous.
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Affiliation(s)
- Jennifer J Charlton
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.,‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - Natalie C Jones
- ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.,∥Northern Arizona University, College of Engineering, Forestry, and Natural Sciences, Flagstaff, Arizona 86011, United States
| | - Ryan A Wallace
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States
| | - Robert W Smithwick
- ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - James A Bradshaw
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.,‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - Ivan I Kravchenko
- §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Nickolay V Lavrik
- §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Michael J Sepaniak
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States
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