https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51644 Tue 12 Sep 2023 20:14:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40439 Tue 02 Aug 2022 10:30:44 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52445 4+/Ce³⁺ compositions. Using DFT calculations combined with Bader charge analysis, it is demonstrated that stoichiometric ceria registers a higher oxidase mimetic activity than oxygen-deficient ceria with a low Ce⁴⁺/Ce³⁺ ratio due to a higher charge transfer from a substrate, 3,3',5,5' tetramethylbenzidine (TMB), to the ceria surface. We also show that the fluoride ions can significantly increase the charge transfer from the TMB surface to ceria irrespective of the surface Ce⁴⁺/Ce³⁺ ratio. Using this knowledge, we first compare the fluoride sensing properties of nanoceria with high Ce⁴⁺ and mixed Ce⁴⁺/Ce³⁺ oxidation states and further demonstrate that the linear detection range of fluoride ions can be extended to 1-10 ppm for nanoceria with mixed oxidation states. Then, we also demonstrate an assay for fluoride assisted detection of glutathione, an antioxidant with elevated levels during cancer, using nanoceria with a high surface Ce⁴⁺/Ce³⁺ ratio. The addition of fluoride ions in this assay allows the detection of glutathione in the linear range of 2.5-50 ppm with a limit of detection (LOD) of 3.8 ppm. These studies not only underpin the role of the surface Ce⁴⁺/Ce³⁺ ratio in tuning the fluoride assisted boost in the oxidase mimetic activity of nanoceria but also its strategic application in designing better colourimetric assays.]]> Thu 12 Oct 2023 15:28:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21134 Sat 24 Mar 2018 07:53:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19734 P2₁∣n, and a further transition associated with antiferromagnetic ordering at ⁓8.5 K. The main structural changes, through the phase transition, are orientational ordering of the azetidium groups and associated changes in hydrogen bonding. In marked contrast to conventional improper ferroelastic oxide perovskites, the driving mechanism is associated with the X-point of the cubic Brillouin zone rather than being driven by R- and M-point octahedral tilting. The total ferroelastic shear strain of up to ⁓5% is substantially greater than found for typical oxide perovskites, and highlights the potential of the flexible framework to undergo large relaxations in response to local structural changes. Measurements of elastic and anelastic properties by resonant ultrasound spectroscopy show some of the characteristic features of ferroelastic materials. In particular, acoustic dissipation below the transition point can be understood in terms of mobility of twin walls under the influence of external stress with relaxation times on the order of ⁓10⁻⁷s. Elastic softening as the transition is approached from above is interpreted in terms of coupling between acoustic modes and dynamic local ordering of the azetidium groups. Subsequent stiffening with further temperature reduction is interpreted in terms of classical strain–order parameter coupling at an improper ferroelastic transition which is close to being tricritical. By way of contrast, there are no overt changes in elastic or anelastic properties near 9 K, implying that any coupling of the antiferromagnetic order parameter with strain is weak or negligible.]]> Sat 24 Mar 2018 07:53:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29667 Sat 24 Mar 2018 07:32:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26919 Sat 24 Mar 2018 07:23:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25110 Sat 24 Mar 2018 07:17:16 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46323 3N₄ (P-CN) for advanced photocatalytic applications. Phosphorus doping and structural coupling with CdSe QDs are shown to significantly extend visible-light response of g-C₃N₄ up to 700 nm. The optimized sample 4CdSe/P-CN demonstrates enhanced visible-light driven overall water splitting activities for H₂ and O₂ evolution i.e. 113 and 55.5 μmol.h⁻¹.g⁻¹, respectively, as well as very high photocatalytic CO₂ to CH₄ conversion efficiency (47 μmol.h⁻¹.g⁻¹). It also exhibit higher activity (78 %) for 2,4-dichlorophenol degradation as compared to pristine CN-sample. Combined photoluminescence, transient/single wavelength photocurrent, photoelectrochemical, and coumarin fluorescence spectroscopy demonstrate that 4CdSe/P-CN nanocomposite exhibit enhanced charge separation efficiency which is responsible for improved visible light catalytic activities. Our work thus provide a new strategy to design low-cost and sustainable photocatalysis with wide visible-light activity for practical overall water splitting and CO₂ reduction applications.]]> Mon 29 Jan 2024 17:44:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54762 Mon 11 Mar 2024 15:00:44 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48095 Fri 24 Feb 2023 15:23:53 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43387 Fri 16 Sep 2022 09:30:32 AEST ]]>