| 1. |
- Bericat Vadell, Robert, et al.
(author)
-
Single-electron transfer reactions on surface-modified gold plasmons
- 2023
-
In: Materials Today Chemistry. - : Elsevier. - 2468-5194. ; 34
-
Journal article (peer-reviewed)abstract
- Photoredox catalysis's relevance in organic synthesis research and innovation will increase in the coming decades. However, the processes rely almost exclusively on expensive noble metal complexes, most notably iridium complexes, to absorb light and transfer a single charge to a substrate or a catalyst to initiate cascade transformations. Light-triggered plasmon resonances generate a non-Fermi-Dirac energy distribution with many hot carriers that decay in similar to 1 ps. Their ultrafast relaxation makes performing single electron transfer (SET) transformations challenging. Herein, a novel photosystem is proposed based on surface-modified gold nanoparticles (aka plasmon "molecularization"), which improved charge separation and, more importantly, enabled SET reactions, expanding the portfolio of photocatalysts available for photoredox catalysis. The photosystem was made into an electrode, permitting its use in photoelectrochemical arrangements that leverage electro- and photo-chemical approaches' benefits and chemical engineering solutions, helping the synthetic chemistry efforts towards greener synthesis and synthesis of more complex structures on a scale.
|
|
| 2. |
- Dey, Ananta, et al.
(author)
-
Exploiting hot electrons from a plasmon nanohybrid system for the photoelectroreduction of CO2
- 2024
-
In: Communications Chemistry. - : Springer Nature. - 2399-3669. ; 7:1
-
Journal article (peer-reviewed)abstract
- Plasmonic materials convert light into hot carriers and heat to mediate catalytic transformation. The participation of hot carriers (photocatalysis) remains a subject of vigorous debate, often argued on the basis that carriers have ultrashort lifetime incompatible with drive photochemical processes. This study utilises plasmon hot electrons directly in the photoelectrocatalytic reduction of CO2 to CO via a Ppasmonic nanohybrid. Through the deliberate construction of a plasmonic nanohybrid system comprising NiO/Au/ReI(phen-NH2)(CO)3Cl (phen-NH2 = 1,10-Phenanthrolin-5-amine) that is unstable above 580 K; it was possible to demonstrate hot electrons are the main culprit in CO2 reduction. The engagement of hot electrons in the catalytic process is derived from many approaches that cover the processes in real-time, from ultrafast charge generation and separation to catalysis occurring on the minute scale. Unbiased in situ FTIR spectroscopy confirmed the stepwise reduction of the catalytic system. This, coupled with the low thermal stability of the ReI(phen-NH2)(CO)3Cl complex, explicitly establishes plasmonic hot carriers as the primary contributors to the process. Therefore, mediating catalytic reactions by plasmon hot carriers is feasible and holds promise for further exploration. Plasmonic nanohybrid systems can leverage plasmon’s unique photophysics and capabilities because they expedite the carrier’s lifetime.
|
|
| 3. |
- Fritze, Stefan, et al.
(author)
-
Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films
- 2024
-
In: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 477
-
Journal article (peer-reviewed)abstract
- The combination of strength and toughness is a major driving force for alloy design of protective coatings, and nanocrystalline tungsten (W)-alloys have shown to be promising candidates for combining strength and toughness. Here we investigate the elemental distribution and the fracture toughness of carbon (C) alloyed W thin films prepared by non-reactive magnetron sputtering. W:C films with up to ~4 at.% C crystallize in a body-centered-cubic structure with a strong 〈hh0〉texture, and no additional carbide phases are observed in the diffraction pattern. Atom probe tomography and X-ray photoelectron spectroscopy confirmed the formation of such a supersaturated solid solution. The pure W film has a hardness ~13 GPa and the W:C films exhibit a peak hardness of ~24 GPa. In-situ micromechanical cantilever bending tests show that the fracture toughness decreases from ~4.5 MPa·m1/2 for the W film to ~3.1 MPa·m1/2 for W:C films. The results show that C can significantly enhance the hardness of W thin films while retaining a high fracture toughness.
|
|
| 4. |
- Gopakumar, Geethanjali, 1992-, et al.
(author)
-
X-ray Induced Fragmentation of Protonated Cystine
- 2022
-
In: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 126:9, s. 1496-1503
-
Journal article (peer-reviewed)abstract
- We demonstrate site-specific X-ray induced fragmentation across the sulfur L-edge of protonated cystine, the dimer of the amino acid cysteine. Ion yield NEXAFS were performed in the gas phase using electrospray ionization (ESI) in combination with an ion trap. The interpretation of the sulfur L-edge NEXAFS spectrum is supported by Restricted Open-Shell Configuration Interaction (ROCIS) calculations. The fragmentation pathway of triply charged cystine ions was modeled by Molecular Dynamics (MD) simulations. We have deduced a possible pathway of fragmentation upon excitation and ionization of S 2p electrons. The disulfide bridge breaks for resonant excitation at lower photon energies but remains intact upon higher energy resonant excitation and upon ionization of S 2p. The larger fragments initially formed subsequently break into smaller fragments.
|
|
| 5. |
- Kalha, Curran, et al.
(author)
-
Hard x-ray photoelectron spectroscopy : a snapshot of the state-of-the-art in 2020
- 2021
-
In: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 33:23
-
Research review (peer-reviewed)abstract
- Hard x-ray photoelectron spectroscopy (HAXPES) is establishing itself as an essential technique for the characterisation of materials. The number of specialised photoelectron spectroscopy techniques making use of hard x-rays is steadily increasing and ever more complex experimental designs enable truly transformative insights into the chemical, electronic, magnetic, and structural nature of materials. This paper begins with a short historic perspective of HAXPES and spans from developments in the early days of photoelectron spectroscopy to provide an understanding of the origin and initial development of the technique to state-of-the-art instrumentation and experimental capabilities. The main motivation for and focus of this paper is to provide a picture of the technique in 2020, including a detailed overview of available experimental systems worldwide and insights into a range of specific measurement modi and approaches. We also aim to provide a glimpse into the future of the technique including possible developments and opportunities.
|
|
| 6. |
- Villamayor, Michelle Marie S., et al.
(author)
-
Wafer-sized WS2 monolayer deposition by sputtering
- 2022
-
In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 14:17, s. 6331-6338
-
Journal article (peer-reviewed)abstract
- We demonstrate that tungsten disulphide (WS2) with thicknesses ranging from monolayer (ML) to several monolayers can be grown on SiO2/Si, Si, and Al2O3 by pulsed direct current-sputtering. The presence of high quality monolayer and multilayered WS2 on the substrates is confirmed by Raman spectroscopy since the peak separations between the A(1g)-E-2g and A(1g)-2LA vibration modes exhibit a gradual increase depending on the number of layers. X-ray diffraction confirms a textured (001) growth of WS2 films. The surface roughness measured with atomic force microscopy is between 1.5 and 3 angstrom for the ML films. The chemical composition WSx (x = 2.03 +/- 0.05) was determined from X-ray Photoelectron Spectroscopy. Transmission electron microscopy was performed on a multilayer film to show the 2D layered structure. A unique method for growing 2D layers directly by sputtering opens up the way for designing 2D materials and batch production of high-uniformity and high-quality (stochiometric, large grain sizes, flatness) WS2 films, which will advance their practical applications in various fields.
|
|
| 7. |
- Almdalal, Tarik, et al.
(author)
-
Predictive characteristics for disease recurrence and overall survival in non-metastatic clinical T1 renal cell carcinoma : results from the National Swedish Kidney Cancer Register
- 2023
-
In: Scandinavian journal of urology. - : Taylor & Francis. - 2168-1805 .- 2168-1813. ; 57:1-6, s. 67-74
-
Journal article (peer-reviewed)abstract
- ObjectivePatients with clinical T1 renal cell carcinoma (cT1RCC) have risks for recurrence and reduced overall survival despite being in the best prognostic group. This study aimed to evaluate the association of different treatments on disease recurrence and overall survival using clinical and pathological characteristics in a nation-wide cT1RCC cohort.Materials and methodsA total of 4,965 patients, registered in the National Swedish Kidney Cancer Register (NSKCR) between 2005 and 2014, with ≥ 5-years follow-up were identified: 3,040 males and 1,925 females, mean age 65 years. Times to recurrence and overall survival were analyzed with Kaplan-Meier curves, log-rank test, and Cox regression models.ResultsAge, TNM-stage, tumor size, RCC-type, and performed treatment were all associated with disease recurrence. Patients selected for ablative treatments had increased risk for recurrent disease: hazard ratio (HR) = 3.79 [95% confidence interval (CI) = 2.69–5.32]. In multivariate analyses, age, gender, tumor size, RCC-type, N-stage, recurrence and performed treatment were all independently associated with overall survival. Patients with chRCC had a 41% better overall survival (HR = 0.59, 95% CI = 0.44–0.78; p < 0.001) than ccRCC. Patients treated with partial nephrectomy (PN) had an 18% better overall survival (HR = 0.83, 95% CI = 0.71–0.95, p < 0.001) than patients treated with radical nephrectomy.ConclusionsAge, gender, T-stage, tumor size, RCC type and treatment modality are all associated with risk of recurrence. Furthermore, age, male gender, tumor size, N-stage and recurrence are associated with reduced overall survival. Patients with chRCC, compared with ccRCC and pRCC patients, and PN compared with RN treated patients, had an advantageous overall survival, indicating a possible survival advantage of nephron sparing treatment.
|
|
| 8. |
|
|
| 9. |
- Barone, Giovanni D., et al.
(author)
-
Recent developments in the production and utilization of photosynthetic microorganisms for food applications
- 2023
-
In: Heliyon. - : Elsevier. - 2405-8440. ; 9:4
-
Research review (peer-reviewed)abstract
- The growing use of photosynthetic microorganisms for food and food-related applications is driving related biotechnology research forward. Increasing consumer acceptance, high sustain-ability, demand of eco-friendly sources for food, and considerable global economic concern are among the main factors to enhance the focus on the novel foods. In the cases of not toxic strains, photosynthetic microorganisms not only provide a source of sustainable nutrients but are also potentially healthy. Several published studies showed that microalgae are sources of accessible protein and fatty acids. More than 400 manuscripts were published per year in the last 4 years. Furthermore, industrial approaches utilizing these microorganisms are resulting in new jobs and services. This is in line with the global strategy for bioeconomy that aims to support sustainable development of bio-based sectors. Despite the recognized potential of the microalgal biomass value chain, significant knowledge gaps still exist especially regarding their optimized production and utilization. This review highlights the potential of microalgae and cyanobacteria for food and food-related applications as well as their market size. The chosen topics also include advanced production as mixed microbial communities, production of high-value biomolecules, photopro-duction of terpenoid flavoring compounds, their utilization for sustainable agriculture, applica-tion as source of nutrients in space, and a comparison with heterotrophic microorganisms like yeast to better evaluate their advantages over existing nutrient sources. This comprehensive assessment should stimulate further interest in this highly relevant research topic.
|
|
| 10. |
- Belotcerkovtceva, Daria, et al.
(author)
-
Insights and Implications of Intricate Surface Charge Transfer and sp3-Defects in Graphene/Metal Oxide Interfaces
- 2022
-
In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:31, s. 36209-36216
-
Journal article (peer-reviewed)abstract
- Adherence of metal oxides to graphene is of fundamental significance to graphene nanoelectronic and spintronic interfaces. Titanium oxide and aluminum oxide are two widely used tunnel barriers in such devices, which offer optimum interface resistance and distinct interface conditions that govern transport parameters and device performance. Here, we reveal a fundamental difference in how these metal oxides interface with graphene through electrical transport measurements and Raman and photoelectron spectroscopies, combined with ab initio electronic structure calculations of such interfaces. While both oxide layers cause surface charge transfer induced p-type doping in graphene, in sharp contrast to TiOx, the AlOx/graphene interface shows the presence of appreciable sp3 defects. Electronic structure calculations disclose that significant p-type doping occurs due to a combination of sp3 bonds formed between C and O atoms at the interface and possible slightly off-stoichiometric defects of the aluminum oxide layer. Furthermore, the sp3 hybridization at the AlOx/graphene interface leads to distinct magnetic moments of unsaturated bonds, which not only explicates the widely observed low spin-lifetimes in AlOx barrier graphene spintronic devices but also suggests possibilities for new hybrid resistive switching and spin valves.
|
|
