| 1. |
- A. da Cruz, Marcia Gabriely, et al.
(författare)
-
Biocoatings and additives as promising candidates for ultralow friction systems
- 2021
-
Ingår i: Green Chemistry Letters and Reviews. - : Informa UK Limited. - 1751-8253 .- 1751-7192. ; 14:2, s. 356-379
-
Forskningsöversikt (refereegranskat)abstract
- The achievement of frictionless systems, known as superlubricity, has become of great importance concerning energy saving and emission reduction. In parallel, the drive toward sustainability and environmental aspects has led to intense advances in the research and development of biobased materials. From the standpoint of Green Chemistry principles, this review presents a critical overview of the latest findings and future perspectives on the application of biobased materials aiming at superlubricant pursuits. The progress in the use of biomacromolecules, such as chitosan, cellulose, and lignin, as additives to lubricants or coating materials, are addressed, as well as the advances on sustainable coatings based on diamond-like carbon (DLC). Deeper investigations on the development of non-hazardous processes dedicated to the tribological properties of DLC, such as electrochemical synthesis using environment-friendly solvents to generate molecular precursors, widen the perspectives to achieve sustainable materials. Besides, the exploration of the tribochemical interactions between the DLC surface and lubricants containing biobased materials arises as a promising strategy to achieve green superlubricity as a viable and scalable process, through different pathways: by hydrogen bonds between lubricant and additives, via surface passivation of the functional groups present in these biomacromolecules or by biomimicking natural joints.
|
|
| 2. |
- Al-Najjar, Basim, 1954-, et al.
(författare)
-
Technologies needed for Smart Pro meeting industrial challenges and problems
- 2021
-
Rapport (refereegranskat)abstract
- The major goal of the pre-study is to identify and prepare the required information, knowledge, tools, modules, and technologies for a project within Smart Manufacturing in the spirit of the collaboration between Sweden and India.WP3 focus is: Identification of the technologies needed to be considered in Smart-Pro project as an Innovation action. This means that the input technologies that will be identified in the Pre-study project should be in about TRL 3-, and the demonstrated results of Smart-Pro should be in about TRL 6-7. Smart Pro project will be based on effective collaboration between universities/research institutes and industry.In WP3, we will develop a list of the tools, methods, modules and technologies (in the areas below) which are available at the members of the Pre-study consortium (and in industry in general), and necessary for developing Smart-Pro system.According to the project description, WP3 has two Tasks:• T3.1: Production-maintenance technologies needed for Smart-Pro.• T3.2: Communication and integration technologies needed for Smart-Pro.The tasks have been distributed between E-maintenance AB (Emaint), which the leader of the WP and the two tasks, Linnaeus University (LNU), Uppsala University (UU) and Stockholm University (SU).
|
|
| 3. |
- Budnyak, Tetyana, et al.
(författare)
-
LignoPhot : Conversion of hydrolysis lignin into the photoactive hybrid lignin/Bi4O5Br2/BiOBr composite for simultaneous dyes oxidation and Co2+ and Ni2+ recycling
- 2021
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 279
-
Tidskriftsartikel (refereegranskat)abstract
- Valorization of lignin is still an open question and lignin has therefore remained an underutilized biomaterial. This situation is even more pronounced for hydrolysis lignin, which is characterized by a highly condensed and excessively cross-linked structure. We demonstrate the synthesis of photoactive lignin/Bi4O5Br2/BiOBr bio-inorganic composites consisting of a lignin substrate that is coated by semiconducting nanosheets. The XPS analysis reveals that growing these nanosheets on lignin instead on cellulose prevents the formation of Bi5+ ions at the surface region, yielding thus a modified hetero-junction Bi4O5Br2/BiOBr. The material contains 18.9% of Bi4O5Br2/BiOBr and is effective for the photocatalytic degradation of cationic methylene blue (MB) and zwitterionic rhodamine B (RhB) dyes under light irradiation. Lignin/Bi4O5Br2/BiOBr decreases the dye concentration from 80 mg L-1 to 12.3 mg L-1 for RhB (85%) and from 80 mg L-1 to 4.4 mg L-1 for MB (95%). Complementary to the dye degradation, the lignin as a main component of the composite, was found to be efficient and rapid biosorbent for nickel, lead, and cobalt ions. The low cost, stability and ability to simultaneously photo-oxidize organic dyes and adsorb metal ions, make the photoactive lignin/Bi4O5Br2/BiOBr composite a prospective material for textile wastewaters remediation and metal ions recycling.
|
|
| 4. |
- Budnyak, Tetyana, et al.
(författare)
-
Nucleotide Interaction with a Chitosan Layer on a Silica Surface : Establishing the Mechanism at the Molecular Level
- 2021
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:4, s. 1511-1520
-
Tidskriftsartikel (refereegranskat)abstract
- The growing interest in gene therapy is coupled with the strong need for the development of safe and efficient gene transfection vectors. A composite based on chitosan and fumed silica has been found to be a prospective gene delivery carrier. This study presents an investigation of the nature of the bonds between a series of nucleotides with a chitosan layer deposited on a fumed silica surface. Experimentally measured surface complex formation constants (logK) of the nucleotides were found to be in the range of 2.69–4.02, which is higher than that for the orthophosphate (2.39). Theoretically calculated nucleotide complexation energies for chitosan deposited on the surface range from 11.5 to 23.0 kcal·mol–1, in agreement with experimental data. The adsorption of nucleotides was interpreted using their calculated speciation in an aqueous solution. Based on the structures of all optimized complexes determined from quantum-chemical PM6 calculations, electrostatic interactions between the surface-located NH3+ groups and −PO3H––/–PO32– fragments of the nucleotides were identified to play the decisive role in the adsorption mechanism. The saccharide fragment of monophosphates also plays an important role in the binding of the nucleotides to chitosan through the creation of hydrogen bonds.
|
|
| 5. |
- Chen, Zheng, et al.
(författare)
-
Graphitic nitrogen in carbon catalysts is important for the reduction of nitrite as revealed by naturally abundant N-15 NMR spectroscopy
- 2021
-
Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; :20
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state N-15 NMR (ssNMR) spectroscopy is a powerful tool for the determination of such positions in N-doped carbon at natural N-15 isotope abundance. Here we report a green chemistry approach for the synthesis of N-doped carbon using cellulose as a precursor, and a study of the catalytic properties and atomic structures of the related catalyst. N-doped carbon (NH3) was obtained by the oxidation of cellulose with HNO3 followed by ammonolysis at 800 degrees C. It had a N content of 6.5 wt% and a surface area of 557 m(2) g(-1), and N-15 ssNMR spectroscopy provided evidence for graphitic nitrogen besides regular pyrrolic and pyridinic nitrogen. This structural determination allowed probing the role of graphitic nitrogen in electrocatalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitrite reduction reaction. The N-doped carbon catalyst (NH3) showed higher electrocatalytic activities in the OER and HER under alkaline conditions and higher activity for nitrite reduction, as compared with a catalyst prepared by the carbonization of HNO3-treated cellulose in N-2. The electrocatalytic selectivity for nitrite reduction of the N-doped carbon catalyst (NH3) was directly related to the graphitic nitrogen functions. Complementary structural analyses by means of C-13 and H-1 ssNMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature N-2 adsorption were performed and provided support to the findings. The results show that directly-excited N-15 ssNMR spectroscopy at natural N-15 abundance is generally capable of providing information on N-doped carbon materials if relaxation properties are favorable. It is expected that this approach can be applied to a wide range of solids with an intermediate concentration of N atoms.
|
|
| 6. |
- de Deus, Wevernilson F., et al.
(författare)
-
Curcuminoid-Tailored Interfacial Free Energy of Hydrophobic Fibers for Enhanced Biological Properties
- 2021
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:21, s. 24493-24504
-
Tidskriftsartikel (refereegranskat)abstract
- The ability of mimicking the extracellular matrix architecture has gained electrospun scaffolds a prominent space into the tissue engineering field. The high surface-to-volume aspect ratio of nanofibers increases their bioactivity while enhancing the bonding strength with the host tissue. Over the years, numerous polyesters, such as poly(lactic acid) (PLA), have been consolidated as excellent matrices for biomedical applications. However, this class of polymers usually has a high hydrophobic character, which limits cell attachment and proliferation, and therefore decreases biological interactions. In this way, functionalization of polyester-based materials is often performed in order to modify their interfacial free energy and achieve more hydrophilic surfaces. Herein, we report the preparation, characterization, and in vitro assessment of electrospun PLA fibers with low contents (0.1 wt %) of different curcuminoids featuring pi-conjugated systems, and a central beta-diketone unit, including curcumin itself. We evaluated the potential of these materials for photochemical and biomedical purposes. For this, we investigated their optical properties, water contact angle, and surface features while assessing their in vitro behavior using SH-SY5Y cells. Our results demonstrate the successful generation of homogeneous and defect-free fluorescent fibers, which are noncytotoxic, exhibit enhanced hydrophilicity, and as such greater cell adhesion and proliferation toward neuroblastoma cells. The unexpected tailoring of the scaffolds' interfacial free energy has been associated with the strong interactions between the PLA hydrophobic sites and the nonpolar groups from curcuminoids, which indicate its role for releasing hydrophilic sites from both parts. This investigation reveals a straightforward approach to produce photoluminescent 3D-scaffolds with enhanced biological properties by using a polymer that is essentially hydrophobic combined with the low contents of photoactive and multifunctional curcuminoids.
|
|
| 7. |
- Guo, Hua, et al.
(författare)
-
Barium Titanium Oxynitride from Ammonia-Free Nitridation of Reduced BaTiO3
- 2021
-
Ingår i: Inorganics. - : MDPI AG. - 2304-6740. ; 9:8
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the nitridation of reduced BaTiO3, BaTiO2.60H0.08, corresponding to an oxyhydride with a large concentration of O defects (>10%). The material is readily nitrided under flowing N2 gas at temperatures between 400 and 450 °C to yield oxynitrides BaTiO2.6Nx (x = 0.2−0.22) with a slightly tetragonally distorted perovskite structure, a ≈ 4.01 and c ≈ 4.02 Å, and Ti partially remaining in the oxidation state III. The tetragonal structure was confirmed from Raman spectroscopy. 14N MAS NMR spectroscopy shows a single resonance at 270 ppm, which is typical for perovskite transition metal oxynitrides. However, largely different signal intensity for materials with very similar N content suggests N/O/vacancy ordering when prolonging nitridation times to hours. Diffuse reflectance UV-VIS spectroscopy shows a reduction of the intrinsic band gap to 2.4–2.45 eV compared to BaTiO3 (~3.2 eV). Mott-Schottky measurements confirm n-type conductivity and reveal a slight negative shift of the conduction band edge from –0.59 V (BaTiO3) to ~–0.65 eV.
|
|
| 8. |
- Jaworski, Aleksander, et al.
(författare)
-
14N, 13C, and 119Sn solid-state NMR characterization of tin(II) carbodiimide Sn(NCN)
- 2021
-
Ingår i: Zeitschrift für Naturforschung. B, A journal of chemical sciences. - : Walter de Gruyter GmbH. - 0932-0776 .- 1865-7117. ; 76:10-12, s. 745-750
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first magic-angle spinning (MAS) nuclear magnetic resonance (NMR) study on Sn(NCN). In this compound the spatially elongated (NCN)(2)- ion is assumed to develop two distinct forms: either cyanamide (NEC-N2-) or carbodiimide (N-=C=N-). Our N-14 MAS NMR results reveal that in Sn(NCN) the (NCN)(2-) groups exist exclusively in the form of symmetric carbodiimide ions with two equivalent nitrogen sites, which is in agreement with the X-ray diffraction data. The N-14 quadrupolar coupling constant vertical bar C-Q vertical bar approximate to 1.1 MHz for the N-=C=N- ion in Sn(NCN) is low when compared to those observed in molecular compounds that comprise cyano-type N C- moieties (vertical bar C-Q vertical bar > 3.5 MHz). This together with the information from N-14 and C-13 chemical shifts indicates that solid-state NMR is a powerful tool for providing atomic-level insights into anion species present in these compounds. The experimental NMR results are corroborated by high-level calculations with quantum chemistry methods.
|
|
| 9. |
- Lu, Can, et al.
(författare)
-
Sensibilization of p-NiO with ZnSe/CdS and CdS/ZnSe quantum dots for photoelectrochemical water reduction
- 2021
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 13:2, s. 869-877
-
Tidskriftsartikel (refereegranskat)abstract
- Core/shell quantum dots (QDs) paired with semiconductor photocathodes for water reduction have rarely been implemented so far. We demonstrate the integration of ZnSe/CdS and CdS/ZnSe QDs with porous p-type NiO photocathodes for water reduction. The QDs demonstrate appreciable enhancement in water-reduction efficiency, as compared with the bare NiO. Despite their different structure, both QDs generate comparable photocurrent enhancement, yielding a 3.8- and 3.2-fold improvement for the ZnSe/CdS@NiO and CdS/ZnSe@NiO system, respectively. Unraveling the carrier kinetics at the interface of these hybrid photocathodes is therefore critical for the development of efficient photoelectrochemical (PEC) proton reduction. In addition to examining the carrier dynamics by the Mott–Schottky technique and electrochemical impedance spectroscopy (EIS), we performed theoretical modelling for the distribution density of the carriers with respect to electron and hole wave functions. The electrons are found to be delocalized through the whole shell and can directly actuate the PEC-related process in the ZnSe/CdS QDs. The holes as the more localized carriers in the core have to tunnel through the shell before injecting into the hole transport layer (NiO). Our results emphasize the role of interfacial effects in core/shell QDs-based multi-heterojunction photocathodes.
|
|
| 10. |
- Ma, Zili, et al.
(författare)
-
CeTiO2N oxynitride perovskite : paramagnetic N-14 MAS NMR without paramagnetic shifts
- 2021
-
Ingår i: Zeitschrift für Naturforschung. B, A journal of chemical sciences. - : Walter de Gruyter GmbH. - 0932-0776 .- 1865-7117. ; 76:5, s. 275-280
-
Tidskriftsartikel (refereegranskat)abstract
- N-14 magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of diamagnetic LaTiO2N perovskite oxynitride and its paramagnetic counterpart CeTiO2N are presented. The latter, to the best of our knowledge, constitutes the first high-resolution N-14 MAS NMR spectrum collected from a paramagnetic solid material. The unpaired 4f-electrons in CeTiO2N do not induce a paramagnetic N-14 NMR shift. This is remarkable given the direct Ce-N contacts in the structure for which ab initio calculations predict substantial Ce -> N-14 contact shift interaction. The same effect is revealed with N-14 MAS NMR for SrWO2N (unpaired 5d-electrons).
|
|
| 11. |
- Ma, Zili, et al.
(författare)
-
Combining Electrocatalysts and Biobased Adsorbents for Sustainable Denitrification
- 2021
-
Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:10, s. 3651-3660
-
Tidskriftsartikel (refereegranskat)abstract
- Efficient treatment of domestic and industrial wastewater is one of the major challenges of the 21st century. Among the inorganic pollutants, nitrogen species are significant contaminants and the management of the nitrogen cycle is one the most crucial parts of wastewater purification. Herein, we report an integrated method that minimizes the amount of chemicals used, can be empowered by renewable energy, uses renewables materials for ammonia recovery, and is scalable. Complete denitrification of wastewater was achieved by combining electrochemical and adsorption treatment for real wastewater samples from the Stockholm water pilot plant. About 98% of nitrate was selectively converted to ammonia over abundant copper electrocatalysts in the presence of Na2SO4-supporting electrolyte at -0.6 V vs reversible hydrogen electrode (RHE) within 3 h. The valorized nitrate in the form of ammonia could be recovered by means of cheap kraft lignin-SiO2 sorbents to achieve total denitrification. The presented method is economically feasible, scalable, and contributes to sustainable recycling within a circular economy.
|
|
| 12. |
- Ma, Zili, et al.
(författare)
-
Structural Properties of NdTiO2+xN1-x and Its Application as Photoanode
- 2021
-
Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 60:2, s. 919-929
-
Tidskriftsartikel (refereegranskat)abstract
- Mixed-anion inorganic compounds offer diverse functionalities as a function of the different physicochemical characteristics of the secondary anion. The quaternary metal oxynitrides, which originate from substituting oxygen anions (O2-) in a parent oxide by nitrogen (N3-), are encouraging candidates for photoelectrochemical (PEC) water splitting because of their suitable and adjustable narrow band gap and relative negative conduction band (CB) edge. Given the known photochemical activity of LaTiO2N, we investigated the paramagnetic counterpart NdTiO2+xN1-x. The electronic structure was explored both experimentally and theoretically at the density functional theory (DFT) level. A band gap (E-g) of 2.17 eV was determined by means of ultraviolet-visible (UV-vis) spectroscopy, and a relative negative flat band potential of -0.33 V vs reversible hydrogen electrode (RHE) was proposed via Mott-Schottky measurements. N-14 solid state nuclear magnetic resonance (NMR) signals from NdTiO2+xN1-x could not be detected, which indicates that NdTiO2+xN1-x is berthollide, in contrast to other structurally related metal oxynitrides. Although the bare particle-based photoanode did not exhibit a noticeable photocurrent, Nb2O5 and CoOx overlayers were deposited to extract holes and activate NdTiO2+xN1-x. Multiple electrochemical methods were employed to understand the key features required for this metal oxynitride to fabricate photoanodes.
|
|
| 13. |
- Moreno, Adrian, et al.
(författare)
-
Unravelling the Hydration Barrier of Lignin Oleate Nanoparticles for Acid- and Base-Catalyzed Functionalization in Dispersion State
- 2021
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:38, s. 20897-20905
-
Tidskriftsartikel (refereegranskat)abstract
- Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions. The high stability of OLNPs is attributed to the alkyl chains accumulated in the shell of the particle, which delays protonation/deprotonation of carboxylic acid and phenolic hydroxyl groups. Owing to the enhanced stability, acid- and base-catalyzed functionalization of OLNPs at pH 2.0 and pH 12.0 via oxirane ring-opening reactions were successfully performed. We also demonstrated these new functionalized particles as efficient pH-switchable dye adsorbents and anticorrosive particulate coatings.
|
|
| 14. |
- Piątek, Jędrzej, et al.
(författare)
-
Toward Sustainable Li-Ion Battery Recycling : Green Metal-Organic Framework as a Molecular Sieve for the Selective Separation of Cobalt and Nickel
- 2021
-
Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:29, s. 9770-9778
-
Tidskriftsartikel (refereegranskat)abstract
- The growing demand for Li-ion batteries (LIBs) has made their postconsumer recycling an imperative need toward the recovery of valuable metals, such as cobalt and nickel. Nevertheless, their recovery and separation from active cathode materials in LIBs, via an efficient and environmentally friendly process, have remained a challenge. In this work, we approach a simple and green method for the selective separation of nickel ions from mixed cobalt-nickel aqueous solutions under mild conditions. We discovered that the bioinspired microporous metal-organic framework (MOF) SU-101 is a selective sorbent toward Ni2+ ions at pH 5-7 but does not adsorb Co2+ ions. According to the Freundlich isotherm, the adsorption capacity toward Ni2+ reached 100.9 mg.g(-1), while a near-zero adsorption capacity was found for Co2+ ions. Ni2+ removal from aqueous solutions was performed under mild conditions (22 degrees C and pH 5), with a high yield up to 96%. The presence of Ni2+ ions adsorbed on the surface of the material has been proven by solid-state H-1 nuclear magnetic resonance spectroscopy. Finally, the separation of Ni2+ from Co2+ from binary solutions was obtained with approximately 30% yield for Ni2+, with a near-zero adsorption of Co2+, which has been demonstrated by UV-vis spectroscopy. The ion adsorption process of Ni2+ and Co2+ ions was additionally studied by means of classical molecular dynamics calculations (force fields), which showed that the Ni2+ ions were more prone to enter the MOF canals by replacing some of their coordinated water molecules. These results offer a green pathway toward the recycling and separation of valuable metals from cobalt-containing LIBs while providing a sustainable route for waste valorization in a circular economy.
|
|
| 15. |
- Rokicińska, Anna, et al.
(författare)
-
Impact of Mn addition on catalytic performance of Cu/SiBEA materials in total oxidation of aromatic volatile organic compounds
- 2021
-
Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 546
-
Tidskriftsartikel (refereegranskat)abstract
- Dealuminated BEA zeolite (SiBEA) was chosen as a support of metal oxide(s) phase for catalytic combustion of volatile organic compounds (VOCs). Copper and/or manganese oxide(s) were deposited at various Cu/Mn molar ratios. Factors influencing the catalytic activity were found by chosen physicochemical methods, including XRD, XRF, low-temperature N-2 adsorption, FT-IR, UV-Vis-DRS, STEM-EDX, XPS and H-2-TPR. Depending on the chemical composition, CuO, (CuxMn3-x)(1-delta)O-4, Cu-doped Mn3O4 or Mn2O3 was formed as the dominant phase. The active phase particles were located mainly in the interparticle voids of the zeolite support. SiBEA gained Lewis acid sites after the introduction of the metal oxide phase, especially in the case of CuO deposition. The presence of copper in the catalytic system resulted in enhanced reducibility of the active phase, and in a consequence in high catalytic activity in the total oxidation of aromatic VOCs, which proceeds according to the Mars-van Krevelen mechanism. After the introduction of Mn, the co-existence of different valence forms was found due to the redox equilibrium: Cu2+ + Mn3+ = Cu+ + Mn4+. Definitely, the addition of Mn to Cu/SiBEA increased the number of available surface vacancies and had a beneficial effect on the catalytic performance.
|
|
| 16. |
- Thersleff, Thomas, et al.
(författare)
-
Soot Nanoparticles Generated from Tribofilm Decomposition under Real Engine Conditions for Identifying Lubricant Hazards
- 2021
-
Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 4:1, s. 220-228
-
Tidskriftsartikel (refereegranskat)abstract
- Lubrication of an internal combustion engine is critical for energy and material losses. Engine lubricants contain a number of functional additives including zinc dialkyldithiophosphate, which is a commonly used antiwear additive that forms by in situ decomposition a protective interface at the metal surface. Here, we present a detailed nanoscale investigation of carbonaceous soot nanoparticles generated from real engine conditions. By combining macroscale XPS with high-resolution STEM-EELS-EDX, we reveal that such a soot nanoparticle matrix contains also 3-5 nm ZnO-based nanoparticles with additions of phosphorus and sulfur, originating from the organometallic antiwear additive. Under the consideration of the obtained chemical information on the carbonaceous matrix and (ZnO:P,S) nanoparticles and the generally known suggestion of potential toxicity for soot nanoparticles, our method allows us to predict nanoparticle-based hazards from mechanochemical applications and also their formation mechanism. These are critical information and also the basis of toxicity assessment, both for theoretical predictions and experimental testing for the estimation of overall life-cycle analysis, including the environmental impact. Our results unravel the tribofilm decomposition under real field conditions and hint toward potentially unidentified toxicological nanoparticle hazards with respect to organophosphate-containing lubricants.
|
|
| 17. |
- Zhang, Tong, et al.
(författare)
-
Atomic-Level Understanding for the Enhanced Generation of Hydrogen Peroxide by the Introduction of an Aryl Amino Group in Polymeric Carbon Nitrides
- 2021
-
Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 11:22, s. 14087-14101
-
Tidskriftsartikel (refereegranskat)abstract
- Heterogeneous catalysts are often “black boxes” due to the insufficient understanding of the detailed mechanisms at the catalytic sites. An atomic-level elucidation of the processes taking place in those regions is, thus, mandatory to produce robust and selective heterogeneous catalysts. We have improved the description of the whole reactive scenario for polymeric carbon nitrides (PCN) by combining atomic-level characterizations with magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy, classical reactive molecular dynamics (RMD) simulations, and quantum chemistry (QC) calculations. We disclose the structure–property relationships of an ad hoc modified PCN by inserting an aryl amino group that turned out to be very efficient for the production of H2O2. The main advancement of this work is the development of a difluoromethylene-substituted aryl amino PCN to generate H2O2 at a rate of 2.0 mM·h–1 under the irradiation of household blue LEDs and the identification of possible active catalytic sites with the aid of 15N and 19F MAS solid-state NMR without using any expensive labeling reagent. RMD simulations and QC calculations confirm and further extend the experimental descriptions by revealing the role and locations of the identified functionalities, namely, NH linkers, −NH2 terminal groups, and difluoromethylene units, reactants, and products.
|
|
