Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros











Base de dados
Assunto principal
Intervalo de ano de publicação
1.
Dalton Trans ; 2024 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-39665278

RESUMO

In this study, the potential of the metal-organic framework UTSA-16(Zn) as a fluorescence detector for SO2 is explored. The material was synthesized and characterized by powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), and its fluorescence behavior was analyzed before and after SO2 exposure. A significant decrease in fluorescence intensity was observed and a LOD of 1.79 mM (∼114.6 ppm) was obtained. With the help of time-resolved photoluminescence (TRPL) experiments and X-ray photoelectron (XPS) and ultraviolet-visible (UV-vis) spectroscopy, a static quenching mechanism due to the formation of a non-fluorescent complex in the ground state (GSC) was elucidated.

2.
Small ; : e2408155, 2024 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-39501986

RESUMO

The first experimental investigation of a porous organic cage (POC) for the challenging task of H2S capture is reported. The N-containing cage molecular material, a tertiary amine POC (6FT-RCC3), demonstrates the highest H2S (hydrogen sulfide) capture (record capacity) for a porous material at room temperature and atmospheric pressure (20.6 mmol H2S g-1; 25 H2S molecules per cage) combined with excellent reversibility for at least five adsorption-desorption cycles. In situ FTIR spectroscopy, solid-state 13C, and 15N CP MAS NMR spectroscopy experiments are applied to investigate the adsorption mechanism, identifying relatively weak interactions via hydrogen bonding. In addition, the fluorescence performances of this POC material are evaluated for the detection and sensing of H2S, where a clear H2S selectivity is observed over other gases. Remarkably, the limit of detection (LOD) is calculated to be 0.13 mm (≈4.43 ppm) in a tetrahydrofuran (THF) solution of H2S.

3.
Dalton Trans ; 53(29): 12208-12214, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38973674

RESUMO

The development of adsorbents for air pollutant remediation and effective monitoring is of interest. Then, the effect of the APTES functionalization ratio on the impact of the adsorption and detection of SO2 molecules was evaluated. The higher APTES functionalization material (SBA-15_6.1APTES) shows a high uptake of 1.15 mmol g-1 at 0.001 bar and 298 K. Fluorescence, time-resolved photoluminescence, and quantum yield experiments revealed a turn-on effect specifically for SO2 molecules, indicating high selectivity, suggesting host-to-guest energy transfer. Attractively, XPS measurement provided an understanding of the mechanism, suggesting hydrogen bonding and dipole-dipole interactions as the main interactions between SO2 molecules and SBA-15_6.1APTES. DFT calculations were performed to confirm these interactions. Furthermore, this study highlights the application of SBA-15 materials with different amino modifications for SO2 treatment and provides insight into the interaction mechanism using experimental techniques.

4.
Chem Commun (Camb) ; 60(29): 3970-3973, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38501603

RESUMO

SO2 emissions not only affect local air quality but can also contribute to other environmental issues. Developing low-cost and robust adsorbents with high uptake and selectivity is needed to reduce SO2 emissions. Here, we show the SO2 adsorption-desorption capacity of carbon microfibers (CMFs) at 298 K. CMFs showed a reversible SO2 uptake capacity (5 mmol g-1), cyclability over ten adsorption cycles with fast kinetics and good selectivity towards SO2/CO2 at low-pressure values. Additionally, CMFs' photoluminescence response to SO2 and CO2 was evaluated.

5.
Dalton Trans ; 53(10): 4790-4796, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38372055

RESUMO

The Al(III)-based MOF CYCU-3 exhibits a relevant SO2 adsorption performance with a total uptake of 11.03 mmol g-1 at 1 bar and 298 K. CYCU-3 displays high chemical stability towards dry and wet SO2 exposure. DRIFTS experiments and computational calculations demonstrated that hydrogen bonding between SO2 molecules and bridging Al(III)-OH groups are the preferential adsorption sites. In addition, photoluminescence experiments demonstrated the relevance of CYCU-3 for application in SO2 detection with good selectivity for SO2 over CO2 and H2O. The change in fluorescence performance demonstrates a clear turn-on effect after SO2 interaction. Finally, the suppression of ligand-metal energy transfer along with the enhancement of ligand-centered π* → π electronic transition was proposed as a plausible fluorescence mechanism.

6.
Nanoscale Horiz ; 9(3): 472-478, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38240821

RESUMO

CsPbBr3 nanocrystals (NCs) are promising optoelectronic and catalytic materials. Manipulating their morphology can improve their properties and stability. In this work, an alkene-derived zwitterionic ligand was used to control the morphology of CsPbBr3 NCs to yield the highly unusual rhombicuboctahedron morphology, showcasing the first example of a surfactant-tail controlled growth.

7.
Dalton Trans ; 52(35): 12490-12495, 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37602766

RESUMO

A non-porous version of SU-101 (herein n-SU-101) was evaluated for the CO2 cycloaddition reaction. The findings revealed that open metal sites (Bi3+) are necessary for the reaction. n-SU-101 displays a high styrene oxide conversion of 96.6% under mild conditions (3 bar and 80 °C). The catalytic activity of n-SU-101 demonstrated its potential application for the cycloaddition of CO2 using styrene oxide.

8.
Nanoscale ; 15(30): 12471-12475, 2023 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-37462135

RESUMO

The MOF-type Ni2(dobpdc) shows a high chemical stability towards SO2, high capacity for SO2 capture at low pressure (4.3 mmol g-1 at 298 K and up to 0.05 bar), and exceptional cycling performance. Fluorescence experiments demonstrated the SO2 detection properties of Ni2(dobpdc) with a remarkable SO2 detection selectivity. Finally, time-resolved photoluminescence experiments provided a plausible mechanism of SO2 detection by this Ni(II)-based MOF material.

9.
Chem Commun (Camb) ; 59(52): 8115-8118, 2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37306073

RESUMO

Modulated self-assembly protocols are used to develop facile, HF-free syntheses of the archetypal flexible PCP, MIL-53(Cr), and novel isoreticular analogues MIL-53(Cr)-Br and MIL-53(Cr)-NO2. All three PCPs show good SO2 uptake (298 K, 1 bar) and high chemical stabilities against dry and wet SO2. Solid-state photoluminescence spectroscopy indicates all three PCPs exhibit turn-off sensing of SO2, in particular MIL-53(Cr)-Br, which shows a 2.7-fold decrease in emission on exposure to SO2 at room temperature, indicating potential sensing applications.

10.
ChemSusChem ; 16(3): e202201505, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36445827

RESUMO

Two-dimensional (2D) organic-inorganic hybrid perovskites have rapidly become an attractive alternative to three-dimensional (3D) perovskites as solar cell absorbers, owing to their improved stability, versatility, and ease of processing. Despite their advantages, the insulating nature of the organic cations makes these materials have lower absorbing and conducting properties, resulting in lower device efficiencies. A way to circumvent these issues is the integration of functional molecules that help mitigate these limitations. In this study, six new perovskites composed of three distinct diynes are synthesized, all of which can be thermally polymerized to form conjugated polymers within the perovskite layers. The incorporation of conjugated polymers results in drastic changes in these materials' optoelectronic properties and their overall stability. Furthermore, depending on the nature of the diyne and the inorganic layers, the materials show varying polymerization yields, optical bandgaps, and charge carrier densities. These results afford significant insight into the chemical nature of the polymerized species and thus highlight the versatility of this approach to post-synthetically generate conducting polymers within the layers of 2D perovskites, paving the way toward their use in optoelectronic devices.

11.
Dalton Trans ; 51(48): 18368-18372, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36268816

RESUMO

The SO2 adsorption-desorption capacity at room temperature and 1 bar of the metal-organic polyhedron MOP-CDC was investigated. In addition, the qualitative solid-state absorption-emission properties of this material (before and after SO2 exposure) were measured and tested, and it demonstrated remarkable capability for SO2 detection. Our results represent the first example of fluorimetric SO2 detection in a MOP.


Assuntos
Metais , Adsorção
12.
J Phys Chem Lett ; 11(24): 10362-10367, 2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33232165

RESUMO

Layered double perovskites have the potential to further expand the vast space of optoelectronic properties and applications of halide perovskites. Among the ∼60 known members, to date only the ⟨111⟩-oriented layered double perovskites, Cs4Cd1-xMnxBi2Cl12, have shown efficient photoluminescence (PL). The replacement of Bi with Sb in these materials was investigated, resulting in two new families of layered inorganic perovskite alloys with full solubility. The first, Cs4Cd1-xMnxSb2Cl12, exhibits a PL emission at 605 nm ascribed to Mn2+ centers, with a maximum quantum yield of 28.5%. The second, Cs4Cd0.8Mn0.2(Sb1-yBiy)2Cl12, contains a fixed amount of Mn2+ and Cd2+ but variable Sb3+ and Bi3+ concentrations. We observed a decreased efficiency of the Cs4Cd1-xMnxSb2Cl12 family compared to that of Cs4Cd1-xMnxBi2Cl12, which was attributed to a decreased spin-orbit and Jahn-Teller couplings in Sb and the subsequent increased electronic delocalization. The present work lays out a roadmap to achieve high photoluminescence efficiencies in layered double perovskites.

13.
ACS Omega ; 5(28): 17304-17313, 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32715215

RESUMO

Calcium scaling is a serious problem encountered in the oil and gas industry because it is common that brines produced alongside oil and gas exhibit high concentrations of calcium ions, among others, which is expensive to remedy. The precipitation of calcium salts on the internal wall of the pipelines may occur because of the physical and chemical changes as fluids are produced from downhole to surface facilities. Although different researchers have address scaling and corrosion in the oil and gas industry, there are few reports in the literature relating the corrosion and scaling phenomena simultaneously. Despite there being indications that scales may produce corrosion problems, affecting the mechanical integrity of the infrastructure, there is minimal research in the literature addressing such relations. Previous studies presented aluminum alloys as excellent and reliable materials for applications in the petroleum industry, such as drilling activities. In this work, we evaluate the corrosion behavior of steel and aluminum alloys under highly scaling environments using supersaturated brines. Our results show that the presence of calcium carbonate and calcium sulfate as a scaling environment increases the corrosion rates for aluminum alloys and carbon steel; however, the same environments do not affect the corrosion behavior of stainless steel.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA