A modified MOF named UiO-66-NH2-SA was synthesized based on the covalent post synthetic attachment of the MOFs (UiO-66-NH2) and salicylaldehyde via a Schiff-base reaction. The as-prepared ...functionalized UiO-66-NH2-SA not only maintains its structural integrity during the PSM process, but also shows excellent luminescence and good fluorescence stability in water. It was further utilized as a novel fluorescent probe for detecting of Al3+. The fluorescence intensity of UiO-66-NH2-SA increased linearly upon increasing the concentration of Al3+ in the range of 0–500 μM with a detection limit of 6.98 μM. The possible mechanism is discussed. This study presents a new ratiometric and colorimetric Al3+ fluorescent sensor. The good fluorescence stability of UiO-66-NH2-SA in aqueous media, the low detection limit and the broad linear in sensing Al3+ indicate its high potential in practical applications.
Metal‐containing nanoparticles (M‐NPs) in metal/nitrogen‐doped carbon (M‐N‐C) catalysts have been considered hostile to the acidic oxygen reduction reaction (ORR). The relation between M‐NPs and the ...active sites of metal coordinated with nitrogen (MNx) is hard to establish in acid medium owing to the poor stability of M‐NPs. Herein, we develop a strategy to successfully construct a new FeCo‐N‐C catalyst containing highly active M‐NPs and MN4 composite sites (M/FeCo‐SAs‐N‐C). Enhanced catalytic activity and stability of M/FeCo‐SAs‐N‐C is shown experimentally. Calculations reveal that there is a strong interaction between M‐NPs and FeN4 sites, which can favor ORR by activating the O−O bond, thus facilitating a direct 4 e− process. Those findings firstly shed light on the highly active M‐NPs and FeN4 composite sites for catalyzing acid oxygen reduction reaction, and the relevant reaction mechanism is suggested.
Highly active metal‐containing nanoparticles and FeN4 composite sites have been constructed. Experiment and calculation results reveal the enormous potential for activating the O−O bond and promoting the direct 4 e− dissociation pathway in the acidic oxygen reduction reaction (ORR), which could fundamentally improve ORR activity and inhibit the formation of reactive oxygen species.
Smart materials are leading the future of materials by virtue of their autonomous response behavior to external stimuli; it is widely believed their development and application will bring a new ...revolution. Among them, vanadium dioxide (VO2) is a special one showing a unique multi-stimulus responsive metal–insulator transition (MIT) accompanied by a structural phase transition (SPT) with striking changes of physical properties including optical, electrical and thermal properties, etc., making it ideal for smart windows, micro-bolometers, actuators, etc. Since the attractive performances of VO2 are rooted in MIT behavior (coupled with SPT), element doping becomes a powerful tool in tailoring VO2 performance. Oriented on the practical requirements, element-doped VO2 is more promising and competitive in terms of performance, prospect, and cost. Here we focus specifically on element-doped VO2, the recent progress and potential challenges of which are discussed. We devote attention to the crucial roles of element doping in modulating the properties and driving the practicality of VO2, aiming to inspire current research to pioneer new applications of VO2.
A zirconium metallic organic framework UiO-66-NH2 has been synthesized and is further modified with imidazole-2-carboxaldehyde by a covalent post synthetic route which is based on a Schiff-base ...reaction. The as-prepared, functionalized MOF named UiO-66-NH2-IM is fully characterized. It retains its structural integrity during the PSM process and shows excellent luminescence and good fluorescence stability in water. It has also been further utilized as a sensitive fluorescent probe for sensing ions. The results show that UiO-66-NH2-IM can be developed into a highly selective and sensitive sensor for the detection of S2O82− (detection limit, 8.63 μM) and Fe3+ ions (detection limit, 4.95 μM) by fluorescence quenching of UiO-66-NH2-IM. All the possible mechanisms involved are discussed. Remarkably, it is the first covalent post-synthesized MOF to be developed as a colorimetric fluorescent sensor for the detection of S2O82− and Fe3+.
A novel europium functionalized metal–organic framework (MOF) named Eu3+@UiO-66-NH2-IM is robustly synthesized via covalent PSM (postsynthetic modification). The ligand of matrix MOF is covalently ...modified via imidazole-2-carboxaldehyde after the UiO-66-NH2 is synthesized. The successful transformation of amino groups to imine groups is confirmed by Fourier transform infrared spectra (FTIR) analysis. The modified MOF named UiO-66-NH2-IM shows outstanding crystalline stability. After Eu3+ is doped into UiO-66-NH2-IM, the as-prepared fluorescent MOF displays the characteristic emission line of Eu3+. Discussion of the tunable emission color of the modified MOF is included, and white-light integration could be achieved through altering the ratio of Eu3+ doped into the MOF. In addition, the luminescent transparent film based on Eu3+@UiO-66-NH2-IM can emit white light under proper excitation wavelength, which may be helpful to some potential applications in lighting. In addition, Eu3+@UiO-66-NH2-IM shows a different emission response in water and organic solvents, and it is further developed into a sensitive probe for the detection of water content in organic solvents (ethanol, DMF) with low detection limits (0.088 and 0.054%, respectively) by utilizing its quenching behavior in water. Meanwhile, Eu3+@UiO-66-NH2-IM displays a greatly selective and sensitive response for detecting aniline with a low detection limit (0.072%) and a broad linear range (0–3.75%), and the signal of the detection is obvious, which can be seen clearly under the irradiation of UV light.
Various kinds of optical responsive ceramic nanomaterials and films were successfully synthesized by environmental friendly green processes, such as hydrothermal/solvothermal process, mechanochemical ...doping process, oxygen plasma treatment process and a water molecular controlled-release solvothermal process (WCRSP). The composites combined the high-sensitive anion doped photocatalysts with up-conversion or long afterglow phosphors showed excellent deNOx photocatalytic activity under UV/ visible/NIR light irradiation, or even after turning off light irradiation. The mixed valence state tungsten based homogeneous nanomaterials possessed excellent IR light responsive properties, implied their potential applications as smart window materials and photothermal ablation cancer therapy materials. Significant contributions are expected for the development of optical responsive functional materials by green processes.
New York State (NYS) is an epicenter of the SARS-CoV-2 pandemic in the United States. Reliable estimates of cumulative incidence in the population are critical to tracking the extent of transmission ...and informing policies.
We conducted a statewide seroprevalence study in a 15,101 patron convenience sample at 99 grocery stores in 26 counties throughout NYS. SARS-CoV-2 cumulative incidence was estimated from antibody reactivity by first poststratification weighting and then adjusting by antibody test characteristics. The percent diagnosed was estimated by dividing the number of diagnoses by the number of estimated infection-experienced adults.
Based on 1887 of 15,101 (12.5%) reactive results, estimated cumulative incidence through March 29 was 14.0% (95% confidence interval CI: 13.3%–14.7%), corresponding to 2,139,300 (95% CI: 2,035,800–2,242,800) infection-experienced adults. Cumulative incidence was highest in New York City 22.7% (95% CI: 21.5%–24.0%) and higher among Hispanic/Latino (29.2%), non-Hispanic black/African American (20.2%), and non-Hispanic Asian (12.4%) than non-Hispanic white adults (8.1%, P < .0001). An estimated 8.9% (95% CI: 8.4%–9.3%) of infections in NYS were diagnosed, with diagnosis highest among adults aged 55 years or older (11.3%, 95% CI: 10.4%–12.2%).
From the largest U.S. serosurvey to date, we estimated >2 million adult New York residents were infected through late March, with substantial disparities, although cumulative incidence remained less than herd immunity thresholds. Monitoring, testing, and contact tracing remain essential public health strategies.
Herein, a hybrid, MIL-125(Ti)@TiO2, has been synthesized. It is composed of TiO2 and titanium metal–organic frameworks and has been further utilized as a catalyst for dye degradation. The ...as-synthesized hybrid MIL-125(Ti)@TiO2 has a characteristic property of ultraviolet light absorption. The combination of MOFs and its corresponding metal oxides, and to be further employed as a ultraviolet light photocatalyst, is relatively unexplored. In this study, a titanium metal–organic framework and titanium dioxide are combined, and the results indicate that the hybrid MIL-125(Ti)@TiO2 has better performance of UV-light-driven RhB degradation in an aqueous solution as compared to pure TiO2. The hybrid also possesses excellent stability during the photocatalytic process. Furthermore, the luminescence properties of MIL-125(Ti)@TiO2 were investigated in detail after Ln3+ (Eu3+, Tb3+, and Sm3+) ions were doped into the hybrid. The emission spectra of Ln@MIL-125(Ti)@TiO2 show characteristic emission lines of the corresponding lanthanide ion when Ln@MIL-125(Ti)@TiO2 is exposed to a proper excitation wavelength. Moreover, a discussion of the tunable emission color of Ln@MIL-125(Ti)@TiO2 is included. This study illustrates that Ln@MIL-125(Ti)@TiO2 has the potential for white light emission application as it can emit white light upon change in the ratio of Ln3+ in the hybrid and the excitation wavelength.
Noble metals usually work as the cocatalyst for photocatalytic water splitting, but their rare and expensive properties narrowed their wide development. Transition-metal sulfides have appeared to be ...promising non-noble metal cocatalysts in the hydrogen evolution reaction (HER) to meet future energy demands. Meanwhile, many studies focus on the fabrication of bimetallic catalysts because of their remarkably superior catalytic activity compared with monometallic substances. Herein, amorphous bimetallic cobalt nickel sulfide (CoNiS x ) was fabricated to work as a cocatalyst in the photocatalytic H2 evolution reaction, which can couple with pristine graphitic carbon nitride (g-C3N4). CoNiS x -CN exhibits a larger specific surface area compared with g-C3N4, making it possess more reaction active sites. Moreover, the contacted interface in the CoNiS x -CN composite photocatalyst contributes to higher separation efficiency of photogenerated carriers, which was proved by experimental and theoretical calculations. More importantly, the theoretical calculation also verified that CoNiS x -CN has relatively closer Gibbs free energy to zero than pure g-C3N4 and corresponding monometallic cocatalyzed g-C3N4. Therefore, the prepared CoNiS x -CN composite exhibited a dramatic photocatalytic HER performance of 2.366 μmol mg–1 h–1, which is about 76-fold higher in comparison with pristine g-C3N4 and comparable to g-C3N4 with Pt as a cocatalyst under 420 nm light irradiation. This study reveals a promising and efficient bimetallic cocatalyst for the photocatalytic H2 evolution reaction.
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•The nanostructured nitrogen-doped La2Ti2O7 was successfully synthesized.•The high degree of nitrogen doping was accomplished by the sophisticated synthesis.•The nanostructurization ...and the nitrogen-doping enhanced photocatalytic activity.•Triethanolamine played important roles in the synthesis of nitrogen-doped La2Ti2O7.•The particle size of La2Ti2O7 was much smaller than that of the conventional ones.
A series of N-doped La2Ti2O7 nanocrystal for photocatalytic NOx oxidation are successfully prepared by a two-steps process including hydrothermal reaction and heat treatment under NH3 flow. The effects of different nitrogen doping amounts on the structure, optical property and photocatalytic activity of the obtained N-doped La2Ti2O7 are investigated. The photocatalytic activity and stability of the N-doped La2Ti2O7 samples are evaluated through photocatalytic oxidation of NOx under UV and visible light irradiation. The nanosheet morphology of N-doped La2Ti2O7 is originated from La2Ti2O7 precursor synthesized by hydrothermal reaction. The addition of triethanolamine (TEA) in the hydrothermal reaction largely affects the morphology of La2Ti2O7 to form nanocrystal. The light absorption of La2Ti2O7 nanocrystal is cut off at 338 nm, while the N-doped La2Ti2O7 nanocrystals exhibit the extended light absorption up to 560 nm. It is found that the N doping into La2Ti2O7 enhances absorption in the visible light region to exhibit higher activity for photocatalytic oxidation of NO gas. The optimized N-doped La2Ti2O7 nanocrystal with 4.79 at% of nitrogen dopant possesses the best photocatalytic NOx oxidation activity under both ultraviolet and visible light irradiation compared with N-doped La2Ti2O7 samples obtained by hydrothermal reaction without TEA or flux synthesis of La2Ti2O7 and the subsequent treatment with NH3. The enhancement of photocatalytic activity should originate from simultaneous achievement of large specific surface area and strong visible light absorption due to the large amount of nitrogen dopants.
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