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Journal of Colloid and Interface Science Jun 2024The CO preferential oxidation reaction (CO-PROX) is an effective strategy to remove residual poisonous CO in proton exchange membrane fuel cells, in which oxygen...
The CO preferential oxidation reaction (CO-PROX) is an effective strategy to remove residual poisonous CO in proton exchange membrane fuel cells, in which oxygen vacancies play a critical role in CO adsorption and activation. Herein, a series of CuO/CeO catalysts derived from Ce-MOFs precursors were synthesized using different organic ligands via the hydrothermal method and the CO-PROX performance was investigated. The CuO/CeO-135 catalyst derived from homophthalic tricarboxylic acid (1,3,5-HBTC) exhibited superior catalytic performance with 100 % CO conversion at a relatively low temperature (T = 100 °C), with a wide reaction temperature range and excellent stability. The superior catalytic properties were attributed to the structural improvements provided by the 1,3,5-HBTC precursors and the promotional effects of oxygen vacancies. Additionally, in-situ Raman spectroscopy was performed to verify the dynamic roles of oxygen vacancies for CO adsorption and activation, while in-situ DRIFTS analysis revealed key intermediates in the CO-PROX reaction, shedding light on the mechanistic aspects of the catalytic process. This work not only demonstrates insights into the effective CuO/CeO catalysts for CO preferential oxidation, but also provides a feasible way to synthesize MOF-derived catalysts.
PubMed: 38955009
DOI: 10.1016/j.jcis.2024.06.110 -
Chembiochem : a European Journal of... Jul 2024Curcumin is a bright yellow naturally occurring polyphenol which is the principal component of turmeric. It is used as herbal supplement, cosmetics ingredient, and food...
Curcumin is a bright yellow naturally occurring polyphenol which is the principal component of turmeric. It is used as herbal supplement, cosmetics ingredient, and food coloring agent. Over the years, the therapeutic properties of natural product curcumin have gone unexploited but not unnoticed. Curcumin cannot be employed as a drug due to limitations such as low aqueous solubility and limited bioavailability. Many attempts have been made to overcome these limitations by confining the drug in various confined media to enhance its bioavailability. The biomolecule is emissive and undergoes fundamental excited state processes such as solvation dynamics and excited state intramolecular proton transfer (ESIPT). Curcumin based biomaterials and nanomaterials are also a fast advancing field where curcumin is an intrinsic component necessary for formation of these materials and no longer added as an external free drug. In this review, we will summarise the recent research on the photophysical and photochemical properties of curcumin and its excited state dynamics in various bio-mimicking systems. At the same time we wish to also incorporate the various applications of curcumin, especially in biology. Lastly due to the growing importance of materials science, we will briefly discuss some recent advances on curcumin based biomaterials and nanomaterials.
PubMed: 38954727
DOI: 10.1002/cbic.202400335 -
Methods in Molecular Biology (Clifton,... 2024Eukaryotic cells have been constantly challenged throughout their evolution by pathogens, mechanical stresses, or toxic compounds that induce plasma membrane (PM) or...
Eukaryotic cells have been constantly challenged throughout their evolution by pathogens, mechanical stresses, or toxic compounds that induce plasma membrane (PM) or endolysosomal membrane damage. The survival of the wounded cells depends on damage detection and repair machineries that are evolutionary conserved between protozoan, plants, and animals. We use the social amoeba Dictyostelium discoideum as a model system to study bacteria, mechanical or sterile membrane damage that allows us to identify and monitor factors involved in PM, endolysosomal damage response (ELDR), and endolysosomal homeostasis. Importantly, the sterile damage techniques presented here homogenously affect cell populations, which allows to phenotype mutant strains and quantify various aspects of cell fitness using live cell microscopy. This is instrumental to functionally assess genes involved in the repair of damaged plasma membrane or intracellular compartments and the degradation of extensively damaged compartments. Here, we describe how to inflict sterile PM or endolysosomal membrane damage, how to monitor the cell-intrinsic response to damage, and how to proxy proton leakage from damaged acidic compartments and quantify cell viability.
Topics: Dictyostelium; Cell Membrane; Lysosomes; Cell Survival
PubMed: 38954196
DOI: 10.1007/978-1-0716-3894-1_3 -
ChemSusChem Jul 2024Due to the active unstable nature of carbon anions, it is challenging to develop carbanion-functionalized ionic liquids (ILs) for efficient and reversible carbon dioxide...
Due to the active unstable nature of carbon anions, it is challenging to develop carbanion-functionalized ionic liquids (ILs) for efficient and reversible carbon dioxide (CO2) capture. Here, a series of carbanion-based ILs with large conjugated structures were designed and a promising system was achieved through tuning the nucleophilicity of carbanions and screening the cation. The ideal carbanion-functionalized IL trihexyl(tetradecyl)phosphonium N,N-diethycyanoacetoamide ([P66614][DECA]) showed equimolar chemisorption of CO2 (up to 0.98 mol CO2 /mol IL) under ambient pressure and excellent absorption rate. What's more, the combined CO2 can be released easily, leading to excellent reversibility due to high stability of anion conjugated structures. More importantly, the presence of water had negligible effect on the absorption capacity, which makes it potential to be applied to the CO2 capture in industrial flue gas. The chemisorption mechanism of the carbanion and CO2 was confirmed by spectroscopic investigations and DFT calculations, where carboxylic acid product was formed through proton transfer after the carbanions reacted with CO2. Considering that high capacity, quick rate as well as excellent reversibility, these carbanion-functionalized IL should certainly represent competitive candidates for further scale up and practical application in CO2 capture.
PubMed: 38954154
DOI: 10.1002/cssc.202401111 -
Angewandte Chemie (International Ed. in... Jul 2024Proton batteries have attracted increasing interests because of their potential for grid-scale energy storage with high safety and great low-temperature performances....
Proton batteries have attracted increasing interests because of their potential for grid-scale energy storage with high safety and great low-temperature performances. However, their development is significantly retarded by electrolyte design due to free water corrosion. Herein, we report a layer intercalatable electrolyte (LIE) by introducing trimethyl phosphate (TMP) into traditional acidic electrolyte. Different from conventional role in batteries, the presence of TMP intriguingly achieves co-intercalation of solvent molecules into the interlayer of anode materials, enabling a new working mechanism for proton reactions. The electrode corrosion was also strongly retarded with expanded electrochemical stability window. The half-cell therefore showed an outstanding long-term cycling stability with 91.0% capacity retention at 5 A g-1 after 5000 cycles. Furthermore, the assembled full batteries can even deliver an ultra-long lifetime with a capacity retention of 74.9% for 2 months running at -20 °C. This work provides new opportunities for electrolyte design of aqueous batteries.
PubMed: 38953787
DOI: 10.1002/anie.202409871 -
NMR in Biomedicine Jul 2024Proton MRS is used clinically to collect localized, quantitative metabolic data from living tissues. However, the presence of baselines in the spectra complicates...
Proton MRS is used clinically to collect localized, quantitative metabolic data from living tissues. However, the presence of baselines in the spectra complicates accurate MRS data quantification. The occurrence of baselines is not specific to short-echo-time MRS data. In short-echo-time MRS, the baseline consists typically of a dominating macromolecular (MM) part, and can, depending on B shimming, poor voxel placement, and/or localization sequences, also contain broad water and lipid resonance components, indicated by broad components (BCs). In long-echo-time MRS, the MM part is usually much smaller, but BCs may still be present. The sum of MM and BCs is denoted by the baseline. Many algorithms have been proposed over the years to tackle these artefacts. A first approach is to identify the baseline itself in a preprocessing step, and a second approach is to model the baseline in the quantification of the MRS data themselves. This paper gives an overview of baseline handling algorithms and also proposes a new algorithm for baseline correction. A subset of suitable baseline removal algorithms were tested on in vivo MRSI data (semi-LASER at T = 40 ms) and compared with the new algorithm. The baselines in all datasets were removed using the different methods and subsequently fitted using spectrIm-QMRS with a TDFDFit fitting model that contained only a metabolite basis set and lacked a baseline model. The same spectra were also fitted using a spectrIm-QMRS model that explicitly models the metabolites and the baseline of the spectrum. The quantification results of the latter quantification were regarded as ground truth. The fit quality number (FQN) was used to assess baseline removal effectiveness, and correlations between metabolite peak areas and ground truth models were also examined. The results show a competitive performance of our new proposed algorithm, underscoring its automatic approach and efficiency. Nevertheless, none of the tested baseline correction methods achieved FQNs as good as the ground truth model. All separately applied baseline correction methods introduce a bias in the observed metabolite peak areas. We conclude that all baseline correction methods tested, when applied as a separate preprocessing step, yield poorer FQNs and biased quantification results. While they may enhance visual display, they are not advisable for use before spectral fitting.
PubMed: 38953695
DOI: 10.1002/nbm.5203 -
Environmental Science & Technology Jul 2024Electroreduction of nitrate (NORR) to ammonia in membraneless electrolyzers is of great significance for reducing the cost and saving energy consumption. However, severe...
Electroreduction of nitrate (NORR) to ammonia in membraneless electrolyzers is of great significance for reducing the cost and saving energy consumption. However, severe chemical crossover with side reactions makes it challenging to achieve ideal electrolysis. Herein, we propose a general strategy for efficient membraneless ammonia synthesis by screening NORR catalysts with inferior oxygen reduction activity and matching the counter electrode (CE) with good oxygen evolution activity while blocking anodic ammonia oxidation. Consequently, screening the available Co-Co system, the membraneless NO-to-NH conversion performance was significantly higher than H-type cells using costly proton-exchange membranes. At 200 mA cm, the full-cell voltage of the membraneless system (∼2.5 V) is 4 V lower than that of the membrane system (∼6.5 V), and the savings are 61.4 kW h (or 56.9%) per 1 kg NH produced. A well-designed pulse process, inducing reversible surface reconstruction that in situ generates and restores the active Co(III) species at the working electrode and forms favorable CoO/CoOOH at the CE, further significantly improves NO-to-NH conversion and blocks side reactions. A maximum NH yield rate of 1500.9 μmol cm h was achieved at -0.9 V (Faraday efficiency 92.6%). This pulse-coupled membraneless strategy provides new insights into design complex electrochemical synthesis.
PubMed: 38953681
DOI: 10.1021/acs.est.4c02445 -
The Journal of Physical Chemistry. B Jul 2024Specific ion effects in the interactions of monovalent anions with amine groups─one of the hydrophilic moieties found in proteins─were investigated using...
Specific ion effects in the interactions of monovalent anions with amine groups─one of the hydrophilic moieties found in proteins─were investigated using octadecylamine monolayers floating at air-aqueous solution interfaces. We find that at solution pH 5.7, larger monovalent anions induce a nonzero pressure starting at higher areas/molecules, i.e., a wider "liquid expanded" region in the monolayer isotherms. Using X-ray fluorescence at near total reflection (XFNTR), an element- and surface-specific technique, ion adsorption to the amines at pH 5.7 is confirmed to be ion-specific and to follow the conventional Hofmeister series. However, at pH 4, this ion specificity is no longer observed. We propose that at the higher pH, the amine headgroups are only partially protonated, and large polarizable ions such as iodine are better able to boost amine protonation. At the lower pH, on the other hand, the monolayer is fully protonated, and electrostatic interactions dominate over ion specificity. These results demonstrate that ion specificity can be modified by changing the experimental conditions.
PubMed: 38953612
DOI: 10.1021/acs.jpcb.4c02359 -
Chemistry (Weinheim An Der Bergstrasse,... Jul 2024This paper presents the synthesis and characterization of a series of novel monomeric aqua-ligated iron(III) complexes, [FeIII(L5R)(OH2)]2+ (R = OMe, H, Cl, NO2),...
This paper presents the synthesis and characterization of a series of novel monomeric aqua-ligated iron(III) complexes, [FeIII(L5R)(OH2)]2+ (R = OMe, H, Cl, NO2), supported by an amide-containing pentadentate N5 donor ligand, L5R [HL5R = 2-(((1-methyl-1H-imidazol-2-yl)methyl)(pyridin-2-yl-methyl)amino)-N-(5-R-quinolin-8-yl)acetamide]. The complexes were characterized by various spectroscopic and analytical techniques, including electrochemistry and magnetic measurements. The Fe(III)-hydroxo complexes, [FeIII(L5R)(OH)]1+, were generated in situ by deprotonating the corresponding aqua complexes in a pH ~7 aqueous medium. In another way, adding one equivalent of a base to a methanolic solution of the Fe(III)-aqua complexes also produced the Fe(III)-hydroxo complexes. The study uses linoleic fatty acid as a substrate to explore the hydrogen atom abstraction (HAA) reactivity of both hydroxo- and aqua-complexes. The investigation highlights the substitution effect of the L5R ligand on reactivity, revealing a higher rate when an electron-withdrawing group is present. Hammett analyses and(or) determination of the asynchronicity factor (η) suggest an oxidative asynchronous concerted proton-electron transfer (CPET) pathway for the HAA reactions. Aqua complexes exhibited a higher asynchronicity in CPET, resulting in higher reaction rates than their hydroxo analogues. Overall, the work provides insights into the beneficial role of a higher imbalance in electron-transfer-proton-transfer (ET-PT) contributions in HAA reactivity.
PubMed: 38953593
DOI: 10.1002/chem.202401163 -
Chemistry (Weinheim An Der Bergstrasse,... Jul 2024Anion exchange membrane fuel cell (AEMFC) is an emerging and promising technology that can help realize a carbon-neutral, sustainable economy. Also, compared to the...
Anion exchange membrane fuel cell (AEMFC) is an emerging and promising technology that can help realize a carbon-neutral, sustainable economy. Also, compared to the proton exchange membrane counterpart, AEMFC can achieve comparable cell outputs with lower costs due to the applicability of non-platinum group metal electrocatalysts for the reaction on the electrodes' surfaces. However, the wide application of the AEMFCs has been impeded by the unsatisfactory stability and performance of the hydroxide-conductive membranes in the past. Recently researchers have made breakthroughs using polyarylene (PA)-based AEMs. This article summarizes the recent advances of a class of AEMs with aromatic backbone without ether bonds, mainly synthesized by Friedel-Crafts polycondensation. Such PA-based AEMs showed high chemical/mechanical stabilities and ionic conductivity, and even the fuel cell with those AEMs showed impressive peak power density of up to 2.58 W cm. In this concept article, we classify major strategies for making PA-based AEMs to show the recent trends, highlight synthesis, characterization, and properties, and provide a brief outlook.
PubMed: 38953321
DOI: 10.1002/chem.202401208