Latest ArticlesIntroducing ligand into the surface of gold (Au)-based catalyst has been recognized as an efficient strategy to enhance the performance of catalyst in acetylene hydrochlorination reaction. However, due to the multifactorial deactivation, the usage of single type of ligand has limitations on the performance improvement. In this work, two types of ligands including a molecular 2-methylimidazole and an ionic cetrimonium are selected to protect Aun+ species. After kinetics analysis, advanced characterization, and density functional theory simulation, we demonstrate the optimal interaction model between two ligands and Au species: Two 2-methylimidazole molecules are coordinated with high-valent Au species while cetrimonium is interacted via electrostatic interaction. Except the synergistic effect in the decrease of Au species reduction and agglomeration, the existence of molecular ligand greatly increases the adsorption of hydrogen chloride while the ionic ligand significantly inhibits the deposition of coke. Due to the positive effect of dual-ligands, we achieved 97.1% of acetylene conversion and 0.29 h−1 of deactivation rate under high gas hourly space velocity of acetylene. This work establishes a foundation to explore the property-activity relationships in Au-based catalyst via ligand engineering.
It has been challenging for Fe(Ⅲ) regeneration in Fe-based photocatalysts for continuous peroxydisulfate (PDS) activation due to the lower ability to reduce Fe(Ⅲ). In this work, Fe-doped ultrathin VO2 (Fe-VO2) nanobelts were synthesized for purifying metronidazole (MNZ) via PDS activation. As an efficient Fenton-like catalyst for PDS activation, 2 wt% Fe-doped VO2 can remove 98% of MNZ within 40 min and exhibits impressive recyclability. The synergistic effect of Fe-VO2 and Fe(Ⅲ) activated PDS boosted the photocatalytic performance. Moreover, SO4•−, h+, O2•−, 1O2, and •OH were the main reactive radicals. The effects of initial MNZ concentration, Fe-VO2, PDS dosage, and various anions/cations on MNZ removal by the Fe-VO2/PDS/Vis system were studied. The intermediates of MNZ degradation and possible pathways were determined by density function theory (DFT) calculations and HPLC-MS. This study provided a sustainable technology using Fe-doped ultrathin VO2 nanobelts for photocatalytic PDS activation and decontamination of pharmaceutical wastewater.
Bacterial infections have always been a major threat to human health. Skin wounds are frequently exposed to the external environment, and they may become contaminated by bacteria derived from the surrounding skin, the local environment, and the patient's own endogenous sources. Contaminated wounds may enter a state of chronic inflammation that impedes healing. Urgent development of antibacterial wound dressings capable of effectively combating bacteria and overcoming resistance is necessary. Nanotechnology and nanomaterials present promising potential as innovative strategies for antimicrobial wound dressings, owing to their robust antibacterial characteristics and the inherent advantage of avoiding antibiotic resistance. Therefore, this review provides a concise overview of the antimicrobial mechanisms exhibited by low-dimensional nanomaterials. It further categorizes common low-dimensional antimicrobial nanomaterials into zero-dimensional (0D), one-dimensional (1D) and two-dimensional (2D) nanomaterials based on their structural characteristics, and gives a detailed compendium of the latest research advances and applications of different low-dimensional antimicrobial nanomaterials in wound healing, which could be helpful for the development of more effective wound dressings.
Although lots of efforts have been devoted on new less hygroscopic dopants to address problems in hole transport materials (HTM), the long-time post-oxidation and the volatilization of 4-tert-butylpyridine (tBP) are still issues. A new doping mechanism for spiro-OMeTAD by disulfiram (TETD) is revealed in this work. Owing to its disulfide bond, TETD can be activated easily to produce reactive sulfur for the rapid oxidation of spiro-OMeTAD in the absence of oxygen with formation of [spiro-OMeTAD•]+[SC(S)N(C2H5)2]-. Thus, in this situation, the Li+ ion has the opportunity to coordinate tBP and fix each other in HTM film. DFT calculations suggest that the resulting favorable energy (with a ΔE of −1.29 eV) must come from the mutual interactions among Li+, TFSI−, and tBP, which is different from the well-known doping process that tBP would not participate in the doping reaction. As a result, the introduction of a new radical into the HTM greatly reduce device performance fluctuations due to the environmental dependence and inhibit tBP volatilizing for enhanced long-term stability.
In contrast to research on active sites in nanomaterials, lithium tantalate single crystals, known for their exceptional optical properties and long-range ordered lattice structure, present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry. Typically, the isotropy of a specific facet provides a perfect support for studying heteroatom doping. Herein, this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals. The presence of iron not only modifies the electronic structure of lithium tantalate, improving its light absorption capacity, but also functions as an active site for the nitrogen adsorption and activation. The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95 µg cm−2 h−1, which is three times higher than that of undoped lithium tantalate. The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating. This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.
As hydrogen energy technologies gain momentum, the role of renewable energy in facilitating sustainable hydrogen production is becoming increasingly critical. As a hydrogen production method, water electrolysis has attracted much attention from researchers due to its operational simplicity, the high purity of the hydrogen generated, and its potential for achieving zero carbon emissions throughout the process. Numerous studies has been manipulated on platinum (Pt)-based catalysts, which exhibit superior performance in hydrogen evolution reactions. Within this category, Pt nanoclusters stand out due to their unique attributes, such as quantum size effects and unique coordination environments. These features enable them to outperform both Pt metal atoms and nanoparticles in hydrogen evolution reactions regarding activity and stability. Here, we primarily delve into the reaction mechanisms underlying Pt nanocluster-based hydrogen catalysts, with particular emphasis on the interactions between the metal catalysts and their associated support materials. We provide an exhaustive summary of the strategies employed in the synthesis, the structural analyses conducted, and the performance metrics observed for Pt nanocluster catalysts when paired with various supporting materials. In closing, we explore the future potential and challenges facing Pt nanocluster-based catalysts in the context of industrial water electrolysis, along with emerging avenues for their design and optimization.
Ultrafast reaction kinetics is essential for rapid detection, synthesis, and process monitoring, but the intrinsic energy barrier as a basic material property is challenging to tailor. With the involvement of nanointerfacial chemistry, we propose a carbonization-based strategy for achieving ultrafast chemical reaction. In a case study, ultrafast Griess reaction within 1 min through the carbonization of N-(1-naphthalene)ethylenediamine (NETH) was realized. The carbonization-mediated ultrafast reaction is attributed to the synergic action of reduced electrostatic repulsion, enriched reactant concentration, and boosted NETH nucleophilicity. The enhanced reaction kinetics in o-phenylenediamine-Cu2+ and o-phenylenediamine-ascorbic acid systems validate the universality of carbonization-engineered ultrafast chemical reaction strategy. The finding of this work offers a novel and simple tactic for the fabrication of multifunctional nanoparticles as ultrafast and effective nanoreactants and/or reporters in analytical, biological, and material aspects.
Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries (LIBs), but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application. Herein, from a new perspective, a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth (CC/Ni), which endows the supported active materials with exceptional electronic conductivity and structural stability. In addition, the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components, ensuring the structural integrity of electrodes upon cycling. More importantly, the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions. Therefore, taking Ni3S2 nanosheet (Ni3S2 NS) anode as an example, the prepared Ni3S2 NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm2 at 1 mA/cm2 and high capacity retention of 1.68 mAh/cm2 at a high rate of 8 mA/cm2. This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.
Chemical investigation of the marine-derived fungus Chaetomium globosum HBU-45 led to the discovery of chaeglobol A (1). Its structure was determined by spectroscopic analysis, computational electronic circular dichroism (ECD)/optical rotatory dispersion (ORD) methods, and X-ray crystallography. Compound 1 represents a new skeleton with an uncommon 6/6/6/5/6/5/6/5 octacyclic system, which is presumably biosynthesized via a [4 + 2] cycloaddition and an enzymatic cyclization. Chaeglobol A (1) exhibited inhibitory activity against B. dothidea by destroying cell membrane integrity and causing oxidative damage within the cells.
Iron-porphyrin metal-organic frameworks (MOFs) have emerged as a remarkable class of semiconductors with adjustable photoelectrical properties and peroxidase-mimicking activities, yet their full potential remains largely unexplored. The organic photoelectrochemical transistor (OPECT) has been proven to be a prominent platform for diverse applications. Herein, iron-porphyrin MOFs, as bifunctional photo-gating module and horseradish peroxidase-mimicking nanozyme, is explored for novel OPECT bioanalysis. Exemplified by alpha-fetoprotein (AFP)-dependent sandwich immunorecognition and therein glucose oxidase (GOx)-generated H2O2 to etch CdS quantum dots on the surface of iron-porphyrin MOFs, this OPECT bioanalysis achieved high-performance AFP detection with a low detection limit of 24 fg/mL. This work featured a bifunctional iron-porphyrin MOFs gated OPECT, which is envisioned to inspire more interest in developing the diverse MOFs-nanozymes toward novel optoelectronics and beyond.
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