Latest ArticlesAs an important component of the atmosphere, ammonia (NH3) plays a very important role in maintaining the balance of environment. However, it is also one of the most toxic gases that can cause damage to the human respiratory system and mucous membranes even at low concentrations. As such, development of highly sensitive and selective NH3 sensors is of high significance for environmental monitoring and health maintenance. Herein, we have synthesized Au@Ag@AgCl core-shell nanoparticles (NPs) by oxidative etching and precipitating Au@Ag core-shell NPs using FeCl3 and further used them as optical probes for the colorimetric detection of NH3. The sensing mechanism is based on the fact that the etching of NH3 on AgCl and Ag shell leads to the variations of ingredients and core-to-shell ratio of the Au@Ag@AgCl NPs, thereby inducing noticeable spectral and color changes. By replacing the outmost layer of Ag with AgCl, not only is the stability of the sensor against oxygen significantly enhanced, but also is the sensitivity of the method improved. The method exhibits good linear relationship for the detection of NH3 from 0 to 5000 μmol/L with the limit of detection of 6.4 μmol/L. This method was successfully applied to the detection of simulated air polluted by NH3, indicating its practical applicability for environmental monitoring. This method shows great potential for on-site NH3 detection particularly in remote area, where a simple, fast, low-cost, and easy-to-handle method is highly desirable.
MXenes are a group of recently discovered 2D materials and have attracted extensive attention since their first report in 2011; they have shown excellent prospects for energy storage applications owing to their unique layered microstructure and tunable electrical properties. One major feature of MXenes is their tailorable surface terminations (e.g., −F, −O, −OH). Numerous studies have indicated that the composition of the surface terminations can significantly impact the electrochemical properties of MXenes. Nonetheless, the underlying mechanisms are still poorly understood, mainly because of the difficulties in quantitative analysis and characterization. This review summarizes the latest research progress on MXene terminations. First, a systematic introduction to the approaches for preparing MXenes is presented, which generally dominates the surface terminations. Then, theoretical and experimental efforts regarding the surface terminations are discussed, and the influence of surface terminations on the electronic and electrochemical properties of MXenes are generalized. Finally, we present the significance and research prospects of MXene terminations. We expect this review to encourage research on MXenes and provide guidance for usingthese materials for batteries and supercapacitors.
As a kind of environmentally benign reagents, α-keto acids have been extensively employed as key starting materials in organic synthesis. Organic electrosynthesis has the advantages of reducing byproduct generation, improving the cost-efficiency of synthetic processes, and accessing reactive intermediates under mild conditions. Inspired by the merits of organic electrosynthesis, α-keto acids have shown many synthetic applications in electrochemical acylation, cyclization, and reductive amination reactions with improved efficiencies and selectivities. This review covers the recent breakthroughs achieved in the electrochemical transformations of α-keto acids, aimed at highlighting these electrochemical reactions' features and mechanistic rationalisations. Meanwhile, the practicalities and limitations of these transformations are also presented where possible.
A mesoporous cobalt aluminate (CoAl2O4) spinel is synthesized through a combustion method and adopted for the activation of peroxymonosulfate (PMS) to degrade organic pollutants. Multiple characterization procedures are conducted to investigate the morphology and physicochemical properties of the CoAl2O4 spinel. Due to its mesoporous structure, large surface area, and high electrical conductivity, the obtained CoAl2O4 exhibits remarkable catalytic activity for Rhodamine B (RhB) degradation. Its RhB degradation rate is 89.0 and 10.5 times greater than those of Co3O4 and CoAl2O4 spinel prepared by a precipitation method, respectively. Moreover, the mesoporous CoAl2O4 spinel demonstrates a broad operating pH range and excellent recyclability. The influence of several parameters (catalyst amount, PMS concentration, initial pH, and coexisting inorganic anions) on the oxidation of RhB is evaluated. Through quenching tests and electron paramagnetic resonance experiments, sulfate radicals are identified as the predominant reactive species in RhB degradation. This paper provides new insights for the development of efficient, stable, and reusable cobalt-based heterogeneous catalysts and promotes the application of persulfate activation technology for the treatment of refractory organic wastewater.
Selenium doped carbon (Se/C), an easily fabricated material, was found to be bio-active and it can serve as an adjuvant to enhance the immune effect of Tween 80/Brij 30 (T80/B30) vesicles and Tween 80/polymer cationic surfactant PN320 (T80/PN320) mixed micelles. The synergistic effect of the combination of T80/B30 vesicles and T80/PN320 mixed micelles with Se/C on nasal mucosal immunity was studied in this work, which might provide theoretical basis for developing the related new adjuvant for nasal immunization of recombinant protein, peptide and split protein vaccine. Since both selenium and carbon were bio-compatible elements, Se/C might be safe for practical applications, and this was also reflected by the low hemolytic activity of the materials. This work not only reports an efficient protocol for adjuvant development, but also significantly expands the application scope of selenium chemistry.
With high catalytic activity and stability, nanozymes have huge advantage in generating or eliminating the reactive oxygen species (ROS) due to their intrinsic enzyme-mimicking abilities, therefore attracting wide attention in ROS-related disease therapy. To better design nanozyme-based platforms for ROS-related biological application, we firstly illustrate the catalytic mechanism of different activities, and then introduce different strategies for using nanozymes to augment or reduce ROS level for the applications in cancer therapy, pathogen infection, neurodegeneration, etc. Finally, the challenges and future opportunities are proposed for the development and application of nanozymes.
Porous organic frameworks (POFs) are excellently stable porous materials, which can be employed as host platforms to support metal nanoparticles as functional composites for various applications. Herein, a novel POF is successfully prepared via Friedel-Crafts reaction. Silver nanoparticles (Ag NPs) are embedded in the prepared POF to generate an Ag@POF composite, which not only possesses high surface area, outstanding physicochemical stability and outstretched π-conjugation skeleton, but also exhibits preferable electrochemical stability and conductivity. This composite is able to immobilize a mass of aptamer strands to fabricate an intriguing electrochemical aptasensor. Electrochemical impedance spectroscopy (EIS) is a commonly used technology to analyze the electrochemical signal variation. The Ag@POF-based biosensor shows the excellent electrochemical detection behavior through analyzing EIS. For instance theophylline as a research mode, the Ag@POF based electrochemical aptasensor reveals ultra-sensitiveness, high selectivity, remarkable stability, good repeatability and simple operability even in various real samples. Notably, this aptasensor has the sensitive detection performance with the limit of detection of 0.191 pg/mL (1.06 pmol/L) in a wide concentration range of 5.0 × 10-4 – 5.0 ng/mL (2.78 × 10-3 – 27.8 nmol/L).
Pressure-related sensing materials in mechanochromic luminescent materials have received wide attention. However, at present, most piezochromic luminescence (PCL) materials have problems such as aggregation-caused quenching (ACQ) effect due to the presence of powder form, complicated preparation methods and fluorescence quenching effect under high pressure. To solve these problems, we employ three components containing carbon dots (CDs), layered double hydroxides (LDHs) and polyvinyl alcohol (PVA) to construct the CDs-LDHs/PVA film. The LDHs can provide a rigid environment for CDs and improve the luminescent efficiency of CDs. The film shows high sensitivity, stability and reversibility. Moreover, the compressed film can recover to its original state by heating. Therefore, the PCL film with dual emission (fluorescence and phosphorescence) characteristic is constructed, which boosts the sensitivity of pressure-sensing.
Electrochemical overall water splitting is attracting a broad focus as a promising strategy for converting the electrical output of renewable resources into chemical fuels, specifically oxygen and hydrogen. However, the urgent challenge in water electrolysis is to search for low-cost, high-efficiency catalysts based on earth-abundant elements as an alternative to the high-cost but effective noble metal-based catalysts. The transition metal-based catalysts are more appealing than the noble metal catalysts because of its low cost, high performance and long stability. Some recent advances for the development in overall water splitting are reviewed in terms of transition metal-based oxides, carbides, phosphides, sulfides, and hybrids of their mixtures as hybrid bifunctional electrocatalysts. Concentrating on different catalytic mechanisms, recent advances in their structural design, controllable synthesis, mechanistic insight, and performance-enhancing strategies are proposed. The challenges and prospects for the future development of transition metal-based bifunctional electrocatalysts are also addressed.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
