Latest ArticlesIt is always highly pursued to develop efficient and durable catalysts for catalytic applications. Herein, intermetallic PdBi aerogels with tunable activity were prepared successfully via a surfactant-free spontaneous gelation process. The prepared PdBi aerogels have a three-dimensional high porous structure and plentiful active sites pervaded on the ultrathin interlinked nanowires network. These unique structures, as well as the synergistic effect between Pd and Bi, can accelerate mass and electron transfer, and improve the atom utilization ratio of Pd atoms to promote the catalytic efficiency. As a proof-of-concept application, the optimized Pd2Bi1 aerogels exhibit 4.2 and 6.2 times higher catalytic activity for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB) than those of commercial Pd/C, respectively. With the introduction of non-noble metal of Bi, the cost of the resulted PdBi aerogels can be dropped significantly while the catalytic capability of PdBi aerogel will be improved sharply. This strategy will bring good hints to rationally design fine catalysts for various applications.
Photocatalysis and Fenton process are two primary and promising advanced oxidation processes to degrade organic pollutants. However, the practical applications of single photocatalysis and Fenton process are still limited. Introducing one of them into another to form a combined photocatalytic Fenton-like system has shown great potential but still faces challenges in designing a well-tailored catalyst. Herein, a confined photocatalytic Fenton-like micro-reactor catalyst with a movable Fe3O4 core and a mesoporous TiO2 shell has been constructed via a successive Stöber coating strategy, followed by an ultrasound assisted etching method. The resulting micro-reactor possesses well-defined yolk-shell structures with uniform mesopores (~4 nm), a large Brunauer-Emmett-Teller (BET) surface area (~166.7 m2/g), a high pore volume (~0.56 cm3/g) and a strong magnetization (~51 emu/g), as well as tunable reactor sizes (20−90 nm). When evaluated for degrading bisphenol A under solar light in the presence of peroxymonosulfate, the micro-reactor exhibits a superior catalytic degradation performance with a high magnetic separation efficiency and an excellent recycle ability. The outstanding performance can be attributed to its unique textual structure, which leads to a great synergistic effect from the photocatalytic and Fenton-like process. This study gives an important insight into the design and synthesis of an advanced micro-reactor for a combined advanced oxidation processes (AOPs).
Aflatoxin B1 (AFB1) is one of the most toxic, mutagenic and carcinogenic mycotoxin, widely exists in contaminated food, grains and feedstuff products. In this study, a novel magnetic beads multicolor colorimetric immunoassay (MBMCIA) based on Au@Ag nanorods (Au@Ag NRs) is proposed to visual detect ultralow concentration of AFB1 with high-resolution by the naked-eye. To design the MBMCIA system, AFB1-BSA conjugates were first coated on the surface of magnetic beads (MBs), then alkaline phosphatase (ALP) as a bridge between immunoassay and color reaction was used for catalytic hydrolysis of ascorbic acid-phosphate to generate reductive ascorbic acid. Finally, the yielded ascorbic acid could reduce silver ions to grow a silver coating on the surface of gold nanorods to generate Au@Ag NRs, which leads to the bule-shifted longitudinal absorption peak of Au NRs, accompanying with a series of perceptible color change. Under the optimal conditions, the proposed MBMCIA exhibited good sensitivity and specificity for the detection of AFB1 with the detection limit as low as 5.7 pg/mL. Meanwhile, the MBMCIA was also applied for the analysis of AFB1 in spiked wheat samples, the obtained recoveries range from 99.1% to 104.3% with relative standard deviation (RSD) less than 7.05% were acceptable. The proposed MBMCIA integrates separated, enriched, anti-interference and signal read-out into one, which opens up a new avenue for an on-site visual food safety inspection or environmental monitoring.
Cytochrome P450 OleTSA, a new cytochrome P450 enzyme from Staphylococcus aureus, catalyzes the oxidative decarboxylation and hydroxylation of fatty acids to generate terminal alkenes and fatty alcohols. The mechanism of this bifurcative chemistry remains largely unknown. Herein, a class of derivatized fatty acids were synthesized as probes to investigate the effects of substrate structure on the product type of P450 OleTSA. The results demonstrate that the fine-tuned structure of substrates, even in a remote distance from the carboxyl group, significantly regulates OleT catalyzed decarboxylation/hydroxylation reactions. Molecular docking analysis indicated the potential interactions between the carboxylate groups of different probes and the enzyme active center which was attributed to the bifurcative chemistry.
The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for green-power production and sustainable development. Cellulase is the core component in the saccharification process. Simple and efficient assay method to determine cellulase activity in saccharification is thus highly required. In this work, a boronate-affinity surface based renewable and ultrasensitive electrochemical sensor for cellulase activity determination has been fabricated. Through boronate-sugar interaction, celluloses are attached to the electrode surface, forming the cellulose nano-network at the sensing interface. Cellulase degradation can lead to the variation of electrochemical impedance. Thus, electrochemical impedance signal can reflect the cellulase activity. Importantly, via fully utilizing the boronate-affinity chemistry that enables reversible fabrication of cellulose nano-network, a renewable sensing surface has been firstly constructed for cellulase activity assay. Thanks to interfacial diffusion process of electrochemical sensor, the product inhibitory effect in the cellulase activity assays can be circumvented. The proposed electrochemical sensor is ultrasensitive for label-free cellulase activity detection with a very simple fabrication process, showing great potential for activity screen of new enzymes in saccharification conversion.
To search naturally occurring interleukin-1β (IL-1β) inhibitors, biscaesalmins A (1) and B (2), two highly oxidized dimeric cassane diterpenoids with a newly formed alicyclic skeleton, have been isolated from the traditional Chinese medicine Kushilian (Caesalpinia minax). Their full structures were determined by comprehensive spectroscopic analysis and quantum chemical TD-DFT (time-dependent density functional theory) calculation. Biosynthetically, 1 and 2 were formed via an intermolecular [4+2] Diels-Alder cycloaddition of two monomers, affording an additional six-membered carbon ring linkage. Compounds 1 and 2 inhibited nitric oxide production on lipopolysaccharide-stimulated THP-1 macrophages, with IC50 values being at 1.20±0.23 and 2.30±0.15 μmol/L, respectively. Furthermore, compound 1 inhibited NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome-mediated IL-1β production and blocked the migration of macrophages towards adipocyte conditioned medium. Biscaesalmins A and B might be candidates for treating inflammation-related metabolic diseases.
Aphamines A–C (1–3), three pairs of acyclic diterpene dimer enantiomers with an unprecedent ploymerization pattern, were discovered from Aphanamixis polystachya by NMR-guided isolation and chiral resolution. The elucidation of their novel carbon skeletons was achieved based on spectroscopic analysis, exciton chirality, and calculated electronic circular dichroism (ECD). Plausible Claisen rearrangement, 5-exo-trig cyclization, and reduction reactions may play important roles in the polymeric biosynthesis pathway. Compounds 1 and 3 showed inhibitory effects on nitric oxide (NO) production (IC50: 6.71–15.36 μmol/L) and reduced the expression of iNOS in LPS-induced RAW 264.7 macrophages.
Metal organic frameworks (MOFs) derived carbonaceous materials have a wide range of applications in the fields of energy storage, catalysis, adsorption and separation, etc. Especially, zeolitic imidazolate framework-8 (ZIF-8) is an excellent candidate to synthesize porous carbon due to the large surface area and high nitrogen content. However, the dominated microporous structure of ZIF-8-derived carbon significantly hinders ionic mass transfer, limiting the improvement of performance. Herein, MOF-derived mesoporous carbon was prepared using ZIF-8 as carbon precursor and cheap sodium silicate (Na2SiO3) as activator. The introduction of Na2SiO3 created rich mesoporous structure and increased specific surface area, as well as the effects of pyrolysis temperature and Na2SiO3 dosage on performance was also investigated. The obtained ZIF-derived porous carbon exhibits good electrochemical performance with specific capacitance of 263 F/g at 1 A/g and excellent cycle life (96.07% after 10,000 GCD cycles) in supercapacitor. The use of cheap Na2SiO3 activator provides a new orientation for the preparation of MOF-derived carbons with rich pores, high surface area, and facilitates the large-scale application of MOF-derived carbons.
A new nonporous Zn-based metal-organic framework (NPMOF) synthesized from a high nitrogen-containing rigid ligand was converted into porous carbon materials by direct carbonization without adding additional carbon sources. A series of NPMOF-derived porous carbons with very high N/O contents (24.1% for NPMOF-700, 20.2% for NPMOF-800, 15.1% for NPMOF-900) were prepared by adjusting the pyrolysis temperatures. The NPMOF-800 fabricated electrode exhibits a high capacitance of 220 F/g and extremely large surface area normalized capacitance of 57.7 μF/cm2 compared to other reported MOF-derived porous carbon electrodes, which could be attributed to the abundant ultramicroporosity and high N/O co-doping. More importantly, symmetric supercapacitor assembled with the MOF-derived carbon manifests prominent stability, i.e., 99.1% capacitance retention after 10,000 cycles at 1.0 A/g. This simple preparation of MOF-derived porous carbon materials not only finds an application direction for a variety of porous or even nonporous MOFs, but also opens a way for the production of porous carbon materials for superior energy storage.
Surface-enhanced Raman scattering (SERS) is a powerful spectroscopic tool in quantitative analysis of molecules, where the substrate plays a critical role in determining the detection performance. Herein, a silver nanocubes/polyelectrolyte/gold film sandwich structure was prepared as a reproducible, high-performance SERS substrate by the water/oil interfacial assembly method. In addition to the hot spots on the nanocubes surface, the edge-to-edge interspace of the Ag nanocubes led to marked enhancement of the SERS intensity, with a limit of detection of 10-11 mol/L and limit of quantitation of 10-10 mol/L for crystal violet. When rhodamine 6G and crystal violet were co-adsorbed on the Ag nanocube surfaces, the characteristic SERS peaks of the two molecules remained well resolved and separated, and the peak intensities varied with the respective concentration, which could be exploited for concurrent detection of dual molecules. Results from this work indicate that organized ensembles of Ag nanocubes can serve as effective SERS substrate can for sensitive analysis for complex molecular systems.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
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
