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With the rapid development of nanotechnology and catalysis science, numerous enzyme-mimicking nanomaterials have been rationally designed as the substitutes for natural enzymes. Herein, the Pt-loaded hollow mesoporous carbon nanospheres (Pt-HMCNs) were proposed as the peroxidase mimic for the first time. The monodispersed HMCNs with huge hollow cavity and mesoporous carbon skeleton were first synthesized via high-temperature carbonization and NaOH etching of core–shell structured SiO2@RF/SiO2 (RF = resorcinol–formaldehyde resin) nanospheres, which were prepared through a simple surfactant-free strategy in a one-pot system only containing three main raw chemicals as tetraethyl orthosilicate, resorcinol, and formaldehyde. And then the Pt-HMCNs were obtained through surface graft of −NH2 groups and loading of as-synthesized ultrasmall Pt nanoparticles (NPs) in size of 1–3 nm on the HMCNs. The prepared Pt-HMCNs nanocomposites exhibited superior peroxidase-like catalytic activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) substrate, which owned stronger affinity to H2O2 and TMB as substrates than the natural enzyme (horseradish peroxidase). The outstanding peroxidase-mimic performance of the Pt-HMCNs is due to the unique hollow mesoporous structure as well as the interfacial effect between Pt NPs and carbon skeleton. A simple and general colorimetric approach was established to accurately detect ascorbic acid (AA) and glucose, and their detection limits were calculated to be 3.29 and 35.4 μM, respectively. Besides, wide linear range and high selectivity against interfering substances were also achieved in this assay during AA and glucose detection based on the Pt-HMCNs catalyst. The colorimetric method built on Pt-HMCNs in this work could be applied to biomedicine, food science, environment monitoring, and other fields for accurately detecting ascorbic acid, glucose, and other important substances in some complex systems. [ABSTRACT FROM AUTHOR]

Owing to their distinct chemical and physical properties, mesoporous metal oxide semiconductors have shown great application potential in catalysis, electrochemistry, energy conversion, and energy storage. In this study, mesoporous crystalline SnO 2 materials have been synthesized through an evaporation-induced co-assembly (EICA) method using poly(ethylene oxide)-b-polystyrene diblock copolymers as the template, tin chlorides as the tin sources, and tetrahydrofuran as the solvent. By controlling conditions of the co-assembly process and employing a carbon-supported thermal treatment strategy, highly ordered mesoporous SnO 2 materials with a hexagonal mesostructure (space group P6 3 /mmc) and crystalline pore walls can be obtained. The mesoporous SnO 2 is employed for fabricating gas sensor nanodevices which exhibit an excellent sensing performance toward H 2 S with high sensitivity (170, 50 ppm) and superior stability, owing to its high surface area (98 m 2 /g), well-connected mesopores of ca. 18.0 nm, and high density of active sites in the crystalline pore walls. The chemical mechanism study reveals that both SO 2 and SnS 2 are generated during the gas sensing process on the SnO 2 -based sensors.

Yolk-shell nanomaterials with a rattle-like structure have been considered ideal carriers and nanoreactors. Traditional methods to constructing yolk-shell nanostructures mainly rely on multistep sacrificial template strategy. In this study, a facile and effective plasmolysis-inspired nanoengineering strategy is developed to controllably fabricate yolk-shell magnetic mesoporous silica microspheres via the swelling-shrinkage of resorcinol-formaldehyde (RF) upon soaking in or removal of n-hexane. Using Fe 3 O 4 @RF microspheres as seeds, surfactant-silica mesostructured composite is deposited on the swelled seeds through the multicomponent interface coassembly, followed by solvent extraction to remove surfactant and simultaneously induce shrinkage of RF shell. The obtained yolk-shell microspheres (Fe 3 O 4 @RF@void@mSiO 2 ) possess a high magnetization of 40.3 emu/g, high surface area (439 m 2 /g), radially aligned mesopores (5.4 nm) in the outer shell, tunable middle hollow space (472-638 nm in diameter), and a superparamagnetic core. This simple method allows a simultaneous encapsulation of Au nanoparticles into the hollow space during synthesis, and it leads to spherical Fe 3 O 4 @RF@void-Au@mSiO 2 magnetic nanocatalysts, which show excellent catalysis efficiency for hydrogenation of 4-nitrophenol by NaBH 4 with a high conversion rate (98%) and magnetic recycling stability.

Foodborne pathogens like Listeria monocytogenes can cause various illnesses and pose a serious threat to public health. They produce species-specific microbial volatile organic compounds, i.e., the biomarkers, making it possible to indirectly measure microbial contamination in foodstuff. Herein, highly ordered mesoporous tungsten oxides with high surface areas and tunable pores have been synthesized and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace Listeria monocytogenes. The mesoporous WO 3 -based chemiresistive sensors exhibit a rapid response, superior sensitivity, and highly selective detection of 3-hydroxy-2-butanone. The chemical mechanism study reveals that acetic acid is the main product generated by the surface catalytic reaction of the biomarker molecule over mesoporous WO 3 . Furthermore, by using the mesoporous WO 3 -based sensors, a rapid bacteria detection was achieved, with a high sensitivity, a linear relationship in a broad range, and a high specificity for Listeria monocytogenes. Such a good gas sensing performance foresees the great potential application of mesoporous WO 3 -based sensors for fast and effective detection of microbial contamination for the safety of food, water safety and public health.

Functional core-shell mesoporous microspheres with integrated functions, controlled structure, and surface properties and morphologies have received increasing attention due to their excellent physicochemical properties. Herein, core-shell magnetic mesoporous materials with cauliflower-like morphology and tunable surface roughness have been synthesized through a kinetics-controlled interface co-assembly and deposition of mesostructured nanocomposites on Fe 3 O 4 @RF microspheres (RF refers to resorcinol formaldehyde resin). The obtained microspheres, synthesized via this interface nanoengineering method, possess well-defined sandwich structure with a tunable rough morphology, uniform size (560-1000 nm), perpendicularly aligned mesopores (∼5.7 nm) in the outer shell, RF-protected magnetic responsive core, high surface area up to 382 m 2 /g, and large pore volume of 0.66 cm 3 /g. As a result of the unique surface features and magnetic properties, these microspheres exhibit excellent performance in stabilizing and oxygen-free manipulating aqueous solutions in petroleum ether by a magnetic field. They also exhibit superior cell uptake properties compared with traditional smooth core-shell magnetic mesoporous silica microspheres, opening up the possible applications in fast drug delivery in cancer therapy.

Nanostructured carbon materials have received considerable attention due to their special physicochemical properties. Herein, ordered mesoporous carbons (OMCs) with two-dimension (2D) hexagonal mesostructure and unique buckled large mesopores have successfully been synthesized via a micelle fusion-aggregation assembly method by using poly(ethylene oxide)-block-polystyrene (PEO-b-PS) diblock copolymers as a template and resorcinol-based phenolic resin as a carbon precursor. The obtained ordered mesoporous carbons possess unique fiber-like morphology, specific surface area of 571-880 m(2)/g, pore volume of 0.54 cm(3)/g and large mesopores (up to 36.3 nm) and high density of active sites (i.e., carboxylic groups) of 0.188/nm(2). Gas sensor based on the ordered mesoporous carbons exhibits an excellent performance in sensing NH3 at a low temperature with fast response (<2 min), ultralow limit of detection (<1 ppm), and good selectivity, due to the large pore sizes, high surface area and rich active sites in the carbon pore walls.

Core-shell magnetic mesoporous silica microspheres (Magn-MSMs) with tunable large mesopores in the shell are highly desired in biocatalysis, magnetic bioseparation, and enrichment. In this study, a shearing assisted interface coassembly in n-hexane/water biliquid systems is developed to synthesize uniform Magn-MSMs with magnetic core and mesoporous silica shell for an efficient size-selective biocatalysis. The synthesis features the rational control over the electrostatic interaction among cationic surfactant molecules, silicate oligomers, and Fe3O4@RF microspheres (RF: resorcinol formaldehyde) in the presence of shearing-regulated solubilization of n-hexane in surfactant micelles. Through this multicomponent interface coassembly, surfactant-silica mesostructured composite has been uniformly deposited on the Fe3O4@RF microspheres, and core-shell Magn-MSMs are obtained after removing the surfactant and n-hexane. The obtained Magn-MSMs possess excellent water dispersibility, uniform diameter (600 nm), large and tunable perpendicular mesopores (5.0-9.0 nm), high surface area (498-623 m(2)/g), large pore volume (0.91-0.98 cm(3)/g), and high magnetization (34.5-37.1 emu/g). By utilization of their large and open mesopores, Magn-MSMs with a pore size of about 9.0 nm have been demonstrated to be able to immobilize a large bioenzyme (trypsin with size of 4.0 nm) with a high loading capacity of ∼97 μg/mg via chemically binding. Magn-MSMs with immobilized trypsin exhibit an excellent convenient and size selective enzymolysis of low molecular proteins in the mixture of proteins of different sizes and a good recycling performance by using the magnetic separability of the microspheres.

A simple and efficient solution mixing method has been developed for the synthesis of the G-V2O5 nanocomposite. By this method, one-dimensional V2O5 rods are decorated onto the two-dimensional graphene sheets. The synthesized nanocomposites are characterized by XRD, SEM with elemental mapping, TEM, FT-IR, Raman, BET, and XPS analyses. The photocatalytic activity of the G-V2O5 nanocomposite studied with methylene blue dye shows strong degradation efficiency with direct sunlight irradiation compared to UV and visible light sources. The mechanism of methylene blue dye degradation by the G-V2O5 nanocomposite has been elucidated through the kinetics of the degradation process by calculating the rate constant and half-life time of the degradation process.