Three-Dimensionally Nanometallic Superstructure Synthesized via a Single-Particle Soft-Enveloping Strategy.

Three-dimensionally (3D) integrated metallic nanomaterials composed of two or more different types of nanostructures make up a class of advanced materials due to the multidimensional and synergistic effects between different components. However, designing and synthesizing intricate, well-defined metallic 3D nanomaterials remain great challenges. Here, a novel single-particle soft-enveloping strategy using a core-shell Au NP@mSiO2 particle as a template was proposed to synthesize 3D nanomaterials, namely, a Au nanoparticle@center-radial nanorod-Au-Pt nanoparticle (Au NP@NR-NP-Pt NP) superstructure. Taking advantage of the excellent plasmonic properties of Au NP@NR-NP by the synergistic plasmonic coupling of the outer Au NPs and inner Au nanorods, we can enhance the catalytic performance for 4-nitrophenol hydrogenation using Au NP@NR-NP-Pt NP as a photocatalyst with plasmon-excited hot electrons from Au NP@NR-NP under light irradiation, which is 2.76 times higher than in the dark. This process opens a door for the design of a new generation of 3D metallic nanomaterials for different fields.

Wide-Temperature and High-Rate Operation of Lithium Metal Batteries Enabled by an Ionic Liquid Functionalized Quasi-Solid-State Electrolyte.

The development of high-energy-density solid-state lithium metal battery has been hindered by the unstable cycling of Ni-rich cathodes at high rate and limited wide-temperatures adoptability. In this study, an ionic liquid functionalized quasi-solid-state electrolyte (FQSE) is prepared to address these challenges. The FQSE features a semi-immobilized ionic liquid capable of anchoring solvent molecules through electrostatic interactions, which facilitates Li+ desolvation and reduces deleterious solvent-cathode reactions. The FQSE exhibits impressive electrochemical characteristics, including high ionic conductivity (1.9 mS cm-1 at 30 °C and 0.2 mS cm-1 at -30 °C) and a Li+ transfer number of 0.7. Consequently, Li/NCM811 cells incorporating FQSE demonstrate exceptional stability during high-rate cycling, enduring 700 cycles at 1 C. Notably, the Li/LFP cells with FQSE maintain high capacity across a wide temperature range, from -30 to 60 °C. This research provides a new way to promote the practical application of high-energy lithium metal batteries.

Lab-on-Device Synthesis of Hierarchical Macro/Mesoporous WO3 Semiconducting Films for High-Performance H2S Sensing.

The performance consistency of the gas sensor is strongly dependent on the interface binding between the sensitive materials and the electrodes. Traditional powder coating methods can inevitably lead to differences in terms of substrate-film interface interaction and device performance, affecting the stability and lifetime. Thus, efficient growth of sensitive materials on device substrates is crucial and essential to enhance the sensing performance, especially for stability. Herein, hierarchically ordered macro/mesoporous WO3 films are in situ synthesized on the electrode via a facile soft/hard dual-template strategy. Orderly arrayed uniform polystyrene (PS) microspheres with tailored size (ca. 1.2 µm) are used as a hard template, and surfactant Pluronic F127 as a soft template can co-assemble with tungsten precursor into ordered mesostructure in the interstitials of PS colloidal crystal induced by solvent evaporation. Benefiting from its rich porosity and high stability, the macro/mesoporous WO3-based sensor shows high sensitivity (Rair/Rgas = 307), fast response/recovery speed (5/9 s), and excellent selectivity (SH2S/Smax > 7) toward 50 ppm H2S gas (a biomarker for halitosis). Significantly, the sensors exhibit an extended service life with a negligible change in sensing performance within 60 days. This lab-on-device synthesis provides a platform method for constructing stable nanodevices with good consistency and high stability, which are highly desired for developing high-performance sensors.

Construction of Magnetic Core-Large Mesoporous Satellite Immunosensor for Long-Lasting Chemiluminescence and Highly Sensitive Tumor Marker Determination.

Chemiluminescence immunoassay exhibits high sensitivity and signal-to-noise ratio, thus attracting great attention in the early diagnosis and dynamic monitoring of diseases. However, the collection of conventional flash-type chemiluminescence signal (<5 s) relies heavily on automatic sampling and reading instrument. Herein, a novel core-satellite multifunctional chemiluminescence immunosensor is designed for the efficient enrichment and highly sensitive determination of cancer biomarker carcinoembryonic antigen (CEA) with enhanced and long-lasting output signal that can be conveniently recorded by a simple microplate plate reading instrument. Anti-CEA monoclonal antibody 2 (Ab2) modified Fe3 O4 @SiO2 microspheres (Fe3 O4 @SiO2 -Ab2, 370 nm in diameter) are synthesized as the core for selectively capturing and enriching target CEA in solution, and anti-human CEA monoclonal antibody 1 (Ab1) and horseradish peroxidase (HRP) co-immobilized dendritic large-mesoporous silica nanospheres (MSNs-HRP/Ab1, 80 nm in diameter, pore size: 17 nm) are synthesized as the satellite for efficient immunological recognition and signal amplification. The as-designed core-satellite magnetic chemiluminescence immunosensors exhibit a broad linear range of 0.01-20 ng mL-1 and a low detection limit of 3.0 pg mL-1 for the convenient, highly specific, and sensitive determination of CEA in human serum. Such core-satellite chemiluminescence immunosensors are expected to act as a powerful tool for in vitro detection of various biomarkers, overcome the defect of conventional chemiluminescence relying heavily on expensive and bulky automatic instruments and popularize chemiluminescence analysis to primary medical institutions and remote areas.

Micellar Nanoreactors Enabled Site-Selective Decoration of Pt Nanoparticles Functionalized Mesoporous SiO2 /WO3-x Composites for Improved CO Sensing.

Site-selective and partial decoration of supported metal nanoparticles (NPs) with transition metal oxides (e.g., FeOx ) can remarkably improve its catalytic performance and maintain the functions of the carrier. However, it is challenging to selectively deposit transition metal oxides on the metal NPs embedded in the mesopores of supporting matrix through conventional deposition method. Herein, a restricted in situ site-selective modification strategy utilizing poly(ethylene oxide)-block-polystyrene (PEO-b-PS) micellar nanoreactors is proposed to overcome such an obstacle. The PEO shell of PEO-b-PS micelles interacts with the hydrolyzed tungsten salts and silica precursors, while the hydrophobic organoplatinum complex and ferrocene are confined in the hydrophobic PS core. The thermal treatment leads to mesoporous SiO2 /WO3-x framework, and meanwhile FeOx nanolayers are in situ partially deposited on the supported Pt NPs due to the strong metal-support interaction between FeOx and Pt. The selective modification of Pt NPs with FeOx makes the Pt NPs present an electron-deficient state, which promotes the mobility of CO and activates the oxidation of CO. Therefore, mesoporous SiO2 /WO3-x -FeOx /Pt based gas sensors show a high sensitivity (31 ± 2 in 50 ppm of CO), excellent selectivity, and fast response time (3.6 s to 25 ppm) to CO gas at low operating temperature (66 °C, 74% relative humidity).

Pt-Pd Nanoalloys Functionalized Mesoporous SnO2 Spheres: Tailored Synthesis, Sensing Mechanism, and Device Integration.

Methane (CH4 ), as the vital energy resource and industrial chemicals, is highly flammable and explosive for concentrations above the explosive limit, triggering potential risks to personal and production safety. Therefore, exploiting smart gas sensors for real-time monitoring of CH4 becomes extremely important. Herein, the Pt-Pd nanoalloy functionalized mesoporous SnO2 microspheres (Pt-Pd/SnO2 ) were synthesized, which show uniform diameter (≈500 nm), high surface area (40.9-56.5 m2 g-1 ), and large mesopore size (8.8-15.8 nm). The highly dispersed Pt-Pd nanoalloys are confined in the mesopores of SnO2 , causing the generation ofoxygen defects and increasing the carrier concentration of sensitive materials. The representative Pt1 -Pd4 /SnO2 exhibits superior CH4 sensing performance with ultrahigh response (Ra /Rg = 21.33 to 3000 ppm), fast response/recovery speed (4/9 s), as well as outstanding stability. Spectroscopic analyses imply that such an excellent CH4 sensing process involves the fast conversion of CH4 into formic acid and CO intermediates, and finally into CO2 . Density functional theory (DFT) calculations reveal that the attractive covalent bonding interaction and rapid electron transfer between the Pt-Pd nanoalloys and SnO2 support, dramatically promote the orbital hybridization of Pd4 sites and adsorbed CH4 molecules, enhancing the catalytic activation of CH4 over the sensing layer.

Interfacial Assembly and Applications of Functional Mesoporous Materials.

Functional mesoporous materials have gained tremendous attention due to their distinctive properties and potential applications. In recent decades, the self-assembly of micelles and framework precursors into mesostructures on the liquid-solid, liquid-liquid, and gas-liquid interface has been explored in the construction of functional mesoporous materials with diverse compositions, morphologies, mesostructures, and pore sizes. Compared with the one-phase solution synthetic approach, the introduction of a two-phase interface in the synthetic system changes self-assembly behaviors between micelles and framework species, leading to the possibility for the on-demand fabrication of unique mesoporous architectures. In addition, controlling the interfacial tension is critical to manipulate the self-assembly process for precise synthesis. In particular, recent breakthroughs based on the concept of the "monomicelles" assembly mechanism are very promising and interesting for the synthesis of functional mesoporous materials with the precise control. In this review, we highlight the synthetic strategies, principles, and interface engineering at the macroscale, microscale, and nanoscale for oriented interfacial assembly of functional mesoporous materials over the past 10 years. The potential applications in various fields, including adsorption, separation, sensors, catalysis, energy storage, solar cells, and biomedicine, are discussed. Finally, we also propose the remaining challenges, possible directions, and opportunities in this field for the future outlook.

Cocrystallization Enabled Spatial Self-Confinement Approach to Synthesize Crystalline Porous Metal Oxide Nanosheets for Gas Sensing.

Crystalline metal oxide nanosheets show exceptional catalytic performance owing to the large surface-to-volume ratio and quantum confinement effect. However, it is still a challenge to develop a facile and general method to synthesize metal oxide nanosheets. Herein, we report a cocrystallization induced spatial self-confinement approach to synthesize metal oxide nanosheets. Taking the synthesis of SnO2 as an example, the solvent evaporation from KCl and SnCl2 solution induces the cocrystallization of KCl and K2 SnCl6 , and the obtained composite with encapsulated K2 SnCl6 can be in situ converted into SnO2 nanosheets confined in KCl matrix, after water washing to remove KCl, porous SnO2 nanosheets can be obtained. Notably, a series of metal oxide nanosheets can be obtained through this general and efficient green route. In particular, porous CeO2 /SnO2 nanosheets with improved surface O- species and abundant oxygen vacancies exhibit superior gas sensing performance to 3-hydroxy-2-butanone.

Mesoporous Materials-Based Electrochemical Biosensors from Enzymatic to Nonenzymatic.

Mesoporous materials have drawn more and more attention in the field of biosensors due to their high surface areas, large pore volumes, tunable pore sizes, as well as abundant frameworks. In this review, the progress on mesoporous materials-based biosensors from enzymatic to nonenzymatic are highlighted. First, recent advances on the application of mesoporous materials as supports to stabilize enzymes in enzymatic biosensing technology are summarized. Special emphasis is placed on the effect of pore size, pore structure, and surface functional groups of the support on the immobilization efficiency of enzymes and the biosensing performance. Then, the development of a nonenzymatic strategy that uses the intrinsic property of mesoporous materials (carbon, silica, metals, and composites) to mimic the behavior of enzymes for electrochemical sensing of some biomolecules is discussed. Finally, the challenges and perspective on the future development of biosensors based on mesoporous materials are proposed.

Self-Hybrid Transition Metal Oxide Nanosheets Synthesized by a Facile Programmable and Scalable Carbonate-Template Method.

2D transition metal oxides (TMO) nanosheets have attracted considerable attention in both fundamental research and practical applications. Herein, a convenient programmable and scalable carbonate crystals templating synthesis is developed to produce high-quality self-hybrid TMO nanosheets (Si-WO3- x , Tax Oy , Mnx Oy ) and their respective polymetallic oxide hybrid nanosheets with tunable composition, low-cost and high-yield. Taking tungsten oxide nanosheets as example, silicotungstic acid precursor is in situ converted into tungsten oxide nanosheets like scales on the surface of calcium carbonate crystals through the simple soaking-drying-calcination process, and after selectively dissolving calcium carbonate by etching, the dispersive tungsten oxide nanosheets with unique self-hybrid Si-doped h-WO3 /ε-WO3 /WO2 compositions are obtained, which show excellent acetone gas-sensing performances at low temperatures. This carbonate-template method opens up the possibility to economically produce various functional TMO nanosheets with specific compositions for diverse applications.

Structure Engineering of Yolk-Shell Magnetic Mesoporous Silica Microspheres with Broccoli-Like Morphology for Efficient Catalysis and Enhanced Cellular Uptake.

Yolk-shell magnetic mesoporous microspheres exhibit potential applications in biomedicine, bioseparation, and catalysis. Most previous reports focus on establishing various interface assembly strategies to construct yolk-shell mesoporous structures, while little work has been done to control their surface topology and study their relevant applications. Herein, a unique kind of broccoli-like yolk-shell magnetic mesoporous silica (YS-BMM) microsphere is fabricated through a surfactant-free kinetic controlled interface assembly strategy. The obtained YS-BMM microspheres possess a well-defined structure consisting of a magnetic core, middle void, mesoporous silica shell with tunable surface roughness, large superparamagnetism (36.4 emu g-1 ), high specific surface area (174 m2 g-1 ), and large mesopores of 10.9 nm. Thanks to these merits and properties, the YS-BMM microspheres are demonstrated to be an ideal support for immobilization of ultrafine Pt nanoparticles (≈3.7 nm) and serve as superior nanocatalysts for hydrogenation of 4-nitrophenol with yield of over 90% and good magnetic recyclability. Furthermore, YS-BMM microspheres show excellent biocompatibility and can be easily phagocytosed by osteoclasts, revealing a potential candidate in sustained drug release in orthopedic disease therapy.

Synthesis of orthogonally assembled 3D cross-stacked metal oxide semiconducting nanowires.

Assemblies of metal oxide nanowires in 3D stacks can enable the realization of nanodevices with tailored conductivity, porous structure and a high surface area. Current fabrication methods require complicated multistep procedures that involve the initial preparation of nanowires followed by manual assembly or transfer printing, and thus lack synthesis flexibility and controllability. Here we report a general synthetic orthogonal assembly approach to controllably construct 3D multilayer-crossed metal oxide nanowire arrays. Taking tungsten oxide semiconducting nanowires as an example, we show the spontaneous orthogonal packing of composite nanorods of poly(ethylene oxide)-block-polystyrene and silicotungstic acid; the following calcination gives rise to 3D cross-stacked nanowire arrays of Si-doped metastable ε-phase WO3. This nanowire stack framework was also tested as a gas detector for the selective sensing of acetone. By using other polyoxometallates, this fabrication method for woodpile-like 3D nanostructures can also be generalized to different doped metal oxide nanowires, which provides a way to manipulate their physical properties for various applications.

Prolonged use of nitric oxide donor sodium nitroprusside induces ocular hypertension in mice.

Nitric oxide (NO) donors are promising therapeutic candidates for treating intraocular hypertension (IOP) and glaucoma. This study aims to investigate the effect of prolonged use of NO donor sodium nitroprusside (SNP) on IOP. Since SNP has a short biological half-life, a nanoparticle drug delivery system (mesoporous silica nanoparticles) has been used to deliver SNP to the target tissues (trabecular meshwork and Schlemm's canal). We find that the sustained use of NO donor initially reduced IOP followed, surprisingly, by IOP elevation, which could not recover by drug withdraw but could be reversed by the antioxidant MnTMPyP application. The IOP elevation and normalization coincide with increased and reduced protein nitration in the mouse conventional outflow tissue. These findings suggest that the prolonged use of NO donor SNP may be problematic as it can cause outflow tissue damage by protein nitration. MnTMPyP is protective of the nitrative damage which could be considered to be co-applied with NO donors.

Recent advances in amphiphilic block copolymer templated mesoporous metal-based materials: assembly engineering and applications.

Mesoporous metal-based materials (MMBMs) have received unprecedented attention in catalysis, sensing, and energy storage and conversion owing to their unique electronic structures, uniform mesopore size and high specific surface area. In the last decade, great progress has been made in the design and application of MMBMs; in particular, many novel assembly engineering methods and strategies based on amphiphilic block copolymers as structure-directing agents have also been developed for the "bottom-up" construction of a variety of MMBMs. Development of MMBMs is therefore of significant importance from both academic and practical points of view. In this review, we provide a systematic elaboration of the molecular assembly methods and strategies for MMBMs, such as tuning the driving force between amphiphilic block copolymers and various precursors (i.e., metal salts, nanoparticles/clusters and polyoxometalates) for pore characteristics and physicochemical properties. The structure-performance relationship of MMBMs (e.g., pore size, surface area, crystallinity and crystal structure) based on various spectroscopy analysis techniques and density functional theory (DFT) calculation is discussed and the influence of the surface/interfacial properties of MMBMs (e.g., active surfaces, heterojunctions, binding sites and acid-base properties) in various applications is also included. The prospect of accurately designing functional mesoporous materials and future research directions in the field of MMBMs is pointed out in this review, and it will open a new avenue for the inorganic-organic assembly in various fields.

Au Nanoparticles Decorated Mesoporous SiO2 -WO3 Hybrid Materials with Improved Pore Connectivity for Ultratrace Ethanol Detection at Low Operating Temperature.

Semiconducting metal oxides-based gas sensors with the capability to detect trace gases at low operating temperatures are highly desired in applications such as wearable devices, trace pollutant detection, and exhaled breath analysis, but it still remains a great challenge to realize this goal. Herein, a multi-component co-assembly method in combination with pore engineering strategy is proposed. By using bi-functional (3-mercaptopropyl) trimethoxysilane (MPTMS) that can co-hydrolyze with transition metal salt and meanwhile coordinate with gold precursor during their co-assembly with PEO-b-PS copolymers, ordered mesoporous SiO2 -WO3 composites with highly dispersed Au nanoparticles of 5 nm (mesoporous SiO2 -WO3 /Au) are straightforward synthesized. This multi-component co-assembly process avoids the aggregation of Au nanoparticles and pore blocking in conventional post-loading method. Furthermore, through controlled etching treatment, a small portion of silica can be removed from the pore wall, resulting in mesoporous SiO2 -WO3 /Au with increased specific surface area (129 m2  g-1 ), significantly improved pore connectivity, and enlarged pore window (>4.3 nm). Thanks to the presence of well-confined Au nanoparticles and ε-WO3 , the mesoporous SiO2 -WO3 /Au based gas sensors exhibit excellent sensing performance toward ethanol with high sensitivity (Ra /Rg = 2-14 to 50-250 ppb) at low operating temperature (150 °C).

sp2-Hybridized Carbon-Containing Block Copolymer Templated Synthesis of Mesoporous Semiconducting Metal Oxides with Excellent Gas Sensing Property.

In recent years, rational design of ordered mesoporous metal oxides, especially metal oxide semiconductors with adjustable pore architecture and framework compositions, has aroused extensive research interest owing to their unique electronic structures, long-range ordered porous framework, uniform mesopore size, and high specific surface area. Research on mesoporous materials has been booming in the past 30 years, and many synthesis methods have been developed, such as templating methods based on amphiphilic copolymers as soft templates or mesoporous carbon/silica as hard templates, respectively. Soft-templating synthesis has been considered as one of the most efficient and flexible methods in designing ordered mesoporous materials through the controllable interfacial induced coassembly process. However, most commercial amphiphilic copolymers, such as poly(ethylene oxide)- b-poly(propylene oxide) based Pluronic-type ones, suffer the drawback of poor thermal stability, because they are too easy to be decomposed even in inert atmosphere. Therefore, they are difficult to support the structures of mesoporous metal oxides under high calcination temperatures (>400 °C). To solve this challenge, we designed new amphiphilic block copolymers with high content of sp2-hybridized carbon in the hydrophobic segments that were relatively stable and could be in situ converted into residual carbon to support the mesoporous structure, via living free radical polymerization. We developed a variety of novel synthesis methods based on sp2-hybridized carbon-containing block copolymer, such as ligand-assisted assembly and resol-assisted assembly strategies, achieving a controllable and versatile synthesis of mesoporous semiconducting metal oxides with excellent gas sensing performance. In this Account, we first outline the features of sp2-hybridized carbon-containing block copolymers synthesized via living free radical polymerization, particularly their pyrolysis behavior in converting into residual carbon. Combining the solvent evaporation induced coassembly and the carbon-supported crystallization strategies, we realized the rational design of various ordered mesoporous semiconducting metal oxides (e.g., WO3, SnO2, Co3O4, In2O3, TiO2, ZnO) and the regulation of their architectural features. To overcome the fast hydrolysis rate of metal precursors and weak interaction between block copolymers and metal precursors, we developed efficient ligand-assisted (e.g., acetylacetone and acetic acid) coassembly and resol-assisted coassembly methods to retard hydrolysis behavior and enhance the interaction via hydrogen bonds, covalent bonds, electrostatic interactions, etc. We also highlight the applications of these ordered mesoporous semiconducting metal oxides of both n-type and p-type in gas sensing fields, and they show tremendous sensing performance due to their abundant active sites on electron depletion layer and rapid gas diffusion via accessible pore channels. Finally, on the basis of the classic surface-electron depletion layer model, we elucidated in depth the surface catalytic reactions between the target gas molecules and the activated species (e.g., the adsorbed oxygen species) in the surface of mesoporous metal oxides during sensing process. These newly developed soft-templating synthesis methods that rely on sp2-hybridized carbon-containing block copolymers will open a new avenue for the design and application of ordered mesoporous semiconducting metal oxides in various fields.

Advances in the Interfacial Assembly of Mesoporous Silica on Magnetite Particles.

Interfacing magnetic particles with ordered mesoporous materials is an effective direction for the development of functional porous composite materials with rationally designed core-shell structures. Owing to the combined properties of magnetic nanoparticles and mesoporous silica (high surface area, large pore volume, porosity, and biocompatibility), core-shell magnetic mesoporous silica materials have generated tremendous interest in various disciplines, including chemistry, materials, bioengineering, and biomedicine. Interfacial assembly strategies enable the rational construction of magnetic mesoporous silica materials with well-defined core-shell structure, morphology, pore parameters, and surface wettability, which can decisively influence their physical and chemical properties and thus improve their application performance. This Minireview summarizes recent progress in the synthesis of core-shell magnetic mesoporous silica and the adjustment of key parameters, including pore size, morphology, and pore orientation.

Large-Pore Mesoporous CeO2 -ZrO2 Solid Solutions with In-Pore Confined Pt Nanoparticles for Enhanced CO Oxidation.

Active and stable catalysts are highly desired for converting harmful substances (e.g., CO, NOx ) in exhaust gases of vehicles into safe gases at low exhaust temperatures. Here, a solvent evaporation-induced co-assembly process is employed to design ordered mesoporous Cex Zr1- x O2 (0 ≤ x ≤ 1) solid solutions by using high-molecular-weight poly(ethylene oxide)-block-polystyrene as the template. The obtained mesoporous Cex Zr1- x O2 possesses high surface area (60-100 m2 g-1 ) and large pore size (12-15 nm), enabling its great capacity in stably immobilizing Pt nanoparticles (4.0 nm) without blocking pore channels. The obtained mesoporous Pt/Ce0.8 Zr0.2 O2 catalyst exhibits superior CO oxidation activity with a very low T100 value of 130 °C (temperature of 100% CO conversion) and excellent stability due to the rich lattice oxygen vacancies in the Ce0.8 Zr0.2 O2 framework. The simulated catalytic evaluations of CO oxidation combined with various characterizations reveal that the intrinsic high surface oxygen mobility and well-interconnected pore structure of the mesoporous Pt/Ce0.8 Zr0.2 O2 catalyst are responsible for the remarkable catalytic efficiency. Additionally, compared with mesoporous Pt/Cex Zr1- x O2 -s with small pore size (3.8 nm), ordered mesoporous Pt/Cex Zr1- x O2 not only facilitates the mass diffusion of reactants and products, but also provides abundant anchoring sites for Pt nanoparticles and numerous exposed catalytically active interfaces for efficient heterogeneous catalysis.

Nonsacrificial Self-Template Synthesis of Colloidal Magnetic Yolk-Shell Mesoporous Organosilicas for Efficient Oil/Water Interface Catalysis.

Using interfacial reaction systems for biphasic catalytic reactions is attracting more and more attention due to their simple reaction process and low environmental pollution. Yolk-shell structured materials have broad applications in biomedicine, catalysis, and environmental remediation owing to their open channels and large space for guest molecules. Conventional methods to obtain yolk-shell mesoporous materials rely on costly and complex hard-template strategies. In this study, a mild and convenient nonsacrificial self-template strategy is developed to construct yolk-shell magnetic periodic mesoporous organosilica (YS-mPMO) particles by using the unique swelling-deswelling property of low-crosslinking density resorcinol formaldehyde (RF). The obtained YS-mPMO microspheres possess an amphiphilic outer shell, high surface area (393 m2 g-1 ), uniform mesopores (2.58 nm), a tunable middle hollow space (50-156 nm), and high superparamagnetism (34.4-37.1 emu g-1 ). By tuning the synthesis conditions, heterojunction structured yolk-shell Fe3 O4 @RF@void@PMO particles with different morphologies can be produced. Owing to the amphipathy of PMO framworks, the YS-mPMO particles show great emulsion stabilization ability and recyclability under a magnetic field. YS-mPMO microspheres with immobilized Au nanoparticles (≈3 nm) act as both solid emulsifier for dispersing styrene (St) in water and interface catalysts for selective conversion of St into styrene oxide with a high selectivity of 86%, and yields of over 97%.

A General and Straightforward Route to Noble Metal-Decorated Mesoporous Transition-Metal Oxides with Enhanced Gas Sensing Performance.

Controllable and efficient synthesis of noble metal/transition-metal oxide (TMO) composites with tailored nanostructures and precise components is essential for their application. Herein, a general mercaptosilane-assisted one-pot coassembly approach is developed to synthesize ordered mesoporous TMOs with agglomerated-free noble metal nanoparticles, including Au/WO3 , Au/TiO2 , Au/NbOx , and Pt/WO3 . 3-mercaptopropyl trimethoxysilane is applied as a bridge agent to cohydrolyze with metal oxide precursors by alkoxysilane moieties and interact with the noble metal source (e.g., HAuCl4 and H2 PtCl4 ) by mercapto (SH) groups, resulting in coassembly with poly(ethylene oxide)-b-polystyrene. The noble metal decorated TMO materials exhibit highly ordered mesoporous structure, large pore size (≈14-20 nm), high specific surface area (61-138 m2 g-1 ), and highly dispersed noble metal (e.g., Au and Pt) nanoparticles. In the system of Au/WO3 , in situ generated SiO2 incorporation not only enhances their thermal stability but also induces the formation of ε-phase WO3 promoting gas sensing performance. Owning to its specific compositions and structure, the gas sensor based on Au/WO3 materials possess enhanced ethanol sensing performance with a good response (Rair /Rgas = 36-50 ppm of ethanol), high selectivity, and excellent low-concentration detection capability (down to 50 ppb) at low working temperature (200 °C).