The rational design and controllable synthesis of hollow nanoparticles with both a mesoporous shell and an asymmetric architecture are crucially desired yet still significant challenges. In this work, a kinetics-controlled interfacial super-assembly strategy is developed, which is capable of preparing asymmetric porous and hollow carbon (APHC) nanoparticles through the precise regulation of polymerization and assembly rates of two kinds of precursors. In this method, Janus resin and silica hybrid (RSH) nanoparticles are first fabricated through the kinetics-controlled competitive nucleation and assembly of two precursors. Specifically, silica nanoparticles are initially formed, and the resin nanoparticles are subsequently formed on one side of the silica nanoparticles, followed by the co-assembly of silica and resin on the other side of the silica nanoparticles. The APHC nanoparticles are finally obtained via high-temperature carbonization of RSH nanoparticles and elimination of silica. The erratic asymmetrical, hierarchical porous and hollow structure and excellent photothermal performance under 980 nm near-infrared (NIR) light endow the APHC nanoparticles with the ability to serve as fuel-free nanomotors with NIR-light-driven propulsion. Upon illumination by NIR light, the photothermal effect of the APHC shell causes both self-thermophoresis and jet driving forces, which propel the APHC nanomotor. Furthermore, with the assistance of phase change materials, such APHC nanoparticles can be employed as smart vehicles that can achieve on-demand release of drugs with a 980 nm NIR laser. As a proof of concept, we apply this APHC-based therapeutic system in cancer treatment, which shows improved anticancer performance due to the synergy of photothermal therapy and chemotherapy. In brief, this kinetics-controlled approach may put forward new insight into the design and synthesis of functional materials with unique structures, properties, and applications by adjusting the assembly rates of multiple precursors in a reaction system.
In this communication, a concentrated solar light (CSL) annealing strategy is proposed with a Fresnel lens as the concentrator for rapid and effective crystallization of nanomaterials. More interestingly, the CSL can be integrated into photoelectrochemical devices and achieved an unprecedented photocurrent density.
Abstract Salinity gradient energy existing in seawater and river water is a sustainable and environmentally energy resource that has drawn significant attention of researchers in the background of energy crisis. Nanochannel membrane with a unique nano‐confinement effect has been widely applied to harvest the salinity gradient energy. Here, Janus porous heterochannels constructed from 2D graphene oxide modified with polyamide (PA‐GO) and oxide array (anodic aluminum oxide, AAO) are prepared through an interfacial super‐assembly method, which can achieve oriented ion transportation. Compared with traditional nanochannels, the PA‐GO/AAO heterochannels with asymmetric charge distribution and T‐mode geometrical nanochannel structure shows directional ionic rectification features and outstanding cation selectivity. The resulting heterochannel membrane can achieve a high‐power density of up to 3.73 W m −2 between artificial seawater and river water. Furthermore, high energy conversion efficiency of 30.3% even in high salinity gradient can be obtained. These achievable results indicate that the PA‐GO/AAO heterochannels has significant potential application in salinity gradient energy harvesting.
Micro/nanoscale robotics has received great attention in many important fields. However, it is still a great challenge to construct nanorobots simultaneously possessing multifunctionality, well-controlled directionality, and fast and durable motion as well as fully compatible and biodegradable components. Here, a hierarchical, asymmetric, hollow, catalytic, magnetic, and mesoporous nanorobot has been fabricated through a multistep interfacial superassembly strategy. The multilayer composites consist of hollow silica nanoflasks sequentially coated with a highly magnetic responsive Fe3 O4 layer, a mesoporous silica layer with homogeneous vertical channels, and a layer of catalytic gold nanoparticles on both the inner and outer surfaces. Furthermore, para-nitrophenol was used as a model pollutant to trigger self-motility of the nanoflasks by confined catalytic degradation (CCD). We found that the bottleneck morphology and mesoporous surface both improved the catalytic nanoparticle loading capability and CCD effect, thus enabling efficient self-motility and a durable movement capacity of ∼100 h. In addition, the catalytic performance was improved by 180 % compared with that of solid spherical nanoparticles.
The capture of sustainable energy from a salinity gradient, in particular, using renewable biomass-derived functional materials, has attracted significant attention. In order to convert osmotic energy to electricity, many membrane materials with nanofluidic channels have been developed. However, the high cost, complex preparation process, and low output power density still restrict the practical application of traditional membranes. Herein, we report the synthesis of highly flexible and mechanically robust nanofiber-arrays-based carbonaceous ordered mesoporous nanowires (CMWs) through a simple and straightforward soft-templating hydrothermal carbonization approach. This sequential superassembly strategy shows a high yield and great versatility in controlling the dimensions of CMWs with the aspect ratio changes from about 3 to 39. Furthermore, these CMWs can be used as novel building blocks to construct functional hybrid membranes on macroporous alumina. This nanofluidic membrane with asymmetric geometry and charge polarity exhibits low resistance and high-performance energy conversion. This work opens a solution-based route for the one-pot preparation of CMWs and functional heterostructure membranes for various applications.
In the field of sustainable chemistry, it is still a significant challenge to realize efficient light-powered space-confined catalysis and propulsion due to the limited solar absorption efficiency and the low mass and heat transfer efficiency. Here, novel semiconductor TiO2 nanorockets with asymmetric, hollow, mesoporous, and double-layer structures are successfully constructed through a facile interfacial superassembly strategy. The high concentration of defects and unique topological features improve light scattering and reduce the distance for charge migration and directed charge separation, resulting in enhanced light harvesting in the confined nanospace and resulting in enhanced catalysis and self-propulsion. The movement velocity of double-layered nanorockets can reach up to 10.5 μm s–1 under visible light, which is approximately 57 and 119% higher than that of asymmetric single-layered TiO2 and isotropic hollow TiO2 nanospheres, respectively. In addition, the double-layered nanorockets improve the degradation rate of the common pollutant methylene blue under sustainable visible light with a 247% rise of first-order rate constant compared to isotropic hollow TiO2 nanospheres. Furthermore, FEA simulations reveal and confirm the double-layered confined-space enhanced catalysis and self-propulsion mechanism.
Atomically dispersed catalysts are a new type of material in the field of catalysis science, yet their large-scale synthesis under mild conditions remains challenging. Here, a general synergistic capture-bonding superassembly strategy to obtain atomically dispersed Pt (Ru, Au, Pd, Ir, and Rh)-based catalysts on micropore-vacancy frameworks at a mild temperature of 60 °C is reported. The precise capture via narrow pores and the stable bonding of vacancies not only simplify the synthesis process of atomically dispersed catalysts but also realize their large-scale preparation at mild temperature. The prepared atomically dispersed Pt-based catalyst possesses a promising electrocatalytic activity for hydrogen evolution, showing an activity (at overpotential of 50 mV) about 21.4 and 20.8 times higher than that of commercial Pt/C catalyst in 1.0 M KOH and 0.5 M H2SO4, respectively. Besides, the extremely long operational stability of more than 100 h provides more potential for its practical application.
Abstract Asymmetric hollow and magnetic mesoporous silica nanocomposites have great potential applications due to their unique structural–functional properties. Here, asymmetric multilayer‐sandwich magnetic mesoporous silica nanobottles (MMSNBs) are presented through an interfacial super‐assembly strategy. Asymmetric hollow silica nanobottles (SNBs) are first prepared, and Fe 3 O 4 nanoparticles monolayers and mesoporous silica layers are uniformly super‐assembled on the surfaces of SNBs, respectively. The high Fe 3 O 4 nanoparticles loading endows MMSNBs with a high magnetization (8.5 emu g −1 ), while the mesoporous silica layers exhibit high surface area (613.4 m 2 g −1 ) and large pore size (3.6 nm). MMSNBs can be employed as a novel type of enzyme‐powered nanomotors by integrating catalase (Cat‐MMSNBs), which show an average speed of 7.59 µm s −1 (≈25 body lengths s −1 ) at 1.5 wt% H 2 O 2 . Accordingly, the water quality can be monitored by evaluating the movement speed of Cat‐MMSNBs. Moreover, MMSNBs act as a good adsorbent for removing more than 90% of the heavy metal ions with the advantage of the mesoporous structure. In addition, the good magnetic response enables the MMSNBs with precise directional control and is conducive to recycling for repeated operation. This bottom‐up interfacial super‐assembly construction strategy allows for a new understanding of the rational design and synthesis of multi‐functional nanomotors.
An efficient photoelectrochemical aptasensor based on sputtering Au NP-modified nanoporous BiVO4 was rationally designed and fabricated, and it exhibited excellent sensitivity and selectivity for the detection of thrombin with a low detection limit of 0.5 pM.
A hierarchical asymmetric magnetic mesoporous hollow nanorobot was constructed in a sequential interfacial super-assembly strategy. This nanorobot with magnetic responsiveness, confined catalytic degradation, durable motion and recyclability not only sets a platform for manipulating motion behavior, but also provides a promising tool for future applications. More information can be found in the Research Article by B. Kong and co-workers (DOI: 10.1002/chem.202200307).
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