Design Of Nanoreactors Research Articles

Understanding the chemistry of mesostructured porous nanoreactors.

Porous nanoreactors mimic the structures and functions of cells, providing an adaptable material with multiple functions and effects. These reactors can be nanoscale containers and shuttles or catalytic centres, drawing in reactants for cascading reactions with multishelled designs. The detailed construction of multi-level reactors at the nanometre scale remains a great challenge, but to regulate the reaction pathways within a reactor, designs of great intricacy are required. In this Review, we define the basic structural characteristics of porous nanoreactors, while also discussing the design principles and synthetic chemistry of these structures with respect to their emerging applications in energy storage and heterogeneous catalysis. Finally, we describe the difficulties of the structural optimization of these reactors and propose possible ways to improve porous nanoreactor design for future applications.

Designing 2D carbon dot nanoreactors for alcohol oxidation coupled with hydrogen evolution

The coupled green energy and chemical production by photocatalysis represents a promising sustainable pathway, which poses great challenges for the multifunction integration of catalytic systems. Here we show a promising green photocatalyst design using Cu-ZnIn2S4 nanosheets and carbon dots as building units, which enables the integration of reaction, mass transfer, and separation functions in the nano-space, mimicking a nanoreactor. This function integration results in great activity promotion for benzyl alcohol oxidation coupled H2 production, with H2/benzaldehyde production rates of 45.95/46.47 mmol g−1 h−1, 36.87 and 36.73 times to pure ZnIn2S4, respectively, owning to the enhanced charge accumulation and mass transfer according to in-situ spectroscopies and computational simulations of the built-in electrical field. Near-unity selectivity of benzaldehyde is achieved via the effective separation enabled by the Cu(II)-mediated conformation flipping of the intermediates and subsequent π-π conjugation. This work demonstrates an inspiring proof-of-concept nanoreactor design of photocatalysts for coupled sustainable systems.

Quantifying Ultrafast Energy Transfer from Plasmonic Hot Carriers for Pulsed Photocatalysis on Nanostructures.

Photocatalysis with plasmonic nanostructures has lately emerged as a transformative paradigm to drive and alter chemical reactions using light. At the surface of metallic nanoparticles, photoexcitation results in strong near fields, short-lived high-energy "hot" carriers, and light-induced heating, thus creating a local environment where reactions can occur with enhanced efficiencies. In this context, it is critical to understand how to manipulate the nonequilibrium processes triggered by light, as their ultrafast (femto- to picoseconds) relaxation dynamics compete with the process of energy transfer toward the reactants. Accurate predictions of the plasmon photocatalytic activity can lead to optimized nanophotonic architectures with enhanced selectivity and rates, operating beyond the intrinsic limitations of the steady state. Here, we report on an original modeling approach to quantify, with space, time, and energy resolution, the ultrafast energy exchange from plasmonic hot carriers (HCs) to molecular systems adsorbed on the metal nanoparticle surface while consistently accounting for photothermal bond activation. Our analysis, illustrated for a few typical cases, reveals that the most energetic nonequilibrium carriers (i.e., with energies well far from the Fermi level) may introduce a wavelength-dependence of the reaction rates, and it elucidates on the role of the carriers closer to the Fermi energy and the photothermally heated lattice, suggesting ways to enhance and optimize each contribution. We show that the overall reaction rates can benefit strongly from using pulsed illumination with the optimal pulse width determined by the properties of the system. Taken together, these results contribute to the rational design of nanoreactors for pulsed catalysis, which calls for predictive modeling of the ultrafast HC-hot adsorbate energy transfer.

Rational design of silica nanoreactor encapsulated Ni for reinforcing coke-resistance in dry reforming of methane

Dry reforming of methane (DRM) provides a desired approach to produce valuable syngas in tackling greenhouse gases. Yet it faces a formidable challenge in the design and synthesis of high coke-resistant Ni-based catalysts. Herein, we report a nanoreactor strategy to construct a supported Ni catalyst (Ni@SiO2@SiO2) for reinforcing coke-resistance during DRM, by effectively encapsulating small Ni nanoparticles into dendritic fibrous silica (SiO2) nanospheres and coating SiO2 shell layers. Taking advantage of chemical characteristics of citric acid (CA), CA-chelated Ni impregnation enables the uniform immobilization of Ni species into the radial SiO2 framework, then following carbonization produces protective carbon layers on the Ni nanoparticle surface during SiO2 coating, which can be removed via oxidizing calcination. The resultant pomegranate-like nanoreactor catalyst possesses outstanding coke-resistance, without any detectable coke deposition after 200 h of DRM reaction at 700 ℃, benefiting from effectively restricting metal sintering and fully preventing formation of inert carbon species.

Integrating theory with the nanoreactor concept to synthesize hollow carbon sphere‐encapsulated PtNi alloys for enhanced H2 generation

AbstractThe rational design of efficient bimetallic nanoparticle (NP) catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific reaction. Here, we report the rational design of nanoreactors comprising hollow carbon sphere‐confined PtNi bimetallic NPs (PtNi@HCS) as highly efficient catalysts for hydrogen generation via ammonia borane hydrolysis in water. Using both density functional theory calculations and molecular dynamics simulations, the effects of an active PtNi combination and the critical synergistic role of a hollow carbon shell on the molecule diffusion adsorption behaviors are explored. Kinetic isotope effects and theoretical calculations allow the clarification of the mechanism, with oxidative addition of an O–H bond of water to the catalyst surface being the rate‐determining step. The remarkable catalytic activity of the PtNi@HCS nanoreactor was also utilized for successful tandem catalytic hydrogenation reactions, using in situ‐generated H2 from ammonia borane with high efficiency. The concerted design, theoretical calculations, and experimental work presented here shed light on the rational elaboration of efficient nanocatalysts and contribute to the establishment of a circular carbon economy using green hydrogen.

Hollow Zeolite Nanoreactor with Double Shells for Methanol Aromatization: Explicit Recognition on Catalytic Function of Inverse Elemental Zone and Shell-Cavity.

Core@shell catalyst composited of dual aluminosilicate zeolite can effectively regulate the distribution of acid sites to control hydrocarbon conversion process for the stable formation of target product. However, the diffusion restriction reduces the accessibility of inner active sites and affects synergy between core and shell. Herein, hollow ZSM-5 zeolite nanoreactor with inverse aluminum distribution and double shells are prepared and employed for methanol aromatization. It is demonstrated that the intershell cavity alleviated the steric hindrance from zeolites channel and provided more paths and pore entrance for guest molecule. Correspondingly, olefin intermediates generated from methanol over the external shell are easier to adsorb at internal acid sites for further reactions. Importantly, the diffusion of generated aromatic macromolecules to the external surface is also promoted, which slows down the formation of internal coke, and ensures the use of internal acid sites for aromatization. The aromatics selectivity of the nanoreactor remained at 8% after 154h, while that of solid core@shell catalyst decreased to 2% after 75h. This finding promises broader insight to improve internal active site utilization of core@shell catalyst at the diffusion level and can be great aid in the flexible design of multifunctional nanoreactors to enhance the relay efficiency.

Biomimetic metal organic frameworks mediated by metformin and 1-MT for enhancing the synergistic treatment of photodynamic therapy, photothermal therapy and immunotherapy

Design of novel nanoreactor that integrates multiple therapeutic for tumor remains to be challenging. Here, we developed a multiple antitumor nanoreactor, which consisted of biomimetic Metal Organic Framework (Zn/Co-MOF), metformin, cisplatin, indocyanine Green (ICG), 1-methyl-tryptophan (1-MT) and glucose oxidase (GOD) payload, Mxene and AS1411-aptamer decoration. The constructed Nb2C/aptamer-PDA/GOD@Zn/Co-MOF@M/C (NMC) targeted to the tumor cells via AS1411-aptamer, and magnetic Nb2C/aptamer-PDA/ICG@Zn/Co-MOF@1-MT/C (NTC) targeted to the tumor cells via AS1411-aptamer and magnetic effect. In the acidic tumor microenvironment, NMC can consume endogenous glucose to generate the H2O2 and gluconic acid by GOD-mediated reaction and “starved” the tumors. The abundant of H2O2 is catalyzed to generate the oxygen by the Co and singlet oxygen (1O2) by the ICG, which can improved the hypoxic environment of the tumor and effectively reduced the resistance to PDT. The metformin both can block the glycolytic reaction, causing cell apoptosis and reverse tumor immunosuppression through endoplasmic reticulum related PD-L1 degradation to increase immune response. Simultaneously, metformin can hamper O2 consumption and raise the oxygen content of the tumor site to enhance the catalytic efficiency of GOD. The released 1-MT collaborates with metformin can further enhance immune response to produce apparent cytotoxic T cells. Under laser irradiation, the temperature at the tumor site increases sharply and photo-thermal effect can be generated by the Nb2C and ICG, which can lead to the tumor cell apoptosis, achieving significant photo-thermal therapeutic (PTT) effects. The Nb2C can penetrate into the deep tumor tissue due to its small size. The data revealed that joint use of NMC and NTC can trigger immune response, including the enhancement of CD8+ T cells and CD4+ T cells, the production of INF-γ and TNF-α.

Inside Cover: Design of Hollow Nanoreactors for Size‐ and Shape‐Selective Catalytic Semihydrogenation Driven by Molecular Recognition

Inside Cover: Design of Hollow Nanoreactors for Size‐ and Shape‐Selective Catalytic Semihydrogenation Driven by Molecular Recognition

Inside Cover: Design of Hollow Nanoreactors for Size‐ and Shape‐Selective Catalytic Semihydrogenation Driven by Molecular Recognition

Inside Cover: Design of Hollow Nanoreactors for Size‐ and Shape‐Selective Catalytic Semihydrogenation Driven by Molecular Recognition

Design of Hollow Nanoreactors for Size- and Shape-Selective Catalytic Semihydrogenation Driven by Molecular Recognition.

Mimicking the structures and functions of cells to create artificial organelles spurs the development of efficient strategies for producing hollow nanoreactors with biomimetic catalytic functions, but it is still rarely reported because of the highly challenging fabrication. Here, we report the design of hollow nanoreactors with hollow multishelled structure (HoMS) and spatially loaded metal nanoparticles. Starting from molecular-level design strategy, well-defined hollow multishelled structure phenolic resins (HoMS-PR) and carbon (HoMS-C) submicron particles were accurately architected. HoMS-C can serve as an excellent, versatile platform, owing to its tunable properties with tailored functional sites, for achieving precise spatial location of metal nanoparticles, internally encapsulated (Pd@HoMS-C) or externally supported (Pd/HoMS-C). Impressively, the combination of the delicate nanoarchitecture and spatially loaded metal nanoparticles endow the pair of nanoreactors size-shape-selective molecular recognition properties in catalytic semihydrogenation, including high activity and selectivity of Pd@HoMS-C for small aliphatic substrates and Pd/HoMS-C for large aromatic substrates. Theoretic calculation provides insights into the pair of nanoreactors with distinct behaviors due to the differences in energy barrier of substrate adsorption. This work shed the light on rational design and accurate construction of hollow nanoreactors with precise location of active sites and fine-modulated microenvironment by mimicking the functions of cells.

Design of Hollow Nanoreactors for Size‐ and Shape‐Selective Catalytic Semihydrogenation Driven by Molecular Recognition

AbstractMimicking the structures and functions of cells to create artificial organelles has spurred the development of efficient strategies for production of hollow nanoreactors with biomimetic catalytic functions. However, such structure are challenging to fabricate and are thus rarely reported. We report the design of hollow nanoreactors with hollow multishelled structure (HoMS) and spatially loaded metal nanoparticles. Starting from a molecular‐level design strategy, well‐defined hollow multishelled structure phenolic resins (HoMS‐PR) and carbon (HoMS‐C) submicron particles were accurately constructed. HoMS‐C serves as an excellent, versatile platform, owing to its tunable properties with tailored functional sites for achieving precise spatial location of metal nanoparticles, internally encapsulated (Pd@HoMS‐C) or externally supported (Pd/HoMS‐C). Impressively, the combination of the delicate nanoarchitecture and spatially loaded metal nanoparticles endow the pair of nanoreactors with size–shape‐selective molecular recognition properties in catalytic semihydrogenation, including high activity and selectivity of Pd@HoMS‐C for small aliphatic substrates and Pd/HoMS‐C for large aromatic substrates. Theoretical calculations provide insight into the pair of nanoreactors with distinct behaviors due to the differences in energy barrier of substrate adsorption. This work provides guidance on the rational design and accurate construction of hollow nanoreactors with precisely located active sites and a finely modulated microenvironment by mimicking the functions of cells.

Design of competition nanoreactor with shell-isolated colloidal plasmonic nanomaterials for quantitative sensor platform

Shell-isolated colloid plasmonic nanomaterials-based nanoreactor is a well-established platform widely applied in catalyst or Surface Enhanced Raman Scattering (SERS) sensors. The potentials versatility of nanoreactor platform is mainly implemented by the well-defined and tailorable structure of colloid plasmonic nanomaterials. Currently, a competitive conjugative-mediated nanoreactor is introduced to determine glucose with SERS. Glucose-conjugating nanoreactor, as convertors of the sensors, are constructed by coordinated deposition colloidal gold nanoparticles with sodium nitroprusside framework (Au@SNF) and covalently bonded 4-mercaptopyridine (4-Mpy) with self-assembly strategy. The nanoreactor contained the signal-amplifier Au@SNF NPs, conjugative-mediated signal receiver 4-Mpy, and signal internal standard molecular CN−. In addition to well-defined morphology and functionality, conjugative-mediated and internal standards method are also employed to benefit the nanoreactor. The two-parameter strategy significantly improves the signal indication and correction. Using this proposed platform, the competitive-mediated nanoreactor provides a quantitative SERS detection of glucose, and extends the applicability of SERS in more complicated and reproducibility analysis. Meanwhile, the nanoreactor based sensors also exhibited better properties to detect glucose in various food samples and bio-samples which provided strongly appliance for glucose sensors.

Design of enzyme nanoreactor by phase-transitioned lysozyme modified magnetic dendritic silica nanoparticle for efficient catalytic performance at harsh reaction condition

Design of enzyme nanoreactor by phase-transitioned lysozyme modified magnetic dendritic silica nanoparticle for efficient catalytic performance at harsh reaction condition

Design of polymer-based nanoreactors for efficient acid/base cascade catalysis: A comparative study of site isolation strategies

Cascade catalysis carries out two or more consecutive catalytic reactions without separation and purification of intermediate products, which is of great significance in chemical production. Acid/base cascade catalysis in one-pot is widely studied, but it still faces great challenges due to the incompatibility of the two catalysts. In this study, three catalytic systems for acid/base cascade catalysis, the mixture of two separated acid and base micelles, acid and base isolated micelles with/without an intermediate cross-linking layer as catalytic nanoreactors were fabricated by utilizing RAFT polymerization technique respectively. Comparative study of the three site isolation strategies were carried out through investigating their catalytic activities for the deacetalization-Knoevenagel cascade reactions. The results disclosed that intermediate cross-linking layer of core-shell micelle could effectively hamper the contact of acid and base catalysts, presenting good catalytic activities. The study may provide new ideas and fabrication approaches for other cascade catalysis with incompatible catalysts.

Rational Design and Synthesis of 3D Nanoreactors for Green Fuel Production: Design Band Gap Y@DS Photocatalyst under Visible Irradiation

Rational Design and Synthesis of 3D Nanoreactors for Green Fuel Production: Design Band Gap Y@DS Photocatalyst under Visible Irradiation

An efficient bioinspired functional micellar nanoreactor for dephosphorylation reactions

An efficient bioinspired catalytic system for dephosphorylation reactions should combine imidazole reaction sites with a hydrophobic region that favors intimate interaction with the substrate. In this work, we show that the catalytic activity of long-chain alkylimidazoles such as 1-tetradecylimidazole (ImR) that are poorly soluble in aqueous medium is greatly improved by the use of mixed micelles of ImR with cetyltrimethylammonium bromide (CTAB). The size, zeta potential, degree of protonation of ImR and the catalytic activity in dephosphorylation of diethyl 2,4-dinitrophenyl phosphate (DEDNPP) were found to be functions of the CTAB/ImR ratio and the pH of the medium, with optimal catalytic activity at pH 6 and at low CTAB/ImR ratios (3/1 and 2/1). For 3/1 CTAB/ImR, the ImR-catalyzed dephosphorylation of DEDNPP was 9x106-fold faster than the spontaneous hydrolysis of DEDNPP and ca. 102-fold faster than the reaction catalyzed by free imidazole. The same 3/1 CTAB/ImR mixed micelles were also shown to accelerate the dephosphorylation of the pesticide Paraoxon (diethyl 4-nitrophenylphosphate). The relative structural simplicity of the components of these mixed micellar aggregates, combined with the ability to promote significant accelerations of the rates of dephosphorylation reactions, point to mixed micellar aggregates of this type as prototypes for the design of efficient nanoreactors for performing alkylimidazole-catalyzed dephosphorylation reactions.

Photo-Cross-Linking Polymersome Nanoreactors with Size-Selective Permeability

The design of stable, inert, and permeable nanoreactors remains a challenge due to the additives required to create a cross-linked network, limiting their potential for catalysis. Polymersomes are nanovesicles self-assembled from amphiphilic block copolymers that can act as nanoreactors by encapsulating catalysts. A major restriction toward their use is their stability and reduced permeability. In order to overcome this, polymersome membranes can be cross-linked to retain their shape and function. Here, we report the synthesis of a PEG-b-P(S-co-4-VBA) polymer, which can self-assemble into polymersomes and subsequently be cross-linked using UV light. We demonstrate that these polymersomes are stable over a long period of time in various organic solvents, that incorporation of functional handles on their surface is possible, and that they are able to undergo reactions. Additionally, we show that co-assembly with up to 40% PEG-b-PS present results in the formation of pores in the membrane structure, which allows for the structure to be used as a nanoreactor. By encapsulating a platinum nanocatalyst, we are able to catalyze the depropargylation of a small coumarin substrate, which was able to enter and leave the porous nanoreactor.

A Universal Chemical Method for Rational Design of Protein-Based Nanoreactors*.

Self-assembly of a monomeric protease to form a multi-subunit protein complex "proteasome" enables targeted protein degradation in living cells. Naturally occurring proteasomes serve as an inspiration and blueprint for the design of artificial protein-based nanoreactors. Here we disclose a general chemical strategy for the design of proteasome-like nanoreactors. Micelle-assisted protein labeling (MAPLab) technology along with the N-terminal bioconjugation strategy is utilized for the synthesis of a well-defined monodisperse self-assembling semi-synthetic protease. The designed protein is programmed to self-assemble into a proteasome-like nanostructure which preserves the functional properties of native protease.

Molecular Display on Protein Nanocompartments: Design Strategies and Systems Applications

AbstractThe design of biomimetic systems in the laboratory is a long‐sought goal for systems chemists and synthetic biologists alike. Fundamental to this design is the generation of self‐assembled structures capable of mimicking compartmentalisation, which includes the encapsulation of molecular cargo as well as the display of molecules on the exterior. Protein nanocompartments are fast becoming popular scaffolds for these systems due to their robust self‐assembly, ability to encapsulate non‐native cargo, and amenability to surface modifications. In this Review, we discuss the primary methods for displaying a wide array of molecular motifs on compartment surfaces. We discuss benefits and drawbacks of each type of display and examine three recent case studies wherein molecular display was a critical design element in the construction of multi‐enzyme chemical systems. The analyses and case studies presented in this Review aim to provide a critical summary of the technologies currently used for molecular display to add another dimension to the design of chemical systems and nanoreactors.

Atomic Pyridinic Nitrogen Sites Promoting Levulinic Acid Hydrogenations over Double‐Shelled Hollow Ru/C Nanoreactors

Nitrogen-doped nanocarbons are widely used as supports for metal-heterogeneous catalytic conversions. When nitrogen-doped nanocarbon supports are used to disperse metallic nanoparticles (MNPs), the nitrogen dopant can enhance MNPs electron density to reach higher catalytic activity and promote MNPs stability through anchoring effects. However, the precise identification of active nitrogen species between N-dopants and reactants is rarely reported. Herein, a proof-of-concept study on the active N species for levulinic acid hydrogenation is reported. A double-shell structured carbon catalyst (DSC) is designed with selectively locating ultrafine Ru NPs only on inner carbon shell, specifically, different N species on the external carbon shell. Through the design of such a nanostructure, it is demonstrated that the alkaline pyridinic N species on the outer shell serves as an anchor point for the spontaneous binding of the acidic reactant. The pyridinic N content can be modulated from 7.4 to 29.2mg gcat -1 by selecting different precursors. Finally, the Ru-DSC-CTS (using chitosan as the precursor) catalyst achieves a 99% conversion of levulinic acid under 70°C and 4MPa hydrogen pressure for 1 h. This work sheds light on the design of nanoreactors at the atomic scale and investigates heterogeneous catalysis at the molecular level.