Catalytic Nanoreactors Research Articles

Zwitterionic Polyelectrolyte Complex Vesicles Assembled from Homopoly(2-Oxazoline)s as Enzyme Catalytic Nanoreactors for Potent Anti-Tumor Efficiency.

Enzymes are known for their remarkable catalytic efficiency across a wide range of applications. Here, we present a novel and convenient nanoreactor platform based on zwitterionic polyelectrolyte complex vesicles (PCVs), assembled from oppositely charged homopoly(2-oxazoline)s, facilitating enzyme immobilization. We show remarkable enhancements in catalytic activity and stability by encapsulation of lipase as a model enzyme. Even as the temperature rises, the performance of the lipase remains robust. Further, the structural characteristics of PCVs, including hollow architecture and semipermeable membranes, endow them with unique advantages for enzyme cascade reactions involving glucose oxidase (GOx) and horseradish peroxidase (HRP). A decline in catalytic efficiency is shown when the enzymes are individually loaded and subsequently mixed, in contrast to the coloaded GOx-HRP-PCV group. We demonstrate that the vesicle structures establish confined environments where precise enzyme-substrate interactions facilitate enhanced catalytic efficiency. In addition, the nanoreactors exhibit excellent biocompatibility and efficient anti-tumor activity, which hold significant promise for biomedical applications within enzyme-based technologies.

3D-Continuous Nanoporous Covalent Framework Membrane Nanoreactors with Quantitatively Loaded Ultrafine Pd Nanocatalysts.

The confinement effect of catalytic nanoreactors containing metal catalysts within nanometer-sized volumes has attracted significant attention for their potential to enhance reaction rate and selectivity. Nevertheless, unregulated catalyst loading, aggregation, leaching, and limited reusability remain obstacles to achieving an efficient nanoreactor. A robust and durable catalytic membrane nanoreactor prepared by incorporating palladium nanocatalysts within a 3D-continuous nanoporous covalent framework membrane is presented. The reduction of palladium precursor occurs on the pore surface within 3D nanochannels, producing ultrafine palladium nanoparticles (Pd NPs) with their number density adjustable by varying metal precursor concentrations. The precise catalyst loading enables controlling the catalytic activity of the reactor while preventing excess metal usage. The facile preparation of Pd NP-loaded free-standing membrane materials allows hydrodechlorination in both batch and continuous flow modes. In batch mode, the catalytic activity is proportional to the loaded Pd amount and membrane area, while the membrane retains its activity upon repeated use. In continuous mode, the conversion remains above 95% for over 100h, with the reactant solution passing through a single 50µm-thick Pd-loaded membrane. The efficient nanoporous film-type catalytic nanoreactor may find applications in catalytic reactions for small chemical devices as well as in conventional chemistry and processes.

Construction of carbon-doped mesoporous g-C3N4 catalytic nanoreactor via bubble template method for visible-light photocatalysis

Morphological control of photocatalysts is an important way to improve photocatalytic activity. Herein, we design a carbon-doped mesoporous g-C3N4 nanoreactor by combining the self-assembly method of supramolecular precursors with the bubble template method. The mesoporous structure can increase the utilization rate of light absorption. Furthermore, the C atoms replace the position of bridging N atoms may generate delocalized large π bonds, both of which can facilitate photocatalysis. This nanoreactor coupled with larger specific surface area and faster electronic transmission efficiency shows an outstanding performance in photocatalytic RhB degradation (97%, 15 min) and reducing CO2 into CO (60.82 μmol/g, 5h). The C-doped mesoporous g-C3N4 nanoreactor would provide some practical reference for environmental improvements and clean energy production.

Gold Nanoclusters Synthesized within Single-Chain Nanoparticles as Catalytic Nanoreactors in Water.

Metalloenzymes are able to catalyze complex biochemical reactions in cellular (aqueous) media with high efficiency. In recent years, a variety of metal-containing single-chain nanoparticles (SCNPs) have been synthesized as simplified metalloenzyme-mimetic nano-objects. However, most of the metal-containing SCNPs reported so far contained complexed metal ions but not metal nanoclusters (NCs) with diameter <5 nm, which could be used as powerful, emerging catalysts. Herein, we report the synthesis of gold nanoclusters (Au-NCs) within SCNPs and the further use of Au-NCs/SCNPs as catalytic nanoreactors in water. We demonstrate that a common motif contained in several drugs (i.e., the aminophenyl-oxazolidinone fragment present in Rivaroxaban, Sutezolid, and Linezolid) can be efficiently prepared in water from a hydrophobic precursor compound by using the Au-NCs/SCNPs as efficient catalytic nanoreactors. In summary, this work paves the way forthe synthesis of metal-NCs/SCNPs for advanced catalysis in aqueous media.

Catalytic nanoreactors promote GLUT1-mediated BBB permeation by generating nitric oxide for potentiating glioblastoma ferroptosis

Glioblastoma, the most common malignant brain tumor with a poor prognosis, still needs to develop effective therapeutic strategies to prolong the patient’s survival. Inducing GBM tumor cell ferroptosis could be the specific assay to improve GBM therapeutic efficiency. In comparison, ferroptosis in GBM cells is limited by the low intracellular ferrous ion concentration and oxidation resistance. Herein, an MNP-based ferroptosis catalytic nanoreactor loading cisplatin (CMNP-Cis-Arg) was designed to evaluate their targeted delivery and therapeutic efficiency in GBM treatment. The ferroptosis catalytic nanoreactors achieved an effective GBM targeted transportation via chitosan oligosaccharide driven GLUT1-mediated BBB permeabilization and arginine-based tumor chemotactic. CMNP-Cis-Arg improves synergistically lipid oxidation in GBM cells by inducing ROS generation and depleting intracellular GSH. The MNPs elevate ROS levels in tumor cells by enhancing Fe2+-based Fenton reaction and the encapsulated cisplatin as a chemotherapy agent depleting GSH via inducing the DNA strand broken. Moreover, the CMNP-Cis-Arg further induces NO biosynthesis and generates ONOO– with high oxidability to increase lipid oxidation. The anti-GBM ability of the CMNP-Cis-Arg was evaluated both in vitro and in vivo, significantly inducing the GBM tumor cells’ apoptosis and reducing the tumor burden in an orthotopic mouse model. The investigation provided a novel ferroptosis catalytic nanoreactor and confirmed their anti-GBM efficiency in boosting tumor intracellular ferroptosis, suggesting a potential therapeutic strategy worth further investigating preclinically.

Core–shell magnetic zinc-based molecularly imprinted polymer: a robust heterogeneous catalytic nanoreactor toward the CO2 fixation reaction

This study deals with the synthesis of a core–shell magnetic zinc-based molecularly imprinted polymer (M-Zn-MIP) as a robust heterogeneous catalytic nanoreactor. The catalytic activity of the M-Zn-MIP was explored in the CO2 fixation reaction.

Biomineralized in situ catalytic nanoreactor integrated microneedle patch for on demand immunomodulator supply to combat psoriasis.

The endogenous immunomodulator adenosine (ADO) was expected to be potentialized as an efficacious mediator to combat psoriasis. However, its efficacy is severely hindered by its poor metabolic stability and insufficient accumulation at the dermatological lesions. Methods: In this study, a biomineralized in situ catalytic nanoreactor was delicately customized by encapsulating ADO precursor (adenosine monophosphate, AMP) within the internal porous skeleton of zeolitic imidazolate framework-90, followed by the biomineralization of the AMP catabolic enzyme on the outer layer. The nanocrystals were then incorporated into a dissolving microneedles patch, which was designed to deliver drugs with precision into the cutaneous lesion and enhance the efficacy of psoriasis treatment. Results: Upon penetration into the skin, the nanoreactors were released and underwent a gradual collapse of their structure, releasing AMP when exposed to the acidic microenvironment. Meanwhile, the acidic pH could trigger an in situ catalytic reaction to continuously produce ADO. This system yielded remarkable results in a psoriasis-like mouse model. The mechanism study demonstrated that this system could substantially reshape the inflammatory ecosystem by inhibiting the keratinocyte hyperplasia, reducing inflammatory cytokine expression, and regulating the infiltration of immune cells. Conclusion: The in situ catalytic nanoreactor integrated microneedle patch is a promising modular platform for co-delivery of prodrugs and their catabolic enzymes, offering a potential solution for various diseases.

Overlooked role of void-nanoconfined effect in emerging pollutant degradation: Modulating the electronic structure of active sites to accelerate catalytic oxidation

The efficient removal of emerging pollutant from water is the ultimate frontiers of advanced oxidation processes (AOPs), yet it is challenging to obtain higher catalytic activity and oxidation rate. Herein, a sustainable solution was proposed by optimizing the curvature of confined structure to modulate the electronic state of the active sites in nanochannels for improving the catalytic activity. In addition, the confined effect can enhance the oxidation rate by shorting the mass transfer of active species and pollutants. A void-nanoconfined nanoreactor was prepared by loading Fe2O3 into the nanochannels (<5 nm) of the hollow carbon sphere. An enhancement of 3 orders of magnitude was obtained in the degradation rate constant of void-nanoconfined catalytic system toward sulfamethoxazole (SMX) (6.25 min−1) compared with the non-confined system. The kinetics enhancement was attributed to the larger electron potential difference between the outer and inner nanochannel caused by the curvature increase of carbon sphere, accelerating the electron transfer, so that the energy barrier of SMX degradation reaction was reduced by 31 kcal/mol with the assistance of confinement energy. Importantly, the NC-IN/PDS system exhibited outstanding removal efficiency for the actual river water using a continuous flow reactor. This work provides a new insight into designing an efficient and stable catalytic nanoreactor, enriching the domain of advanced wastewater treatment strategies.

Pd nanoparticles embedded in nanolignin (Pd@LNP) as a water dispersible catalytic nanoreactor for Cr(VI), 4-nitrophenol reduction and C[sbnd]C coupling reactions

The use of water-dispersible and sustainable Pd nanocatalysts to reduce toxic heavy metal ions and catalyze important organic reactions has profound significance for the environmental remediation and the catalytic industry. In this work, a novel water-dispersible and recyclable Pd@LNPs nanoreactor composed of Pd nanoparticle cluster core and LNPs shell was developed in microwave reactor in aqueous solution. It turned out that Pd nanoparticles grew uniformly and stably inside LNPs nanosphere due to the coordinated binding and interaction between Pd and the functional groups in LNPs, which was significantly different from surface loading. The green and biodegradable LNPs nanospheres are not only used as reducing agents for Pd (II) and nanocarriers, but also act as individual nanocontainers to provide favorable sites for reactions and effectively control the entry and release of reactants and products. Furthermore, the excellent and efficient catalytic properties of Pd@LNPs were exhibited by CC coupling reactions and the reduction of Cr(VI) and 4-nitrophenol. The Pd@LNPs prepared in this study have the advantages of excellent dispersion, great recyclability, high turnover frequency and better green sustainability metrics. It will have a great significance for the development of the potential high-value of lignin and the progress in the field of bio-nanocatalysts.

Sub-micro- and nano-sized polyethylene terephthalate deconstruction with engineered protein nanopores

The identification or design of biocatalysts to mitigate the accumulation of plastics, including sub-micro- and nano-sized polyethylene terephthalate (nPET), is becoming a global challenge. Here we computationally incorporated two hydrolytic active sites with geometries similar to that of Idionella sakaiensis PET hydrolase, to fragaceatoxin C (FraC), a membrane pore-forming protein. FraCm1/m2 could be assembled into octameric nanopores (7.0 nm high × 1.6–6.0 nm entry), which deconstructed (40 °C, pH 7.0) nPET from GoodFellow, commodities and plastic bottles. FraCm1 and FraCm2 degrade nPET by endo- and exo-type chain scission. While FraCm1 produces bis(2-hydroxyethyl) terephthalate as the main product, FraCm2 yields a high diversity of oligomers and terephthalic acid. Mechanistic and biochemical differences with benchmark PET hydrolases, along with pore and nPET dynamics, suggest that these pore-forming protein catalytic nanoreactors do not deconstruct macro-PET but are promising in nanotechnology for filtering, capturing and breaking down nPET, for example, in wastewater treatment plants.

Construction of S-scheme heterojunction catalytic nanoreactor for boosted photothermal-assisted photocatalytic H2 production

Reasonable design of heterojunction band structure and strengthening of the photothermal effect is an important method to promote the photothermal-assisted photocatalytic H2 production activity of photocatalysts. Herein, a composite material named as Co3O4/CNNVs S-scheme heterojunction nanoreactor was constructed by loading Co3O4 nanoparticles on the surface of g-C3N4 nanovesicles (CNNVs) through a simple hydrothermal method and used to achieve efficient photothermal-assisted photocatalytic H2 production. In the absence of Pt as a cocatalyst, Co3O4/CNNVs-22.5 exhibited a photocatalytic H2 production rate up to 772.9 μmol g-1h−1 under irradiation with a 300 W Xenon lamp, which is much higher than that of pure CNNVs (15.5 μmol g-1h−1). In the Co3O4/CNNVs photothermal-assisted photocatalytic system, the synergistic effect of the strong photothermal effect of Co3O4 nanoparticles and the thermal insulation effect of hollow CNNVs nanoreactor was shown to be the main reasons for promoting the surface temperature increase of the heterojunction photocatalyst, which effectively facilitates the separation and transfer of photo-generated carriers, thus increasing the photocatalytic H2 production. In addition, the S-scheme heterojunction formed between Co3O4 and CNNVs optimize the charge transfer path. This work presents a reasonable design of highly efficient photocatalyst with a S-scheme heterojunction nanoreactor for the photothermal-assisted photocatalysis.

Electrochemical oxidation of phenol in a PtRu/NbC membrane-based catalytic nanoreactor

Electrochemical oxidation has attracted growing attention to treat organic in wastewater. However, achieving a high reactor efficiency and harmless treatment of the toxic organics is still a significant challenge. In this work, the bimetal Pt and Ru were firstly co-electrodeposited on the surface of nanoporous niobium carbide (NbC) membranes (∼8.3 nm pore size) applying for anode in flow-through reactor for phenol electrochemical oxidation. In a continuous flow-through reactor, the single-pass removals of phenol and chemical oxygen demand (COD) were 99.7 % and 74.2 %, respectively, with a short hydraulic retention time of 342 s, demonstrating rapid phenol degradation that is an order of magnitude shorter than those reported in other studies. This excellent reactor efficiency was ascribed to a large interfacial reaction area providing by the pollutant phase-catalytic membrane-green product phase. We compared the mass transfer of flow-through and flow-by reactor testifying the high efficiency of flow-through reactor. The excellent stability of PtRu/NbC anode enable this reactor to operate 50 h stably. Moreover, the presence of low or non-toxic (catechol and acetic acid) as the residues of phenol degradation resulting from the contribution of synergistic reaction between direct and indirect oxidation process.

A closed-loop catalytic nanoreactor system on a transistor.

Precision chemistry demands miniaturized catalytic systems for sophisticated reactions with well-defined pathways. An ideal solution is to construct a nanoreactor system functioning as a chemistry laboratory to execute a full chemical process with molecular precision. However, existing nanoscale catalytic systems fail to in situ control reaction kinetics in a closed-loop manner, lacking the precision toward ultimate reaction efficiency. We find an inter-electrochemical gating effect when operating DNA framework-constructed enzyme cascade nanoreactors on a transistor, enabling in situ closed-loop reaction monitoring and modulation electrically. Therefore, a comprehensive system is developed, encapsulating nanoreactors, analyzers, and modulators, where the gate potential modulates enzyme activity and switches cascade reaction "ON" or "OFF." Such electric field-effect property enhances catalytic efficiency of enzyme by 343.4-fold and enables sensitive sarcosine assay for prostate cancer diagnoses, with a limit of detection five orders of magnitude lower than methodologies in clinical laboratory. By coupling with solid-state electronics, this work provides a perspective to construct intelligent nano-systems for precision chemistry.

Incorporation of Heteroatomic Fe Activates Rapid Catalytic Behaviors of Co3O4 Hollow Nanoplates Toward Advanced Lithium–Sulfur Batteries

AbstractLithium–sulfur (Li–S) battery is a highly attractive energy storage system due to its high capacity and great affordability. However, the parasitic shuttle effect and sluggish redox kinetics are perplexing the fulfillment of efficient battery electrochemistry. To tackle these challenges, herein, a hierarchical and hollow nanoplate assembled by Fe‐doped Co3O4 nanosheets (Fe–Co3O4 HHNPs) is meticulously designed as an advanced sulfur nanoreactor. The interlaced nanosheets establish a robust and porous network for fast charge transfer and efficient active site exposure. More importantly, the heteroatomic Fe incorporation tailors the electronic structure via local structure distortion and electron redistribution, contributing to massive active sites that lower the energy barrier for sulfur conversions. The resulting sulfur adsorption and catalyzation endow the Li–S cells with minimum capacity decay of 0.08% per cycle over 500 cycles and decent rate performance up to 5 C. Moreover, a high areal capacity of 9.0 mAh cm−2 after 55 cycles is also achievable under raised sulfur loading of 11 mg cm−2 and limited electrolyte (E/S = 3.9 µL mg−1). This work provides an elaborate and instructive paradigm for designing catalytic nanoreactors toward superior Li–S electrochemistry.

Nanoreactor Engineering Can Unlock New Possibilities for CO2 Tandem Catalytic Conversion to C-C Coupled Products.

Climate change is becoming increasingly more pronounced every day while the amount of greenhouse gases in the atmosphere continues to rise. CO2 reduction to valuable chemicals is an approach that has gathered substantial attention as a means to recycle these gases. Herein, some of the tandem catalysis approaches that can be used to achieve the transformation of CO2 to C-C coupled products are explored, focusing especially on tandem catalytic schemes where there is a big opportunity to improve performance by designing effective catalytic nanoreactors. Recent reviews have highlighted the technical challenges and opportunities for advancing tandem catalysis, especially highlighting the need for elucidating structure-activity relationships and mechanisms of reaction through theoretical and in situ/operando characterization techniques. In this review, the focus is on nanoreactor synthesis strategies as a critical research direction, and discusses these in the context of two main tandem pathways (CO-mediated pathway and Methanol-mediated pathway) to C-C coupled products.

Fe-Ni bimetallic nanoparticles encapsulated into nanofibrous carbon microspheres as a catalytic nanoreactor for highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran or 2,5-dihydroxymethyltetrahydrofuran

BackgroundThe highly efficient conversion of renewable biomass-derived platform compounds to high value-added chemicals is one of the most promising solution to the current rapid consumption of fossil resources. MethodsNanofibrous and porous carbon microspheres (NPCMs) were developed from chitin biomass and used to encapsulate Fe-Ni bimetallic nanoparticles for the formation of a novel catalytic nanoreactor (Fe-Ni/NPCMs), which was then used for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) or 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Significant findingsThe NPCMs consisted of N-doped carbon nanofibers with a high surface area. The Fe-Ni bimetallic nanoparticles were uniformly dispersed on the carbon nanofiber surfaces of the Fe-Ni/NPCMs, resulting in abundant catalytic sites and excellent catalytic performance. Importantly, the Fe-Ni/NPCMs showed highly-selective hydrogenation of HMF to DHMF or DHMTHF with high yields of 93.6% or 94.9% through simply modulating the reaction conditions. Increasing the zero valent iron (Fe0) content in the Fe-Ni/NPCMs significantly promoted the DHMTH selectivity from HMF hydrogenation. Moreover, the Fe-Ni/NPCMs presented high stability and recyclability, and thus they are applicable to other biomass conversions. Therefore, Fe-Ni/NPCMs have promising industrial application in the production of high value-added chemicals from biomass-derived feed-stocks.

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.

Poly(ethylene imine) stabilized metal hydroxide nanoaggregates in reverse microemulsion system enabling synthesis of hollow silica catalytic nanoreactors as highly efficient semihydrogenation catalysts

In this work, we report a generic method of reverse microemulsion for syntheses of uniform and well-dispersed hollow porous silica nanospheres with metal (oxide) nanoparticles inside their cavities (MxOy@HPSNs or M@HPSNs), where the water phase consists of poly(ethylene imine) stabilized metal hydroxide nanoaggregates. During silica deposition, the mentioned nanoaggregates function as void templates as well as a platform to deliver catalytic functionality into voids. The subsequent calcination simultaneously gives hollow nanostructures and metal (oxide) nanoparticles inside central voids. The method applies to the metals that have hydroxide precipitates at basic conditions, and is suitable for most of catalytically active metals. As a demonstration, Pd@HPSNs illustrate high catalytic efficiency for selective hydrogenation of phenylacetylene at ambient H2 pressure, and the enhancement could be assigned to the effect of void confinement.

Thermo-responsive polymer-based catalytic nanoreactors for controllable catalysis of selective oxidation of alcohols in water

The study showcases a thermo-responsive polymer-based nanoreactor for controllable catalysis by “opening” and “closing” of the transport channel of water-soluble reactants.

Hollow and mesoporous M@aluminosilicate (M = Rh, Pd and Pt) bifunctional catalytic nanoreactors for the hydrodeoxygenation of lignin-derived phenols

The high hydrodeoxygenation activity of Rh@Al2.0–mSiO2 could be attributable to the synergistic effect between the metallic Rh and Lewis and Brønsted acid sites.