Hybrid Nanocrystals Research Articles

Flow synthesis of photocatalytic semiconductor-metal hybrid nanocrystals.

Semiconductor-metal hybrid nanostructures are promising materials for photocatalytic applications, providing high efficiencies compared to their composing counterparts. So far, the synthesis of such hybrid nanoparticles was limited to batch reactors, achieving tunability while demonstrating how each of the nanocrystals' characteristics affects photocatalytic performances. Yet, new methodologies should be established to increase the synthetic yield while maintaining high control over the resulting structures. Herein, scalable advanced flow techniques are introduced, yielding ZnSe-metal hybrid nanoparticles either in a thermal growth or photo-induced growth regime. Firstly, thermal gold growth in the flow reactor is achieved with good control over the metal tip size and the nanoparticle morphology. We address the dependence of the reaction on temperature, the precursor to nanorod molar ratios, and additional parameters. Additionally, light-induced growth by the flow reactor is demonstrated for platinum clusters. The quality of the resulting hybrids is directly demonstrated by their functionality in photocatalytic hydrogen generation by water reduction, displaying enhanced activity compared to bare ZnSe nanorods. The fairly straightforward adaptation of such powerful flow-reaction techniques to scale-up photocatalytic hybrid nanoparticle syntheses takes them one step forwards towards the realization of their potential in real-life application scenarios.

Carboxylation Using Carbon Dioxide by Co-Immobilized Enzyme-Inorganic Hybrid Nanocrystal

Carboxylation Using Carbon Dioxide by Co-Immobilized Enzyme-Inorganic Hybrid Nanocrystal

Ingenious ambient temperature fabrication zirconium-metal organic framework laden polysaccharide aerogel as an efficient glyphosate scavenger

Developing superior adsorbents to remove pollutants from aqueous solution is increasingly becoming urgent with respect to grave water pollution and public health consequences. Herein, a metal organic framework (MOFs)-decorated shapeable aerogel (CS-CNC@UiO-66-NH2) prepared by in situ growth of Zr-MOF (UiO-66-NH2) on chitosan/cellulose nanocrystal (CS-CNC) hybrid aerogel at room temperature was developed to remove glyphosate (Gly) from water. The aerogel possessed highly porous structure and excellent water stability upon introduction of cellulose nanocrystals extracted from cotton. Besides, the loading ratio of UiO-66-NH2 of the proposed ambient growth strategy (37.72%) was higher than conventional solvothermal method (10.91%) because of the structure integrity of polysaccharide aerogels at room temperature. Further, the BET area and porosity of CS-CNC@UiO-66-NH2 aerogel increased from 21.65 m2 g−1 to 231.60 m2 g−1 and 87.47–93.03% due to the synergy of UiO-66-NH2. Owing to these virtues, the separation-free aerogel exhibited a high adsorption capacity of 133.7 mg/g in batch adsorption and displayed high recyclability over four consecutive adsorption-desorption cycles. Moreover, the Zr-OH/oxygen-containing moieties of the aerogel, electrostatic attraction and hydrogen-bonding accounted for driving Gly adsorption. Considering practical application, the aerogels were packed in glass column for fixed-bed test which revealed that the aerogels could decontaminate Gly with column adsorption capacity of 44.99 mg/g. Consequently, the CS-CNC@UiO-66-NH2 aerogel with highly porous structure exhibited good Gly adsorption and simple separation, offering a novel strategy to synchronously improve adsorption capacity of polysaccharide-based adsorbent and MOFs shaping for pollutant removal.

Dimensionality Control of Inorganic and Hybrid Perovskite Nanocrystals by Reaction Temperature: From No-Confinement to 3D and 1D Quantum Confinement.

This work focuses on the systematic investigation of the shape, size, and composition‐controlled synthesis of perovskite nanocrystals (NCs) under inert gas‐free conditions and using pre‐synthesized precursor stock solutions. In the case of CsPbBr3 NCs, we find that the lowering of reaction temperature from ∼175 to 100 °C initially leads to a change of morphology from bulk‐like 3D nanocubes to 0D nanocubes with 3D‐quantum confinement, while at temperatures below 100 °C the reaction yields 2D nanoplatelets (NPls) with 1D‐quantum confinement. However, to our surprise, at higher temperatures (∼215 °C), the reaction yields CsPbBr3 hexapod NCs, which have been rarely reported. The synthesis is scalable, and their halide composition is tunable by simply using different combinations of precursor solutions. The versatility of the synthesis is demonstrated by applying it to relatively less explored shape‐controlled synthesis of FAPbBr3 NCs. Despite the synthesis carried out in the air, both the inorganic and hybrid perovskite NCs exhibit nearly‐narrow emission without applying any size‐selective separation, and it is precisely tunable by controlling the reaction temperature.

Dimensionality Control of Inorganic and Hybrid Perovskite Nanocrystals by Reaction Temperature: From No‐Confinement to 3D and 1D Quantum Confinement

AbstractThis work focuses on the systematic investigation of the shape, size, and composition‐controlled synthesis of perovskite nanocrystals (NCs) under inert gas‐free conditions and using pre‐synthesized precursor stock solutions. In the case of CsPbBr3 NCs, we find that the lowering of reaction temperature from ∼175 to 100 °C initially leads to a change of morphology from bulk‐like 3D nanocubes to 0D nanocubes with 3D‐quantum confinement, while at temperatures below 100 °C the reaction yields 2D nanoplatelets (NPls) with 1D‐quantum confinement. However, to our surprise, at higher temperatures (∼215 °C), the reaction yields CsPbBr3 hexapod NCs, which have been rarely reported. The synthesis is scalable, and their halide composition is tunable by simply using different combinations of precursor solutions. The versatility of the synthesis is demonstrated by applying it to relatively less explored shape‐controlled synthesis of FAPbBr3 NCs. Despite the synthesis carried out in the air, both the inorganic and hybrid perovskite NCs exhibit nearly‐narrow emission without applying any size‐selective separation, and it is precisely tunable by controlling the reaction temperature.

Highly Luminescent and Phase-Stable Red/NIR-Emitting All-Inorganic and Hybrid Perovskite Nanocrystals

Highly Luminescent and Phase-Stable Red/NIR-Emitting All-Inorganic and Hybrid Perovskite Nanocrystals

Surface lattice engineering for fine-tuned spatial configuration of nanocrystals

Hybrid nanocrystals combining different properties together are important multifunctional materials that underpin further development in catalysis, energy storage, et al., and they are often constructed using heterogeneous seeded growth. Their spatial configuration (shape, composition, and dimension) is primarily determined by the heterogeneous deposition process which depends on the lattice mismatch between deposited material and seed. Precise control of nanocrystals spatial configuration is crucial to applications, but suffers from the limited tunability of lattice mismatch. Here, we demonstrate that surface lattice engineering can be used to break this bottleneck. Surface lattices of various Au nanocrystal seeds are fine-tuned using this strategy regardless of their shape, size, and crystalline structure, creating adjustable lattice mismatch for subsequent growth of other metals; hence, diverse hybrid nanocrystals with fine-tuned spatial configuration can be synthesized. This study may pave a general approach for rationally designing and constructing target nanocrystals including metal, semiconductor, and oxide.

Preparation and photocatalytic performance of CdS@Bi2WO6 hybrid nanocrystals

The hybrid nanocrystals of cadmium sulfide (CdS) and bismuth tungstate (Bi2WO6) (CdS@Bi2WO6) were well-prepared in the nanoreactors of Bi2WO6-contained sodium polyacrylate (PAANa) latex particles, by means of cadmium sulfate/sodium sulfide (CdSO4/Na2S) solutions absorption and solvothermal treatment. The influences of CdSO4/Na2S millimolar ratio on structure and photocatalytic performance of hybrid nanocrystals were investigated. With 3:1 of Cd2+/S2- millimolar ratio in feeding, CdS nanorods on the surface of Bi2WO6 cluster were obtained and its length increased after solvothermal treating; the resultant CdS@Bi2WO6 degraded 96.1% of RhB after illuminating for 120 min, which was more effective than others. With the 1:2 or 1:3 of Cd2+/S2- millimolar ratio, the solvothermal treated cubic-CdS were agglomerated to cluster which attached on the surface of Bi2WO6 cluster, and the agglomerates size increased accordingly. The photocatalytic mechanism suggests that the superoxide ions and holes were the active species produced by CdS@Bi2WO6 in the photocatalytic process. The grown CdS nanorods on the surface of Bi2WO6 had better charge separation ability than the grown CdS clusters on the surface of Bi2WO6. The CdS@Bi2WO6 hybrid nanocrystal with the definite-designed structure will possess the excellent photocatalytic performance.

Light Induced Processes in CsPbBr3–Au Hybrid Nanocrystals: Electron Transfer and Expulsion of Au

Light Induced Processes in CsPbBr₃–Au Hybrid Nanocrystals: Electron Transfer and Expulsion of Au

Nanospheres self-assembled by hybrid oxide nanocrystal and their photoelectric properties

The hybrid nanocrystals of zinc oxide (ZnO), cadmium oxide (CdO) and copper oxide (CuO) were self-assembled to the nanospheres with special structure in the process of inverse Pickering miniemulsion. The 3-(methacryloxy) propyltrimethoxysilane (MPS) was used to modify the crystalline nanoparticles to obtain the partial hydrophobicity on their surfaces. The influences of the dosage ratio of MPS to the crystalline nanoparticles on the size distribution and surface hydrophobicity of modified nanoparticles were discussed. The modified ZnO, CdO and CuO nanocrystals as solid emulsifiers were self-assembled into four kind structure of nanospheres by inverse Pickering miniemulsion. The dosage usage, the three-phase contact angle and their initial dispersion positions of the modified nanocrystals codetermined the structure of hybrid oxide nanocrystals. The nanospheres of hybrid oxide nanocrystal will be successfully prepared by inverse Pickering miniemulsion; they provide the distinctively photoelectric properties.

Development of a Hybrid Bioinorganic Nanobiocatalyst: Remarkable Impact of the Immobilization Conditions on Activity and Stability of β-Galactosidase.

Hybrid bioinorganic biocatalysts have received much attention due to their simple synthesis, high efficiency, and structural features that favor enzyme activity and stability. The present work introduces a biomineralization strategy for the formation of hybrid nanocrystals from β-galactosidase. The effects of the immobilization conditions were studied, identifying the important effect of metal ions and pH on the immobilization yield and the recovered activity. For a deeper understanding of the biomineralization process, an in silico study was carried out to identify the ion binding sites at the different conditions. The selected β-galactosidase nanocrystals showed high specific activity (35,000 IU/g biocatalyst) and remarkable thermal stability with a half-life 11 times higher than the soluble enzyme. The nanobiocatalyst was successfully tested for the synthesis of galacto-oligosaccharides, achieving an outstanding performance, showing no signs of diffusional limitations. Thus, a new, simple, biocompatible and inexpensive nanobiocatalyst was produced with high enzyme recovery (82%), exhibiting high specific activity and high stability, with promising industrial applications.

Tuning Facets and Controlling Monodispersity in Organic–Inorganic Hybrid Perovskite FAPbBr3 Nanocrystals

Lead halide hybrid perovskite nanocrystals are considered as one of the most efficient light-harvesting materials in current research. However, unlike all-inorganic perovskite nanocrystals, the quality optimization and synthetic progress for facet tuning of these hybrid nanocrystals have not moved forward at the same pace. To meet the current demand for high-quality, facet-tuned, and monodisperse nanocrystals, herein, surface A-site cations’ population-controlled facet tuning of FAPbBr3 nanocrystals is reported. Using specific alkylammonium ligands obtained from α-bromo ketones and comparing their concentration with FA+, cubic, dodecahedral, and quasi-spherical shapes of nanocrystals in cubic phase are obtained having monodispersity comparable to that of their best reports. In addition, upon changing of surface ligands, spontaneous formation of self-assembled blue-emitting platelets was also observed. Because of the importance of these materials, these findings will aid the fundamental understanding of formation of hybrid perovskite nanocrystals and also support accelerating their widespread applications.

Adsorption performance of reduced graphene-oxide/cellulose nano-crystal hybrid aerogels reinforced with waste-paper extracted cellulose-fibers for the removal of toluene pollution

In recent years, with the progressive advancement of industries, an enormous amount of polluted effluent has been generated and discharged into the ecosystem. Thus, the aqueous environment has been affected by various kinds of pollution, which threatened the health of living organisms, especially human. Numerous procedures have been developed to eliminate the pollution from the environment, among which the adsorption has been known as an effective method. Up to this point, activated carbon was commercially available as an adsorbent for wastewater treatment. Lately, 3-Dimensional (3D) porous structures, such as Graphene Aerogels (GA) demonstrated supreme potentials of an ideal adsorbent, which introduced the next generation of carbonaceous adsorbents. Herein, we proposed a method based on a mild chemical reduction route to prepare reduced Graphene-Oxide (rGO)/Cellulose Nano-Crystal (CNC) hybrid aerogels. Cellulose Fibers (CFs) extracted from waste-papers were incorporated into the pore-structure as reinforcing agents. Moreover, CNCs were employed to enhance the mechanical stability of rGO sheets, resulting in a 280% increase in the compressive strength of the aerogels. Adsorption performance of the synthesized aerogels, according to ASTM F726-17, exhibited an adsorption capacity of 59 g g−1 for toluene uptake. Besides, the batch adsorption experiments confirmed the pseudo-second-order and Langmuir isotherms as the best-fitted models to explain the adsorption behavior of the adsorbent. The Langmuir isotherm revealed the maximum adsorption capacity of 454 mg g−1 for the removal of toluene from aqueous media. The study showed promising results for graphene-based aerogels to act as the new class of adsorbents.

Highly Effective Self-Propagating Synthesis of Lamellar ZnO-Decorated MnO2 Nanocrystals with Improved Supercapacitive Performance.

A series of MOx (M = Co, Ni, Zn, Ce)-modified lamellar MnO2 electrode materials were controllably synthesized with a superfast self-propagating technology and their electrochemical practicability was evaluated using a three-electrode system. The results demonstrated that the specific capacitance varied with the heteroatom type as well as the doping level. The low ZnO doping level was more beneficial for improving electrical conductivity and structural stability, and Mn10Zn hybrid nanocrystals exhibited a high specific capacitance of 175.3 F·g−1 and capacitance retention of 96.9% after 2000 cycles at constant current of 0.2 A·g−1. Moreover, XRD, SEM, and XPS characterizations confirmed that a small part of the heteroatoms entered the framework to cause lattice distortion of MnO2, while the rest dispersed uniformly on the surface of the carrier to form an interfacial collaborative effect. All of them induced enhanced electrical conductivity and electrochemical properties. Thus, the current work provides an ultrafast route for development of high-performance pseudocapacitive energy storage nanomaterials.

Synthesis of hybrid Au-Ag2S-Cu2-xS nanocrystals with disparate interfacial features

Hybrid nanocrystals (NCs) with multiple components and junctions have attracted considerable attention due to their promising synergistic properties. In particular, great attention has been paid to the manipulation of buried multijunction heterointerfaces because they are closely related to the surface energy and carrier transfer of NCs. However, heterointerfaced NCs are usually constructed by sequential step-by-step pathways, and buried interfaces can only be formed along a given direction, resulting in the one and only spatial orientation of multiple interfaces. In this work, we demonstrate two types of Au-Ag2S-Cu2-xS NCs with disparate interfacial features. Specifically, the first type (Type I) is prepared through a routine two-step method and shows that Au domain close to the Ag2S-Cu2-xS interface; another type (Type II) is achieved by a facile one-pot synthesis procedure and contains Au domain with an interphase only with the Ag2S domain, far from the Cu2-xS domain. More importantly, type II NCs could not be formed through other traditional strategies and an underlying mechanism of formation is developed by monitoring the evolution process. Au@Ag core–shell NCs, metastable Au@Ag2S NCs and Janus Au-Ag2S NCs are formed successively before the Cu2-xS domain appears. We speculate that the Au@Ag2S intermediate plays an essential role in building the final complex nanostructure. We expect that such a simple and facile one-pot method will be used to fabricate additional asymmetric multicomponent NCs with distinctive interfacial features and promising potential applications.

Natural Rubber Latex Reinforced by Graphene Oxide/Zwitterionic Chitin Nanocrystal Hybrids for High-Performance Elastomers without Sulfur Vulcanization

Natural rubber (NR) demonstrates excellent mechanical strength and tensile elasticity after vulcanization. However, the sulfur curing system will generate many problems, including the usage of toxi...

Copper Nanocrystal Morphology Determines the Viability of Molecular Surface Functionalization in Tuning Electrocatalytic Behavior in CO2 Reduction.

Molecular surface functionalization of metallic catalysts is emerging as an ever-developing approach to tuning their catalytic performance. Here, we report the synthesis of hybrid catalysts comprising copper nanocrystals (CuNCs) and an imidazolium ligand for the electrochemical CO2 reduction reaction (CO2RR). We show that this organic modifier steers the selectivity of cubic CuNCs toward liquid products. A comparison between cubic and spherical CuNCs reveals the impact of surface reconstruction on the viability of surface functionalization schemes. Indeed, the intrinsic instability of spherical CuNCs leads to ejection of the functionalized surface atoms. Finally, we also demonstrate that the more stable hybrid nanocrystal catalysts, which include cubic CuNCs, can be transferred into gas-flow CO2RR cells for testing under more industrially relevant conditions.

Cocrystallization-like strategy for the codelivery of hydrophobic and hydrophilic drugs in a single carrier material formulation

Codelivery of drugs by drug carriers is a promising strategy against several diseases such as infections and cancer. However, traditional drug carriers are typically characterized by low drug payload, limiting their treatment efficacy. Using nanocrystals of insoluble drug as carriers, a carrier free platform was developed previously to deliver a second insoluble drug for codelivery. To extend the concept, we hypothesized, herein, that the platform allows for codelivery of hydrophobic and hydrophilic drugs using a cocrystalization-like strategy. To obtain proof-of-concept, paclitaxel (PTX), an insoluble chemotherapeutic agent, and dichloroacetic acid (DCA), a water-soluble inhibitor of pyruvate dehydrogenase kinase, were utilized as model drugs. PTX-DCA hybrid nanocrystals (PTX-DCA NCs) were prepared by anti-solvent precipitation and characterized. Their in vitro antitumor activity against cancer cells was evaluated. PTX-DCA NCs prepared from the optimized formulation had a diameter of 160 nm and a rod-shape morphology and possessed encapsulated efficacy of approximately 30% for DCA. The use of the hybrid crystals enabled synergy to kill cancer cells, in particular in PTX-resistant cells in a dose-dependent pattern. In conclusion, by using a cocrystalization-like strategy, a hydrophilic drug can be formulated into a drug’s nanocrystal for codelivery.

Stable and ultraviolet-enhanced broadband photodetectors based on Si nanowire arrays-Cs3Cu2I5 nanocrystals hybrid structures

Silicon has been the most widely used material for broadband photodetectors. However, the weak response in ultraviolet (UV), especially in deep-UV region, and the large dark current are still their critical drawbacks for practical applications. In this study, a strategy of decorating Cs3Cu2I5 nanocrystals (NCs) on Si nanowire arrays (NWAs) to form a hybrid structure was proposed to overcome the above two issues. Because of the wide and direct bandgap of Cs3Cu2I5 with intrinsic UV light absorption, the photodetection ability of the hybrid detector in UV region was substantially enhanced owing to the efficient down-conversion of the UV incident light. Moreover, driven by a designed Schottky junction from asymmetric electrodes, the hybrid detector can be operated without external power supply. Typically, at 265 nm light excitation, the Si NWA-Cs3Cu2I5 NCs hybrid device achieved a high photoresponsivity of 83.6 mA W−1, a specific detectivity of 2.1 × 1012 Jones, and a large on/off ratio of 3.72 × 103 at 0 V, nearly 350 times higher than the bare Si NWA device. More importantly, the unencapsulated photodetector demonstrates an outstanding operational stability over the aging test for 10 h, and can endure a high humidity (75%, 7 days) and a long-term storage for 300 days in air ambient. Since the different deep-UV light sensitivity of the devices modified with/without Cs3Cu2I5 NCs, a monolithically deep-UV light recognition system was therefore fabricated. It is anticipated that the present strategy provides a new avenue for the preparation of UV-enhanced broadband photodetectors, opening up opportunities for development of integrated optoelectronic systems in the future.

Incorporation of Cellulose Nanocrystals into Graphene Oxide Membranes for Efficient Antibiotic Removal at High Nutrient Recovery

Two-dimensional (2D) material-based membranes hold great promise in wastewater treatment. However, it remains challenging to achieve highly efficient and precise small molecule/ion separation with pure 2D material-fabricated lamellar membranes. In this work, laminated graphene oxide (GO)-cellulose nanocrystal (CNC) hybrid membranes (GO/CNC) were fabricated by taking advantages of the unique structures and synergistic effects generated from these two materials. The characterization results in physiochemical properties, and the structure of the as-synthesized hybrid membranes displayed enhanced membrane surface hydrophilicity, enhanced crumpling surface structure, and slightly enlarged interlayer-spacing with the incorporation of CNCs. Water permeability increases by two to four times with the addition of different CNC weight ratios in comparison to a pristine GO membrane. The optimal GO/CNC membrane achieved efficient rejection toward three typical antibiotics at 74.8, 90.9, and 97.2% for sulfamethoxazole (SMX), levofloxacin (Levo), and norfloxacin (Nor), respectively, while allowing a high passage of desirable nutrients such as NO3- and H2PO4-. It was found that SMX removal is primarily governed by electrostatic repulsion, while adsorption plays a crucial role in removing Levo and Nor. Moreover, the density functional theory calculations confirmed the increased antibiotic removal in the presence of an organic foulant, humic acid. Such a 2D material-based hybrid membrane offers a new strategy to develop fit-for purpose membranes for resource recovery and water separation.