Ascorbic-acid-assisted growth of high quality M@ZnO: a growth mechanism and kinetics study

Ternary heterostructure-driven photoinduced electron-hole separation enhanced oxidative stress for triple-negative breast cancer therapy

Zinc oxide nanoparticles (ZnO NPs) stand as among the most significant metal oxide nanoparticles in trigger the formation of reactive oxygen species (ROS) and induce apoptosis. Nevertheless, the utilization of ZnO NPs has been limited by the shallowness of short-wavelength light and the constrained production of ROS. To overcome these limitations, a strategy involves achieving a red shift towards the near-infrared (NIR) light spectrum, promoting the separation and restraining the recombination of electron-hole (e--h+) pairs. Herein, the hybrid plasmonic system Au@ZnO (AZ) with graphene quantum dots (GQDs) doping (AZG) nano heterostructures is rationally designed for optimal NIR-driven cancer treatment. Significantly, a multifold increase in ROS generation can be achieved through the following creative initiatives: (i) plasmonic Au nanorods expands the photocatalytic capabilities of AZG into the NIR domain, offering a foundation for NIR-induced ROS generation for clinical utilization; (ii) elaborate design of mesoporous core-shell AZ structures facilitates the redistribution of electron-hole pairs; (iii) the incorporation GQDs in mesoporous structure could efficiently restrain the recombination of the e--h+ pairs; (iv) Modification of hyaluronic acid (HA) can enhance CD44 receptor mediated targeted triple-negative breast cancer (TNBC). In addition, the introduced Au NRs present as catalysts for enhancing photothermal therapy (PTT), effectively inducing apoptosis in tumor cells. The resulting HA-modified AZG (AZGH) exhibits efficient hot electron injection and e--h+ separation, affording unparalleled convenience for ROS production and enabling NIR-induced PDT for the cancer treanment. As a result, our well-designed mesoporous core-shell AZGH hybrid as photosensitizers can exhibit excellent PDT efficacy.

Triphenylphosphonium-Functionalized Gold Nanorod/Zinc Oxide Core-Shell Nanocomposites for Mitochondrial-Targeted Phototherapy

Phototherapies, such as photothermal therapy (PTT) and photodynamic therapy (PDT), combined with novel all-in-one light-responsive nanocomposites have recently emerged as new therapeutic modalities for the treatment of cancer. Herein, we developed novel all-in-one triphenylphosphonium-functionalized gold nanorod/zinc oxide core-shell nanocomposites (CTPP-GNR@ZnO) for mitochondrial-targeted PTT/PDT owing to their good biocompatibility, tunable and high optical absorption, photothermal conversion efficiency, highest reactive oxygen species (ROS) generation, and high mitochondrial-targeting capability. Under laser irradiation of 780 nm, the CTPP-GNR@ZnO core-shell nanocomposites effectively produced heat in addition to generating ROS to induce cell death, implying a synergistic effect of mild PTT and PDT in combating cancer. Notably, the in vitro PTT/PDT effect of CTPP-GNR@ZnO core-shell nanocomposites exhibited effective cell ablation (95%) and induced significant intracellular ROS after the 780 nm laser irradiation for 50 min, indicating that CTPP in CTPP-GNR@ZnO core-shell nanocomposites can specifically target the mitochondria of CT-26 cells, as well as generate heat and ROS to completely kill cancer cells. Overall, this light-responsive nanocomposite-based phototherapy provides a new approach for cancer synergistic therapy.

Recent Advances, Challenges, and Future Perspectives of ZnO Nanostructure Materials Towards Energy Applications

In this approach, zinc oxide (ZnO) is a multipurpose substance with remarkable characteristics such as high sensitivity, a large specific area, non-toxicity, excellent compatibility, and a high isoelectric point, which make it attractive for discussion with some limitations. It is the most favorable possible option for the collection of nanostructures in terms of structure and their characteristics. The development of numerous ZnO nanostructure-based electrochemical sensors and biosensors used in health diagnosis, pharmaceutical evaluation, food hygiene, and contamination of the environment monitoring is described, as well as the production of ZnO nanostructures. Nanostructured ZnO has good chemical and temperature durability as an n-type semiconducting material, making it useful in a wide range of uses, from luminous materials to supercapacitors, batteries, solar cells, photocatalysis, biosensors, medicinal devices, and more. When compared to the bulk materials, the nanosized materials have both a higher rate of disintegration and a higher solubility. Furthermore, ZnO nanoparticles are regarded as top contenders for electrochemical sensors due to their strong electrochemical behaviors and electron transmission characteristics. The impact of many factors, including selectivity, sensitivity, detection limit, strength, and structures, arrangements, and their respective functioning processes, has been investigated. This study concentrated a substantial amount of its attention on the recent advancements that have been made in ZnO-based nanoparticles, composites, and modified materials for use in the application areas of energy storage and conversion devices as well as biological applications. Supercapacitors, Li-ion batteries, dye-sensitized solar cells, photocatalysis, biosensors, medicinal, and biological systems have been studied. ZnO-based materials are constantly analyzed for their advantages in energy and life science applications.

Integrated Surface Modulation of Ultrahigh Ni Cathode Materials for Improved Battery Performance

Ni-rich layered cathodes with ultrahigh nickel content (≥90%), for example LiNi_0.9 Co_0.1 O₂ (NC0.9), are promising for next-generation high-energy Li-ion batteries (LIBs), but face stability issues related to structural degradation and side reactions during the electrochemical process. Here, surface modulation is demonstrated by integrating a Li⁺ -conductive nanocoating and gradient lattice doping to stabilize the active cathode efficiently for extended cycles. Briefly, a wet-chemistry process is developed to deposit uniform ZrO(OH)₂ nanoshells around Ni_0.905 Co_0.095 (OH)₂ (NC0.9-OH) hydroxide precursors, followed by high temperature lithiation to create reinforced products featuring Zr doping in the crust lattice decorated with Li₂ ZrO₃ nanoparticles on the surface. It is identified that the Zr⁴⁺ infiltration reconstructed the surface lattice into favorable characters such as Li⁺ deficiency and Ni³⁺ reduction, which are effective to combat side reactions and suppress phase degradation and crack formation. This surface control is able to achieve an optimized balance between surface stabilization and charge transfer, resulting in an extraordinary capacity retention of 96.6% after 100 cycles at 1 C and an excellent rate capability of 148.8 mA h g^-1 at 10 C. This study highlights the critical importance of integrated surface modulation for high stability of cathode materials in next-generation LIBs.

Upconversion boosting pollutants degradation efficiency in wide-spectrum responsive photocatalysts

Recently, the composite photocatalysts coupled with upconversion materials have received widespread attention due to higher utilization efficiency of solar energy in a wide-spectrum range. Novel heterojunction photocatalysts of CoWO₄@NaYF₄:Yb³⁺,Er³⁺ were designed and developed herein. The structural characterization, morphology and elemental composition analysis demonstrated that heterojunctions between CoWO₄ and NaYF₄:Yb³⁺,Er³⁺ were indeed formed in the composite photocatalysts. Moreover, CoWO₄@NaYF₄:Yb³⁺,Er³⁺ heterojunction photocatalysts exhibited higher pollutants degradation efficiency. Especially, a great enhancement of +87% on the photocatalytic activity was achieved in the heterojunction photocatalyst of 60CoWO₄-NaYF₄:Yb³⁺,Er³⁺ compared with pure CoWO₄. The dominant radicals generated from the heterojunction photocatalysts were confirmed as the photo-generated holes (h⁺) and hydroxyl radicals (⋅OH) through the radical species trapping experiments and fluorescence detection, which is fully in line with the expected band structure characteristics of CoWO₄. Eventually, an underlying mechanism was proposed that the enhanced photocatalytic activity should be attributed to the wide-spectrum responsive features of CoWO₄@NaYF₄:Yb³⁺,Er³⁺ heterojunction photocatalysts. Within the heterostructures, CoWO₄ photocatalyst can absorb both the UV-Vis light due to its narrow bandgap and the Near-Infrared energy through the upconversion NaYF₄:Yb³⁺,Er³⁺, thereby utilizing solar energy more efficiently in a wide-spectrum range for photocatalytic reactions.

Synthesis of Fe3O4@CdS@CQDs ternary core-shell heterostructures as a magnetically recoverable photocatalyst for selective alcohol oxidation coupled with H2O2 production

Photocatalytic aerobic oxidation of aromatic alcohols to corresponding aldehydes coupled with producing hydrogen peroxide (H₂O₂) represents one of the most efficient strategies for converting solar energy into chemical energy. In this work, a magnetically recoverable photocatalyst of Fe₃O₄@CdS@CQDs ternary core-shell heterostructures is elaborately fabricated through the hydrothermal growth of CdS on Fe₃O₄ nanospheres with in-situ incorporation of carbon quantum dots (CQDs) and used for selective alcohol oxidation coupled with H₂O₂ production. The Fe₃O₄@CdS@CQDs photocatalyst possess distinct advantages of full solar spectral absorption, efficient charge separation, and high stability. The Fe₃O₄-nanosphere cores not only endow photocatalyst with the characteristics of magnetic recovery but also form Fe₃O₄@CdS Z-scheme heterojunction to prevent CdS from photocorrosion. The in-situ modified CQDs act as charge mediators to accelerate the photogenerated electron-hole separation and afford active sites to facilitate H₂O₂ production. As a result, the Fe₃O₄@CdS@CQDs photocatalyst exhibits excellent performance in selectively converting benzyl alcohol to benzaldehyde accompanied with H₂O₂ production. The generation rates of benzaldehyde and H₂O₂ reach up to 57.22 and 27.06 mmol·g_CdS^-1·h^-1, respectively. This work highlights a rational construction of magnetic heterostructure photocatalyst and its application in the photo-redox coupling reactions.

Omnidirectional Hydrogen Generation Based on a Flexible Black Gold Nanotube Array

Solar-driven hydrogen generation is emerging as an economical and sustainable means of producing renewable energy. However, current photocatalysts for hydrogen generation are mostly powder-based or rigid-substrate-supported, which suffer from limitations, such as difficulties in catalyst regeneration or poor omnidirectional light-harvesting. Here, we report a two-dimensional (2D) flexible photocatalyst based on elastomer-supported black gold nanotube (GNT) arrays with conformal CdS coating and Pt decoration. The highly porous GNT arrays display a strong light-trapping effect, leading to near-complete absorption over almost the entire range of the solar spectrum. In addition, they offer high surface-to-volume ratios promoting efficient photocatalytic reactions. These structural features result in high H₂ generation efficiencies. Importantly, our elastomer-supported photocatalyst displays comparable photocatalytic activity even when being mechanically deformed, including bending, stretching, and twisting. We further designed a three-dimensional (3D) tree-like flexible photocatalytic system to mimic Nature's photosynthesis, which demonstrated omnidirectional H₂ generation. We believe our strategy represents a promising route in designing next-generation solar-to-fuel systems that rival natural plants.

Precise surface control of cathode materials for stable lithium-ion batteries

The increasing demand for high-energy Li-ion batteries (LIBs) continues to push the development of electrode materials, particularly cathode materials, towards their capacity limits. Despite the enormous success, the stability and reliability of LIBs are becoming a serious concern due to the much-aggravated side reactions between electrode materials and organic electrolytes. How to stabilize the cathode/electrolyte interface is therefore an imperative and urgent task drawing considerable attention from both academia and industry. An active treatment on the surface of cathode materials, usually by introducing an inert protection layer, to diminish their side reaction with electrolytes turns out to be a reasonable and effective strategy. This Feature Article firstly outlines our synthesis efforts for the construction of a uniform surface nanocoating on various cathode materials. Different wet chemical routes have been designed to facilitate the control of growth kinetics of targeted coating species so that a precise surface coating could be achieved with nanometer accuracy. Furthermore, we showed the possibility to transform the outer coating layer into a surface doping effect through surface solid reaction at high temperature. A detailed discussion on the structure-performance relationship of these surface-controlled cathode materials is introduced to probe the stabilization mechanism. Finally, perspectives on the development tendency of high-energy cathodes for stable LIBs are provided.

Gold Nanorods: The Most Versatile Plasmonic Nanoparticles

Gold nanorods (NRs), pseudo-one-dimensional rod-shaped nanoparticles (NPs), have become one of the burgeoning materials in the recent years due to their anisotropic shape and adjustable plasmonic properties. With the continuous improvement in synthetic methods, a variety of materials have been attached around Au NRs to achieve unexpected or improved plasmonic properties and explore state-of-the-art technologies. In this review, we comprehensively summarize the latest progress on Au NRs, the most versatile anisotropic plasmonic NPs. We present a representative overview of the advances in the synthetic strategies and outline an extensive catalogue of Au-NR-based heterostructures with tailored architectures and special functionalities. The bottom-up assembly of Au NRs into preprogrammed metastructures is then discussed, as well as the design principles. We also provide a systematic elucidation of the different plasmonic properties associated with the Au-NR-based structures, followed by a discussion of the promising applications of Au NRs in various fields. We finally discuss the future research directions and challenges of Au NRs.

Seagrass-inspired design of soft photocatalytic sheets based on hydrogel-integrated free-standing 2D nanoassemblies of multifunctional nanohexagons

Natural leaves are virtually two-dimensional (2D) flexible photocatalytic system. In particular, seagrass can efficiently harvest low-intensity sunlight to drive photochemical reactions continuously in an aqueous solution. To mimic this process, we present a novel 2D hydrogel-integrated photocatalytic sheet based on free-standing nanoassemblies of multifunctional nanohexagons (mNHs). The mNHs building blocks is made of plasmonic gold nanohexagons (NHs) decorated with Pd nanoparticles in the corners and CdS nanoparticles throughout their exposed surfaces. The mNHs can self-assemble into free-standing 2D nanoassemblies and be integrated with thin hydrogel films, which can catalyze chemical reactions under visible light illumination. Hydrogels are translucent, porous, and soft, allowing for continuous photochemical conversion in an aqueous environment. Using methylene blue (MB) as a model system, we demonstrate a soft seagrass-like photodegradation design, which offers high efficiency, continuous operation without the need of catalyst regeneration, and omnidirectional light-harvesting capability under low-intensity sunlight irradiation, defying their rigid substrate-supported random aggregates and solution-based discrete counterparts.

Donor-Acceptor Compensated ZnO Semiconductor for Photoelectrochemical Biosensors

Hindering the recombination of a photogenerated carrier is a crucial method to enhance the photoelectrochemical performance of ZnO due to its high exciton binding energy. Herein, the intramolecular donor-acceptor compensated semiconductor ZnO (I-D/A ZnO), introducing C dopants and oxygen vacancies, was prepared with the assistance of ascorbic acid (AA). According to the DFT calculations, the asymmetry DOS could lead to the longer carrier lifetime and the smaller electron transfer resistance. Then, the photoelectrochemical biosensor toward glucose was regarded as a model to discuss the application of ZnO in biosensors. As a result, the biosensor based on I-D/A ZnO showed good performance with high sensitivity, low limit of detection, and fine anti-interference, meaning that I-D/A ZnO is a promising semiconductor for photoelectrochemical biosensors.

Tunable thickness of mesoporous ZnO-coated metal nanoparticles for enhanced visible-light driven photoelectrochemical water splitting

The insufficient utilization of sunlight of ZnO, due to its broad band gap, results in low efficiency for photocatalytic hydrogen production. In this work, plasmonic noble metal nanoparticles (NPs) with different shapes (spheres and rods) were combined with mesoporous ZnO forming core-shell nanostructure to enhance the photocatalytic efficiency of ZnO in visible-light region. The photoelectrochemical water splitting activities of the metal@ZnO core-shell nanocomposites (NCs) were investigated. The photocurrent response of metal@ZnO NCs was found higher than pure ZnO or the mixture of metal NPs and ZnO ascribed to the effective charge transfer mechanism. It was also found that the photocurrent of metal@ZnO NCs was related to the thickness of ZnO and there was optimized shell for each kind of metal cores. Moreover, the introduction of Ag shell can get a higher photoelectrocatalytic efficiency compared to pure Au NPs core due to lower Schottky barrier between Ag and ZnO and wider extinction range in the visible light of Au@Ag NPs.

Tunable Size Dependence of Quantum Plasmon of Charged Gold Nanoparticles

The quantum behavior of surface plasmons has received extensive attention, benefiting from the development of exquisite nanotechnology and the diverse applications. Blueshift, redshift, and nonshift of localized surface plasmon resonances (LSPRs) have all been reported as the particle size decreases and enters the quantum size regime, but the underlying physical mechanism to induce these controversial size dependences is not clear. Herein, we propose an improved semiclassical model for modifying the dielectric function of metal nanospheres by combining the intrinsic quantized electron transitions and surface electron injection or extraction to investigate the plasmon shift and LSPR size dependence of the charged Au nanoparticles. We experimentally observe that the nonmonotonic blueshift of LSPRs with size for Au nanoparticles is turned into an approximately monotonic blueshift by increasing the electron donor concentration in the reduction solution, and it can also be transformed to an approximately monotonic redshift after surface passivation by ligand molecules. Moreover, we demonstrate controlled blueshift and redshift for the electron and hole plasmons in Cu_{2-x}S@Au core-shell nanoparticles by injecting electrons. The experimental observations and the theoretical calculations clarify the controversial size dependences of LSPR reported in the literature, reveal the critical role of surface electron injection or extraction in the transformation between the different size dependences of LSPRs, and are helpful for understanding the nature of surface plasmons in the quantum size regime.

Bistratal Au@Bi2S3 nanobones for excellent NIR-triggered/multimodal imaging-guided synergistic therapy for liver cancer

To fabricate a highly biocompatible nanoplatform enabling synergistic therapy and real-time imaging, novel Au@Bi₂S₃ core shell nanobones (NBs) (Au@Bi₂S₃ NBs) with Au nanorods as cores were synthesized. The combination of Au nanorods with Bi₂S₃ film made the Au@Bi₂S₃ NBs exhibit ultrahigh photothermal (PT) conversion efficiency, remarkable photoacoustic (PA) imaging and high computed tomography (CT) performance; these Au@Bi₂S₃ NBs thus are a promising nanotheranostic agent for PT/PA/CT imaging. Subsequently, poly(N-vinylpyrrolidone)-modified Au@Bi₂S₃ NBs (Au@Bi₂S₃-PVP NBs) were successfully loaded with the anticancer drug doxorubicin (DOX), and a satisfactory pH sensitive release profile was achieved, thus revealing the great potential of Au@Bi₂S₃-PVP NBs in chemotherapy as a drug carrier to deliver DOX into cancer cells. Both in vitro and in vivo investigations demonstrated that the Au@Bi₂S₃-PVP NBs possessed multiple desired features for cancer therapy, including extremely low toxicity, good biocompatibility, high drug loading ability, precise tumor targeting and effective accumulation. Highly efficient ablation of the human liver cancer cell HepG2 was achieved through Au@Bi₂S₃-PVP NB-mediated photothermal therapy (PTT). As both a contrast enhancement probe and therapeutic agent, Au@Bi₂S₃-PVP NBs provided outstanding NIR-triggered multi-modal PT/PA/CT imaging-guided PTT and effectively inhibited the growth of HepG2 liver cancer cells via synergistic chemo/PT therapy.

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Novel Au@Bi₂S₃ core shell NBs were synthesized with ultrahigh photothermal conversion efficiency (η=68.1%).

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The Au@Bi₂S₃-PVP NBs can serve as a multimodal imaging agent for PT/PA/CT imaging.

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The Au@Bi₂S₃-PVP NBs can act as nanocarrier for anticancer drug DOX in a pH sensitive DOX release profile.

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This work reports outstanding NIR-triggered trimodal PT/PA/CT imaging-guided chemo/PT synergistic therapy of liver cancer.

Thermal pyrolysis of Si@ZIF-67 into Si@N-doped CNTs towards highly stable lithium storage

Silicon is attracting considerable attention as an active anode material for advanced lithium-ion batteries due to its ultrahigh theoretical capacity. However, the reversible utilization of silicon-based anode materials is still hindered by the rapid capacity decay, as a consequence of the huge volume change of silicon during cycling. Herein, we use a Co-zeolitic imidazole framework (ZIF-67) to prepare silicon-wrapped nitrogen-doped carbon nanotubes (Si@N-doped CNTs) by controllable thermal pyrolysis. The as-prepared nanocomposites can effectively prevent pulverization and accommodate volume fluctuations of silicon during cycling. It can deliver a highly reversible capacity of 1100 mAh g^-1 even after 750 cycles at a current density of 1000 mA g^-1. As confirmed by an in situ transmission electron microscopy experiment, the remarkable electrochemical performance of Si@N-doped CNTs is attributed to the high electronic conductivity and flexibility of cross-linked N-doped CNTs network as a cushion to mitigate the mechanical stress and volume expansion. Furthermore, a full cell consisting of Si@N-doped CNTs anode and LiFePO₄ cathode delivers a high reversible capacity of 1264 mAh g^-1 and exhibits good cycling stability (>85% capacity retention) over 140 cycles at 1/4 C (1 C = 4000 mA g^-1) rate.

Recent progress and perspectives of gas sensors based on vertically oriented ZnO nanomaterials

Vertically oriented zinc oxide (ZnO) nanomaterials, such as nanorods (NRs), nanowires (NWs), nanotubes (NTs), nanoneedles (NNs), and nanosheets (NSs), are highly ordered architectures that provide remarkable properties for sensors. Furthermore, these nanostructures have fascinating features, including high surface-area-to-volume ratios, high charge carrier concentrations, and many surface-active sites. These features make vertically oriented ZnO nanomaterials exciting candidates for gas sensor fabrication. The development of efficient methods for the production of vertically oriented nanomaterial electrode surfaces has resulted in improved stability, high reproducibility, and gas sensing performance. Moving beyond conventional fabrication processes that include binders and nanomaterial deposition steps has been crucial, as the materials from these processes suffer from poor stability, low reproducibility, and marginal sensing performance. In this feature article, we comprehensively describe vertically oriented ZnO nanomaterials for gas sensing applications. The uses of such nanomaterials for gas sensor fabrication are discussed in the context of ease of growth, stability on an electrode surface, growth reproducibility, and enhancements in device efficiency as a result of their unique and advantageous features. In addition, we summarize applications of gas sensors for a variety of toxic and volatile organic compound (VOC) gases, and we discuss future directions of the vertically oriented ZnO nanomaterials.

Construction of novel hybrid PdO–ZnO p–n heterojunction nanostructures as a high-response sensor for acetaldehyde gas

A facile and unique approach to design PdO@ZnO p–n heterojunction nanostructures (NSs) as a highly sensitive and selective acetaldehyde gas sensor.

Light-Responsive Biodegradable Nanorattles for Cancer Theranostics

Cancer nanotheranostics, integrating both diagnostic and therapeutic functions into nanoscale agents, are advanced solutions for cancer management. Herein, a light-responsive biodegradable nanorattle-based perfluoropentane-(PFP)-filled mesoporous-silica-film-coated gold nanorod (GNR@SiO₂ -PFP) is strategically designed and prepared for enhanced ultrasound (US)/photoacoustic (PA) dual-modality imaging guided photothermal therapy of melanoma. The as-prepared nanorattles are composed of a thin mesoporous silica film as the shell, which endows the nanoplatform with flexible morphology and excellent biodegradability, as well as large cavity for PFP filling. Upon 808 nm laser irradiation, the loaded PFP will undergo a liquid-gas phase transition due to the heat generation from GNRs, thus generating nanobubbles followed by the coalescence into microbubbles. The conversion of nanobubbles to microbubbles can improve the intratumoral permeation and retention in nonmicrovascular tissue, as well as enhance the tumor-targeted US imaging signals. This nanotheranostic platform exhibits excellent biocompatibility and biodegradability, distinct gas bubbling phenomenon, good US/PA imaging contrast, and remarkable photothermal efficiency. The results demonstrate that the GNR@SiO₂ -PFP nanorattles hold great potential for cancer nanotheranostics.

Gadolinium oxysulfide-coated gold nanorods with improved stability and dual-modal magnetic resonance/photoacoustic imaging contrast enhancement for cancer theranostics

Gold nanorods (GNRs) are emerging as a promising nanoplatform for cancer theranostics because of their unique optical properties. However, they still suffer from many limitations, such as high cytotoxicity, low thermodynamic and biological stability, and a tedious process for integrating other imaging modalities, for further practical biomedical applications. In this work, a strategy by one-step coating of Gd₂O₂S around GNRs is reported to address these limitations of GNRs. After the coating of the Gd₂O₂S shell, the as-fabricated Gd₂O₂S coated GNRs (GNRs@Gd₂O₂S) show enhanced biocompatibility and photostability, and tunable localized surface plasmon resonance. The strong absorption in the near-infrared region renders GNRs@Gd₂O₂S outstanding photoacoustic imaging and photothermal therapy capabilities. Moreover, owing to the T₁ shortening ability of Gd₂O₂S, the GNRs@Gd₂O₂S also show an excellent T₁ MRI contrast performance. The GNRs@Gd₂O₂S thus can serve as a versatile nanoplatform for cancer theranostics combining dual-modal imaging and photothermal therapy.

Complete Au@ZnO core-shell nanoparticles with enhanced plasmonic absorption enabling significantly improved photocatalysis

Nanostructured ZnO exhibits high chemical stability and unique optical properties, representing a promising candidate among photocatalysts in the field of environmental remediation and solar energy conversion. However, ZnO only absorbs the UV light, which accounts for less than 5% of total solar irradiation, significantly limiting its applications. In this article, we report a facile and efficient approach to overcome the poor wettability between ZnO and Au by carefully modulating the surface charge density on Au nanoparticles (NPs), enabling rapid synthesis of Au@ZnO core-shell NPs at room temperature. The resulting Au@ZnO core-shell NPs exhibit a significantly enhanced plasmonic absorption in the visible range due to the Au NP cores. They also show a significantly improved photocatalytic performance in comparison with their single-component counterparts, i.e., the Au NPs and ZnO NPs. Moreover, the high catalytic activity of the as-synthesized Au@ZnO core-shell NPs can be maintained even after many cycles of photocatalytic reaction. Our results shed light on the fact that the Au@ZnO core-shell NPs represent a promising class of candidates for applications in plasmonics, surface-enhanced spectroscopy, light harvest devices, solar energy conversion, and degradation of organic pollutants.

Au@ZnO core–shell nanostructures with plasmon-induced visible-light photocatalytic and photoelectrochemical properties

Au@ZnO core–shell nanostructures exhibit enhanced photocatalysis under both simulated sunlight and monochromatic LED light due to the synergistic effect between the plasmonic Au-nanosphere cores and the semiconducting ZnO shells.

Stable and magnetically reusable nanoporous magnetite micro/nanospheres for rapid extraction of carcinogenic contaminants from water

Schematic shows the overall experimental details of hydrothermal process and formation of porous structures with magnetic separability test.

Facile synthesis of flower-shaped Au/GdVO4:Eu core/shell nanoparticles by using citrate as stabilizer and complexing agent

The synthesis of metal/rare-earth core/shell hetero-nanostructures through directly coating rare-earth compound onto the surface of Au nanocrystals.

Facile Approach to Synthesize Au@ZnO Core-Shell Nanoparticles and Their Application for Highly Sensitive and Selective Gas Sensors

We successfully prepared Au@ZnO core-shell nanoparticles (CSNPs) by a facile low-temperature solution route and studied its gas-sensing properties. The obtained Au@ZnO CSNPs were carefully characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, and UV-visible spectroscopy. Mostly spherical-shaped Au@ZnO CSNPs were formed by 10-15 nm Au NPs in the center and by 40-45 nm smooth ZnO shell outside. After the heat-treatment process at 500 °C, the crystallinity of ZnO shell was increased without any significant change in morphology of Au@ZnO CSNPs. The gas-sensing test of Au@ZnO CSNPs was examined at 300 °C for various gases including H2 and compared with pure ZnO NPs. The sensor Au@ZnO CSNPs showed the high sensitivity and selectivity to H2 at 300 °C. The response values of Au@ZnO CSNPs and pure ZnO NPs sensors to 100 ppm of H2 at 300 °C were 103.9 and 12.7, respectively. The improved response of Au@ZnO CSNPs was related to the electronic sensitization of Au NPs due to Schottky barrier formation. The high selectivity of Au@ZnO CSNPs sensor toward H2 gas might be due to the chemical as well as catalytic effect of Au NPs.

Noble metal@metal oxide semiconductor core@shell nano-architectures as a new platform for gas sensor applications

This feature article focuses on recent research progress in noble metal@metal oxides core@shell NPs for gas sensor applications.