Rational Design and Development of Lanthanide-Doped NaYF4@CdS-Au-RGO as Quaternary Plasmonic Photocatalysts for Harnessing Visible-Near-Infrared Broadband Spectrum

Luminescence enhancement through co-sensitization in lanthanide composites for efficient photocatalysis

Lanthanide-doped nanocrystals that convert near-infrared (NIR) irradiation into shorter wavelength emission (ultraviolet-C) offer many exciting opportunities for biomedicine, bioimaging, and environmental catalysis. However, developing lanthanide-doped nanocrystals with high UVC brightness for efficient photocatalysis is a formidable challenge due to the complexity of the multiphoton process. Here, we report a series of heterogeneous core-multishell structures based on a co-sensitization strategy with multi-band enhanced emission profiles under 980 nm excitation. Interestingly, the multiphoton processes involving two to six-photon upconversion are highly promoted via a co-sensitization strategy. More importantly, through growth layers of TiO2 and CdS photocatalysts, these lanthanide nanocomposites with efficient multi-upconverted emission show efficient photocatalytic activity. This study provides a new perspective for mechanistic understanding of multiphoton processes in heterostructures and also offers exciting opportunities for highly efficient photocatalytic applications.

A ternary nucleotide-lanthanide coordination nanoprobe for ratiometric fluorescence detection of ciprofloxacin

Ciprofloxacin (CIP) is a widely used broad-spectrum antibiotic and has been associated with various side effects, making its accurate detection crucial for patient safety, drug quality compliance, and environmental and food safety. This study presents the development of a ternary nucleotide-lanthanide coordination nanoprobe, GMP-Tb-BDC (GMP: guanosine 5'-monophosphate, BDC: 2-amino-1,4-benzenedicarboxylic acid), for the sensitive and ratiometric detection of CIP. The GMP-Tb-BDC nanoprobe was constructed by incorporating the blue-emissive ligand BDC into the Tb/GMP coordination polymers. Upon the addition of CIP, the fluorescence of terbium ion (Tb3+ ) was significantly enhanced due to the coordination and fluorescence sensitization properties of CIP, while the emission of the BDC ligand remained unchanged. The nanoprobe demonstrated good linearity in the concentration range of 0-10 μM CIP. By leveraging mobile phone software to analyze the color signals, rapid on-site analysis of CIP was achieved. Furthermore, the nanoprobe exhibited accurate analysis of CIP in actual drug and milk samples. This study showcases the potential of the GMP-Tb-BDC nanoprobe for practical applications in CIP detection.

UV-to-NIR Harvesting Conjugated Porous Polymer Nanocomposite: Upconversion and Plasmon Expedited Thioether Photooxidation

Photocatalysts capable of harvesting a broad range of the solar spectrum are essential for sustainable chemical transformations and environmental remediation. Herein, we have integrated NIR-absorbing upconversion nanoparticles (UCNP) with UV-Vis absorbing conjugated porous organic polymer (POP) through the in situ multicomponent C-C coupling to fabricate a UC-POP nanocomposite. The light-harvesting ability of UC-POP is further augmented by loading plasmonic gold nanoparticles (AuNP) into UC-POP. A three-times enhancement in the upconversion luminescence is observed upon the incorporation of AuNP in UC-POP, subsequently boosting the photocatalytic activity of UC-POP-Au. The spectroscopic and photoelectrochemical investigations infer the enhanced photocatalytic oxidation of thioethers, including mustard gas simulant by UC-POP-Au compared to POP and UC-POP due to the facile electron-hole pair generation, suppressed exciton recombination, and efficient charge carrier migration. Thus, the unique design strategy of combining plasmonic and upconversion nanoparticles with a conjugated porous organic polymer opens up new vistas towards artificial light harvesting.

In Situ Construction of Near-Infrared Response Hybrid Up-Conversion Photocatalyst for Degrading Organic Dyes and Antibiotics

Unique nonlinear optical properties for converting low-energy incident light into high-energy radiation enable up-conversion materials to be employed in photocatalytic systems. An efficient near-infrared (NIR) response photocatalyst was successfully fabricated through a facile two-step method to load BiOBr on the Nd3+, Er3+@NaYF4 (NE@NYF) up-conversion material. The NE@NYF can transform NIR into visible and UV light and promote charge-energy transfer in the semiconductor. Consequently, the as-obtained photocatalysts exhibit excellent photodegradation performance for rhodamine B dye (RhB) and tetracycline (TC) organic pollutants. About 98.9% of the RhB was decomposed within 60 min with the 20% NE@NYF-B sample, outperforming the pristine BiOBr (61.9%). In addition, the 20% NE@NYF-B composite could decompose approximately 72.7% of the organic carbon during a 10 h reaction, which was almost two-fold more than that of BiOBr. Meanwhile, a possible charge transfer mechanism is proposed based on the recombination of electron-hole pairs and reactive oxygen species. This work provides a rational hybrid structure photocatalyst for improving photocatalytic performance in the broadband spectrum and provides a new strategy for NIR light utilization.

Twisty C-TiO2 /PCN S-Scheme Heterojunction with Enhanced n→π * Electronic Excitation for Promoted Piezo-Photocatalytic Effect

Herein, a twisty C-TiO₂ /PCN (CNT) Step-scheme (S-scheme) heterojunction is fabricated and applied to degrade ciprofloxacin (CIP) with the assistance of ultrasonic vibration and visible light irradiation. The nitrogen-rich twisty polymeric carbon nitride (PCN) can not only induce a non-centrosymmetric structure with enhanced polarity for a better piezoelectric effect but also provide abundant lone pair electrons to promote n→π* transition during photocatalysis. Its hybridization with C-TiO₂ particles can construct S-scheme heterojunction in CNT. During the piezo-photocatalysis, the strain-induced polarization electric field in the heterojunction can regulate the electron migration between the two components, resulting in a more effective CIP degradation. With the synergistic effect of ultrasonic vibration and visible light irradiation, the reaction rate constant of CIP degradation by CNT increases to 0.0517 min^-1 , which is 1.86 times that of photocatalysis and 6.46 times that of ultrasound. This system exhibits a stable CIP decomposition efficiency under the interference of various environmental factors. In addition, the in-depth investigation found that three pathways and 12 major intermediates with reduced toxicity are produced after the reaction. Hopefully, the construction of this twisty CNT S-scheme heterojunction with enhanced piezo-photocatalytic effect offers inspiration for the design of environmentally functional materials.

Boosted visible-light-driven degradation over stable ternary heterojunction as a plasmonic photocatalyst: Mechanism exploration, pathway and toxicity evaluation

The incorporation of plasmonic metals into semiconductors forming heterojunction photocatalysts is a promising route to enhance the photocatalytic performance in visible light. In this work, we reported the visible-light-driven one-dimensional (1D) nanostick silver/silver sulfide (Ag/Ag₂S) photocatalyst combining with two-dimensional (2D) nanosheet reduced graphene oxide intersected by hollow structure (h-RGO) was prepared via a feasible approach at room temperature. The density of Ag depositing on the surface of Ag₂S was easily tuned by the concentration of sodium borohydride and the silicon dioxide nanospheres were employed as templates in the preparation of h-RGO by the layer-by-layer (LBL) assembly. The ternary plasmonic Ag/Ag₂S/h-RGO photocatalysts exhibited better photocatalytic performance for degradation of naphthalene (95.95%) and 1-naphthol (98.65%) under visible light than the pure Ag₂S, composite Ag/Ag₂S and composite Ag/Ag₂S/RGO. Localized surface plasmon resonance of Ag, heterojunction formed between Ag/Ag₂S and RGO and the unique characteristics of h-RGO, which included higher specific surface areas, more efficient reflections of light and more active sites than RGO for boosting separation efficiency of charge carriers, were all responsible for such enhancement. By combining the characterization results with various computations, the mechanism, potential degradation pathways and the toxicity of the generated intermediates for photodegradation were examined. In addition to offering profound insight into the expansion of effective plasmonic photocatalysts with novel structures, the current study is beneficial to ease the environmental crisis to a certain extent.

Recent advances in structural engineering of photocatalysts for environmental remediation

Photocatalysis appears to be an appealing approach for environmental remediation including pollutants degradation in water, air, and/or soil, due to the utilization of renewable and sustainable source of energy, i.e., solar energy. However, their broad applications remain lagging due to the challenges in pollutant degradation efficiency, large-scale catalyst production, and stability. In recent decades, massive efforts have been devoted to advance the photocatalysis technology for improved environmental remediation. In this review, the latest progress in this aspect is overviewed, particularly, the strategies for improved light sensitivity, charge separation, and hybrid approaches. We also emphasize the low efficiency and poor stability issues with the current photocatalytic systems. Finally, we provide future suggestions to further enhance the photocatalyst performance and lower its large-scale production cost. This review aims to provide valuable insights into the fundamental science and technical engineering of photocatalysis in environmental remediation.

MXene coupled graphitic carbon nitride nanosheets based plasmonic photocatalysts for removal of pharmaceutical pollutant

The continuous rise in the amount of industrial and pharmaceutical waste in water sources is an alarming concern. Effective strategies should be developed for the treatment of pharmaceutical industrial waste. Hence the alternative renewable source of energy, such as solar energy, should be utilized for a sustainable future. Herein, a series of Au plasmonic nanoparticle decorated ternary photocatalysts comprising graphitic carbon nitride and Ti₃C₂ MXene has been designed to degrade colourless pharmaceutical pollutants, cefixime under visible light irradiation. These photocatalysts were synthesized by varying the amount of Ti₃C₂ MXene, and their catalytic potential was explored. The optimized photocatalyst having 3 wt% Ti₃C₂ MXene achieved 64.69% removal of the pharmaceutical pollutant, cefixime within 105 min of exposure to visible light. The presence of the Au nanoparticles and MXene in the nanocomposite facilitates the excellent charge carrier separation and increased the number of active sites due to the formation of interfacial contact with graphitic carbon nitride nanosheets. Besides, the plasmonic effect of the Au nanoparticles improves the absorption of light causing enhanced photocatalytic performance of the nanocomposite. Based on the obtained results, a plausible mechanism has been formulated to understand the contribution of different components in photocatalytic activity. In addition, the optimized photocatalyst shows excellent activity and can be reused for up to three cycles without any significant loss in its photocatalytic performance. Overall, the current work provides deeper physical insight into the future development of MXene graphitic carbon nitride-based plasmonic ternary photocatalysts.

Synthesis of dye-sensitized TiO2/Ag doped nano-composites using UV photoreduction process for phenol degradation: A comparative study

This study investigates a comparison between the photocatalytic action of two nanocomposites (TiO₂ and TiO₂(Ag) doped) on the degradation of phenol from water. The nanocomposites were synthesized by the UV photo-reduction process to get a silver metal loading of 0.25, 0.5, 0.75, and 1% (w/w). In addition to this, Eriochrome Cyanine Red (ECR) and Eosin Yellow (EY) both anionic dyes were used for sensitization of Ag-doped TiO₂ photo-catalyst such as TiO₂(Ag)ECR and TiO₂(Ag)EY. The TiO₂(Ag-1.0)EY photo-catalyst indicated higher absorbance compared to the TiO₂(Ag-1.0)ECR in the 400-700 nm range (visible range). The degradation of phenol was tested by varying the pH, silver loading and catalyst dosage. The maximum degradation of phenol was 98% in 180 min at pH 7 in presence of 1% (w/w) silver loading with 0.5 gL^-1 dosage of photo-catalyst TiO₂(Ag-1.0)EY. At this condition, the reduction in the phenol concentration was noticed from 20 mg/L to 0.4 mg/L.

Bismuth quantum dots anchored one-dimensional CdS as plasmonic photocatalyst for pharmaceutical tetracycline hydrochloride pollutant degradation

Earth abundant metal based plasmonic photocatalysis is one of the most proficient approaches to degrade the emergent organic pollutants in contaminated water. Here, we report that using one-dimensional CdS/zero-dimensional Bi quantum dot (QD) heterostructures (1D/0D CdS/Bi HSs) were obtained via a simple solvothermal reaction. The results specified that the Bi QDs were grown onto CdS NRs through the reduction of Bi³⁺ ions. The Bi modified CdS HSs were employed as a photocatalyst for pharmaceutical pollutant tetracycline degradation and the optimized sample showed the maximum photocatalytic degradation activity of 90% under visible light radiation within 60 min, which is greater than the pure CdS (52%) under identical conditions. Based on the structural characterizations and degradation efficiency, the obtained CdS/Bi is a promising photocatalyst for the treatment of wastewater which contains emerging pollutants such as organic dyes and pharmaceutical antibiotics during the industrial processes. The boosted photocatalytic degradation efficiency is credited to the doped Bi³⁺ species; surface plasmon resonance effect that raised from metallic Bi QDs and proficient photoinduced charge carriers separation.

Encapsulation-Led Adsorption of Neutral Dyes and Complete Photodegradation of Cationic Dyes and Antipsychotic Drugs by Lanthanide-Based Macrocycles

Molecular architectures offering large cavities can accommodate guest molecules, while their compositional engineering allows tunability of the band gap to support photocatalysis using visible light. In this work, two lanthanide (Ln)-based macrocycles, synthesized using a cobalt-based metalloligand and offering large rectangular cavities, exhibited selective adsorption of neutral dyes over both anionic and cationic dyes. Both Ln macrocycles illustrated complete photodegradation of cationic dyes using visible light without the use of any oxidant. Both Ln macrocycles exhibited complete photodegradation of not only cationic dyes but also a few phenothiazine-based antipsychotic drugs. Photocatalysis involved the generation of reactive oxygen species (ROS), which was corroborated with the band gap of two Ln macrocycles. These results were supported by radical scavenger studies and the quantitative estimation of superoxide and hydroxyl radicals. Complete photodegradation of both dyes and drugs was confirmed by spectral studies, while the generation of CO₂ and N₂ gases was established by gas chromatography. Importantly, Ln macrocycles were able to distinguish between the neutral dyes that were quantitatively adsorbed and the cationic dyes/drugs that were completely photodegraded.

Enhancement of solar-driven photocatalytic activity of oxygen vacancy-rich Bi/BiOBr/Sr2LaF7:Yb3+,Er3+ composites through synergetic strategy of upconversion function and plasmonic effect

For better use of solar energy, the development of efficient broadband photocatalyst has attracted extraordinary attention. In this study, a ternary composite consisting of Sr₂LaF₇:Yb³⁺,Er³⁺ upconversion (UC) nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies (OVs, SLFBB) was designed and synthesized by multistep solvent-thermal method. Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr₂LaF₇:Yb³⁺,Er³⁺ composites (SFLB) are clarified. The Bi metal and OVs enhanced the light-harvesting capacity in the region of visible-near-infrared (Vis-NIR), and promoted the separation of electron-hole (e^-/h⁺) pairs. Furthermore, the surface plasmon resonance (SPR) effect of Bi metal can improve the energy transfer from Sr₂LaF₇:Yb³⁺,Er³⁺ to BiOBr via nonradiative energy transfer process, resulting in enhancing the light utilization from upconverting NIR into Vis light. Due to the synergistic effects of UC function, SPR and OVs, the SFLBB exhibited obviously enhanced photocatalytic ability for the degradation of BPA with a rate of 8.9 × 10^-3 min^-1, which is about 2.78 times higher than 3.2 × 10^-3 min^-1 of BiOBr (BOB) under UV-Vis-NIR light irradiation. This work provides a novel strategy for the project of high-efficiency Bismuth-based broadband photocatalysts, which is helpful to further understand the mechanism of enhanced photocatalysis by UC function and plasmonic effect.

Influence of oxygen vacancy defects on Aurivillius phase layered perovskite oxides of bismuth towards photocatalytic environmental remediation

The low light absorption and rapid recombination of photogenerated charge carriers are primary contributors to the low activity of various photocatalysts. Fabrication of oxygen vacancy defect-rich materials for improved photocatalytic activities has been attracting tremendous attention from researchers all over the world. In this work, we have compared the photocatalytic activities of oxygen vacancy-rich Bi₂MoO₆(BMO-O_V) and Bi₂WO₆(BWO-O_V) for the degradation of a model pharmaceutical pollutant, ciprofloxacin under visible light irradiation. The photocatalytic activity was increased from 47% to 77% and 40% to-67% for BMO-O_Vand BWO-O_V, respectively in comparison to pristine oxides. This enhancement can be ascribed to suppressed charge carrier recombination and increased surface active sites. In addition, scavenger studies have been done to explain the role of photoinduced charge carriers in the degradation mechanism. Moreover, oxygen vacancy-rich photocatalysts have remained stable even after three consecutive cycles, making them promising materials for practical applications. Overall, this work provides deeper insight into the design and development of oxygen vacancy-rich materials.

Wide-angle and broadband solar absorber made using highly efficient large-area fabrication strategy

High performance and cost-effective solar absorbers are crucial for various optical applications, such as solar collection and thermophotovoltaic devices. This study designs and experimentally demonstrates a wide-angle and broadband solar absorber. The proposed absorber is composed of tapered polyimide substrate and Al-Cr-SiO₂-Cr-SiO₂ thin-film based on the optical interference of the multilayer thin film and excited magnetic resonance of light-trapping structures. The composite process of the colloidal lithography method and magnetron sputtering is employed for efficient fabrication in a large area. The average absorbance is more than 93% from 300 nm to 2500 nm and shows an angular tolerance of up to 60°. The high efficiency and large-area fabrication capability demonstrated by the proposed solar absorber presents future application potential in flexible solar collection devices.

Enhanced photocatalytic activity of two dimensional ternary nanocomposites of ZnO-Bi2WO6-Ti3C2 MXene under natural sunlight irradiation

The design and development of advanced photocatalysts for water purification have attracted much attention from researchers in recent years. In this context, the two-dimensional (2D) semiconducting materials have shown excellent photocatalytic properties due to their merits of high surface area, confined longitudinal dimensions and excellent capability of efficient separation and transfer of photogenerated charge carriers. Herein, we report a novel 2D-2D-2D ternary photocatalyst ZnO-Bi₂WO₆-Ti₃C₂ by using a two-step electrostatic assembly route. The formation of the individual materials and nanocomposites was confirmed by x-ray diffraction and 2D morphology was ascertained by electron microscopy studies. The as-prepared photocatalysts were utilized for the degradation of a colorless pharmaceutical pollutant, ciprofloxacin (CFX) under natural sunlight irradiation. It was found that the optimized ternary photocatalyst showed a maximum degradation (∼77%) of CFX in 160 min. The mechanistic investigation showed that upon nanocomposite formation, the electrons flow from ZnO and Bi₂WO₆ to Ti₃C₂, implying that MXene plays an important role in the separation of photogenerated charges and thereby enhancing the photocatalytic activity. This work paves the way for the design and development of efficient photocatalysts for environmental remediation.

Recent Advances in Plasmonic Photocatalysis Based on TiO2 and Noble Metal Nanoparticles for Energy Conversion, Environmental Remediation, and Organic Synthesis

Plasmonic photocatalysis has emerged as a prominent and growing field. It enables the efficient use of sunlight as an abundant and renewable energy source to drive a myriad of chemical reactions. For instance, plasmonic photocatalysis in materials comprising TiO₂ and plasmonic nanoparticles (NPs) enables effective charge carrier separation and the tuning of optical response to longer wavelength regions (visible and near infrared). In fact, TiO₂ -based materials and plasmonic effects are at the forefront of heterogeneous photocatalysis, having applications in energy conversion, production of liquid fuels, wastewater treatment, nitrogen fixation, and organic synthesis. This review aims to comprehensively summarize the fundamentals and to provide the guidelines for future work in the field of TiO₂ -based plasmonic photocatalysis comprising the above-mentioned applications. The concepts and state-of-the-art description of important parameters including the formation of Schottky junctions, hot electron generation and transfer, near field electromagnetic enhancement, plasmon resonance energy transfer, scattering, and photothermal heating effects have been covered in this review. Synthetic approaches and the effect of various physicochemical parameters in plasmon-mediated TiO₂ -based materials on performances are discussed. It is envisioned that this review may inspire and provide insights into the rational development of the next generation of TiO₂ -based plasmonic photocatalysts with target performances and enhanced selectivities.

Autonomous magnetic microbots for environmental remediation developed by organic waste derived carbon dots

Biodegradable precursors for micro/nanobots development are key requirements for several sustainable applications. In this regard, we propose an innovative solution for water purification at minimum cost and efforts where organic waste is used for the treatment of organic pollutants. Herein, catalytic magnetic microbots were developed by functionalizing iron oxide nanoparticles with carbon dots (C-Dots), which were synthesized by using household waste such as potato peels as precursors. The speed of these autonomously propelling bots indeed is found very promising for large distance swimming even in viscous medium by using hydrogen peroxide as fuel. These microbots catalytically propel and degrade toxic polar as well as sparingly water-soluble industrial dyes without any external agitation. The degradation of dyes was confirmed by mass-spectra analysis. Furthermore, these microbots can efficiently degrade a mixture of dyes and reused without compromising its performance significantly. Additionally, rate constant (K) and activation energy (E_a) were also determined to establish the catalytic nature of the bots. The present microbots acted as nanozyme owing to its synergistic catalytic activity of Fe₃O₄ and C-Dots for degradation of mixture of toxic dyes, essential for large scale water treatment.

Near-Infrared Light-Initiated Photoelectrochemical Biosensor Based on Upconversion Nanorods for Immobilization-Free miRNA Detection with Double Signal Amplification

Photoelectrochemical (PEC) sensors are relatively new sensing platforms with high detection sensitivity and low cost. However, the current PEC biosensors dependent on ultraviolet or visible light as the exciting resource cause injuries to biological samples and systems, which restrains the applications in complicated matrixes. Herein, a near-infrared light (NIR)-initiated PEC biosensor based on NaYF₄:Yb,Tm@NaYF₄@TiO₂@CdS (csUCNRs@TiO₂@CdS) was constructed for sensitive detection of acute myocardial infarction (AMI)-related miRNA-133a in an immobilization-free format coupled with a hybridization chain reaction and a redox circle signal amplification strategy. A low-energy 980 nm NIR incident laser was converted to 300-480 nm light to excite the adjacent TiO₂@CdS photosensitive shell to generate photocurrent by NaYF₄:Yb,Tm@NaYF₄ upconversion nanorods. Also, magnetic beads were employed for the homogeneous determination of target miRNA-133a to reduce the recognition steric hindrance and improve the detection sensitivity. The photocurrent response was positively correlated with the level of ascorbic acid as the energy donor to consume photoacoustic holes produced on the surface of csUCNRs@TiO₂@CdS, which was generated by alkaline phosphatase catalyzation and regenerated by tris(2-carboxyethyl) phosphine reduction upon the appearance of miRNA-133a. Exerting a NIR-light-driven and immobilization-free strategy, the as-constructed biosensor displayed linearly sensitive and selective determination of miRNA-133a with a detection limit of 36.12 aM. More significantly, the assay method provided a new concept of the PEC sensing strategy driven by NIR light to detect diverse biomarkers with pronounced sensitivity, light stability, and low photodamage.

Surface Plasmon-Photon Coupling in Lanthanide-Doped Nanoparticles

Lanthanide-doped nanoparticles have great potential for energy conversion applications, as their optical properties can be precisely controlled by varying the doping composition, concentration, and surface structures, as well as through plasmonic coupling. In this Perspective we highlight recent advances in upconversion emission modulation enabled by coupling upconversion nanoparticles with well-defined plasmonic nanostructures. We emphasize fundamental understanding of luminescence enhancement, monochromatic emission amplification, lifetime tuning, and polarization control at nanoscale. The interplay between localized surface plasmons and absorbed photons at the plasmonic metal-lanthanide interface substantially enriches the interpretation of plasmon-coupled nonlinear photophysical processes. These studies will enable novel functional nanomaterials or nanostructures to be designed for a multitude of technological applications, including biomedicine, lasing, optogenetics, super-resolution imaging, photovoltaics, and photocatalysis.

CuS nanoparticles decorated MoS2 sheets as an efficient nanozyme for selective detection and photocatalytic degradation of hydroquinone in water

Cost effective and efficient CuS–MoS₂ nanocomposite with enhanced peroxidase enzyme mimetics and photocatalytic activity was synthesized by simple hydrothermal method and successfully utilized for sensing and detection of toxic hydroquinone molecules in aqueous medium.

Core-shell nanostructures: perspectives towards drug delivery applications

Nanosystems have shown encouraging outcomes and substantial progress in the areas of drug delivery and biomedical applications. However, the controlled and targeted delivery of drugs or genes can be limited due to their physicochemical and functional properties. In this regard, core-shell type nanoparticles are promising nanocarrier systems for controlled and targeted drug delivery applications. These functional nanoparticles are emerging as a particular class of nanosystems because of their unique advantages, including high surface area, and easy surface modification and functionalization. Such unique advantages can facilitate the use of core-shell nanoparticles for the selective mingling of two or more different functional properties in a single nanosystem to achieve the desired physicochemical properties that are essential for effective targeted drug delivery. Several types of core-shell nanoparticles, such as metallic, magnetic, silica-based, upconversion, and carbon-based core-shell nanoparticles, have been designed and developed for drug delivery applications. Keeping the scope, demand, and challenges in view, the present review explores state-of-the-art developments and advances in core-shell nanoparticle systems, the desired structure-property relationships, newly generated properties, the effects of parameter control, surface modification, and functionalization, and, last but not least, their promising applications in the fields of drug delivery, biomedical applications, and tissue engineering. This review also supports significant future research for developing multi-core and shell-based functional nanosystems to investigate nano-therapies that are needed for advanced, precise, and personalized healthcare systems.

Core-shell structured cadmium sulfide nanocomposites for solar energy utilization

Solar energy utilization technologies have been widely explored to solve the global energy crisis because the inexhaustible solar energy can be converted into chemical fuel and electricity. Various semiconductors that are crucial for solar energy utilization have been extensively developed. Among them, cadmium sulfide (CdS) has attracted extensive attention due to its suitable band-gap and excellent electrical/optical properties. However, CdS is still limited by rapid charge recombination, instability and low quantum efficiency. Core-shell structures can provide great opportunities for constructing advanced structures with superior properties to overcome the remaining challenges. This review focuses on the significant advances in core-shell structured CdS nanocomposites for solar energy utilization. Initially, the synthetic methods to construct core-shell structured CdS nanocomposites are reviewed. Then the applications in solar energy utilization are discussed, including photocatalytic\photoelectrochemical water splitting, photocatalytic CO₂ reduction and solar cells. Finally, the perspectives of core-shell structured CdS nanocomposites for solar energy utilization are proposed.

Low Toxicity, High Resolution, and Red Tissue Imaging in the Vivo of Yb/Tm/GZO@SiO2 Core-Shell Upconversion Nanoparticles

Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted great attention in bioimaging applications. However, the stability and resolution of bioimaging based on UCNPs should be further improved. Herein, we synthesized SiO₂-coated Ga(III)-doped ZnO (GZO) with lanthanide ion Yb(III) and Tm(III) (Yb/Tm/GZO@SiO₂) UCNPs, which realized red fluorescence imaging in heart tissue. With increasing injection concentrations of Yb/Tm/GZO@SiO₂ (1-10 mg/kg), the red fluorescence imaging intensity of heart tissue gradually increased. Moreover, the experimental results of toxicity in vitro and histological assessments of representative organs in vivo were studied, indicating that Yb/Tm/GZO@SiO₂ UCNPs had low biological toxicity. These results proved that Yb/Tm/GZO@SiO₂ can be used as a probe for fluorescence imaging in vivo.

Efficient Photocatalysis of Composite Films Based on Plasmon-Enhanced Triplet-Triplet Annihilation

To avoid secondary environmental pollution caused by photocatalysts in their applications, our work offers a new strategy for fabricating photocatalytic films based on plasmon-enhanced triplet-triplet annihilation upconversion (TTA-UC). Polydimethylsiloxane (PDMS) films containing platinum (II)-octaethylporphyrin and 9,10-diphenylanthracene (PtDPAP), and gold nanoparticles (AuNPs) were prepared. While graphene (G) was used as an adhesive and conductive layer, CdS nanoparticles were deposited onto the films (AuNPs-PtDPAP/G/CdS) by plasma glow discharge pretreatment. The AuNPs-PtDPAP film had an enhancement in the green-to-blue upconversion compared with the pristine PtDPAP film. CdS can utilize the AuNPs plasmon-enhanced TTA-UC photons to realize efficient photocatalytic reactions. The pseudo-first-order rate constant (k_pfo) of the optimized active and stable photocatalytic film, 0.3 AuNPs-PtDPAP/G/CdS, reached 0.294 h^-1 for tetracycline degradation under green light irradiation. Its k_pfo in decomposing tetracycline under visible light is 2.62 times higher than that of the PtDPAP/G/CdS. The reported composite films provide a strategy to improve the photocatalytic activity and promote the practical applications of nanosize photocatalysts.

Synthesis of alumina-based cross-linked chitosan–HPMC biocomposite film: an efficient and user-friendly adsorbent for multipurpose water purification

Novel alumina-based cross-linked chitosan–HPMC biocomposite is synthesized and its detailed characteristics with potential applications in water purification from both organic and inorganic contaminants elucidated.

Two-dimensional MoS2 nanosheet-modified oxygen defect-rich TiO2 nanoparticles for light emission and photocatalytic applications

MoS₂/TiO₂ nanohybrids efficiently decompose organic pollutants under sunlight due to the combined effects of defect creation and hetero-junction formation.