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For the first time, the dominant magnetoelectric activity of ZIF-67-derived carbonaceous microparticles embedded with Co nanoparticles and distinctive magnetothermal effect of MIL-88B-derived Fe3O4 nanocubes decorated on carbonaceous microrods, respectively, were explored to be controlled by the structure of the MOF-derived electrically conductive carbonaceous matrix and metal nanoparticles. [ABSTRACT FROM AUTHOR]

Herein, we successfully fabricated ultra-small metal nanoparticles into two stable Zr-based metal–organic frameworks via in situ redox reactions between triphenylamine and the corresponding metal ions to afford Pd NPs@1 and Pd NPs@2, which exhibit excellent activity and reusability for Suzuki coupling reactions as heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Analyst" published by the Royal Society of Chemistry. It includes a range of articles and papers on various topics related to chemistry and chemical sciences. Some of the topics covered include fluorescent carbon dots, metal nanoparticles, biosensing systems, nanoplastic detection, and electrochemical analysis. The journal aims to connect the global chemistry community and reinvest its profits back into the field. [Extracted from the article]

Emerging as a promising novel amplification technique, the exponential amplification reaction (EXPAR) offers significant advantages due to its potent exponential amplification capability, straightforward reaction design, rapid reaction kinetics, and isothermal operation. The past few years have witnessed swift advancements and refinements in EXPAR-based technologies, with numerous high-performance biosensing systems documented. A deeper understanding of the EXPAR mechanism has facilitated the proposal of novel strategies to overcome limitations inherent to traditional EXPAR. Furthermore, the synergistic integration of EXPAR with diverse amplification methodologies, including the use of a CRISPR/Cas system, metal nanoparticles, aptamers, alternative isothermal amplification techniques, and enzymes, has significantly bolstered analytical efficacy, aiming to enhance specificity, sensitivity, and amplification efficiency. This comprehensive review presents a detailed exposition of the EXPAR mechanism and analyzes its primary challenges. Additionally, we summarize the latest research advancements in the biomedical field concerning the integration of EXPAR with diverse amplification technologies for sensing strategies. Finally, we discuss the challenges and future prospects of EXPAR technology in the realms of biosensing and clinical applications. [ABSTRACT FROM AUTHOR]

Biosensors are currently among the most commonly used devices for analysing biomarkers and play an important role in environmental detection, food safety, and disease diagnosis. Researchers have developed multimodal biosensors instead of single-modal biosensors to meet increasing sensitivity, accuracy, and stability requirements. Metal nanoparticles (MNPs) are beneficial for preparing core probes for multimodal biosensors because of their excellent physical and chemical properties, such as easy regulation and modification, and because they can integrate diverse sensing strategies. This review mainly summarizes the excellent physicochemical properties of MNPs applied as biosensing probes and the principles of commonly used MNP-based multimodal sensing strategies. Recent applications and possible improvements of multimodal biosensors based on MNPs are also described, among which on-site inspection and sensitive detection are particularly important. The current challenges and prospects for multimodal biosensors based on MNPs may provide readers with a new perspective on this field. [ABSTRACT FROM AUTHOR]

Noble metal nanoparticles decorated on a catalyst support with a large specific surface area can exhibit enhanced catalytic activity. To this end, a synthetic method to heterogeneously and evenly nucleate platinum nanoparticles (Pt NPs) onto mesoporous silica nanoparticles (MSNs) is developed. The obtained Pt NP-modified MSNs (Pt-MSNs) are characterized as a thin layer of 3 nm-sized Pt NPs densely assembled on the MSN surface, by which the throughput of the peroxidase-like activity of Pt-MSNs is greatly improved. The utility of Pt-MSNs in colorimetric detection of analytes is validated for two different assay schemes. Firstly, colloidally dispersed Pt-MSNs are employed as a peroxidase-mimic in a two-step cascade reaction to quantitate glucose/cholesterol based on the amount of H2O2 produced by glucose/cholesterol oxidase. Secondly, detection of C-reactive protein (CRP) is conducted on a solid substrate by adopting a sandwich immunoassay format. Detection limits are estimated to be 20 μM, 55 μM, and 3.9 pM for glucose, cholesterol, and CRP, respectively. [ABSTRACT FROM AUTHOR]

Self-assembling short peptide amphiphiles, crafted through a minimalistic approach, spontaneously generate well-ordered nanostructures, facilitating the creation of precise nanostructured biomaterials for diverse biomedical applications. The seamless integration of bioactive metal ions and nanoparticles endows them with the potential to serve as pioneering materials in combating bacterial infections. Nanomanipulation of these molecules' binary structures enables effective penetration of membranes, forming structured nanoarchitectures with antibacterial properties. Through a comprehensive exploration, we attempt to reveal the innovative potential of short peptide amphiphiles, particularly in conjugation with metal cations and nanoparticles, offering insights for future research trajectories. [ABSTRACT FROM AUTHOR]

To respond to the increasing demands for practical applications, stabilization and property modulation of metal nanoparticles have emerged as a key research subject. Herein, we present a viable protocol for preparing small metal nanoparticles (<5 nm; Ag, Pd, Pt, and Ru) via multidentate polyoxometalate (POM, [SiW9O34]10−) modification. In addition to enhancing stability, the POMs can modulate the electronic states of metal nanoparticles. Moreover, immobilization of the POM-modified metal nanoparticles on solid supports enables further tuning of the electronic states via a cooperative effect between the POMs and the supports without altering the particle size. Notably, POM-modified Pd nanoparticles on carbon support exhibited superior catalytic activity and selectivity in hydrogenation reactions in comparison with the catalyst without the POM modification. [ABSTRACT FROM AUTHOR]

Proteins are an eminently important class of ubiquitous biomacromolecules with diverse biological functions, and numerous techniques for their detection, quantification, and localisation have been developed. Many of these methods exploit the selectivity arising from molecular recognition of proteins/antigens by immunoglobulins. The combination of surface-enhanced Raman scattering (SERS) with such "immuno"-techniques to immuno-SERS (iSERS) is the central topic of this review, which is focused on colloidal SERS nanotags, i.e., molecularly functionalised noble metal nanoparticles conjugated to antibodies, for their use in protein assays and ex vivo imaging. After contrasting the fundamental differences between label-free SERS and iSERS, including a balanced description of the advantages and drawbacks of the latter, we describe the usual workflow of iSERS experiments. Milestones in the development of the iSERS technology are summarised from a historical perspective. By highlighting selected examples from the literature, we illustrate the conceptual progress that has been achieved in the fields of iSERS-based protein assays and ex vivo imaging. Finally, we attempt to predict what is necessary to fully exploit the transformative potential of the iSERS technology by stimulating the transition from research in academic labs into applications for the benefit of our society. [ABSTRACT FROM AUTHOR]

The ability of NaCl-type binary transition metal nitrides (incorporating La, Ce, Y, Zr or Hf) to act as catalytic supports facilitating ammonia decomposition was examined. The effect of nitrogen vacancies formed on nitrides can be understood in terms of the ionic radii of the metal cations. A clear correlation between the N2 desorption temperature and catalytic activity was found. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (MNPs) composited on metal–organic frameworks (MOFs) can generate valuable materials (MNP/MOF) possessing good physical, chemical, and biological properties. The preparation of novel MNP/MOF followed by exploration of their applications has inspired great investigational enthusiasm. In this paper, Ni, Co and Ni–Co bimetallic MNP/MOF catalysts derived from MOFs were prepared by controlled pyrolysis, and then characterized by TGA, FTIR, XRD, BET, SEM, XPS and H2-TPD, which showed that pyrolysis under H2 (reported typically under an inert atmosphere) and the addition of Co to Ni–MOF could form Ni–Co alloy MOFs with not only a relatively complete MOFs structure but good dispersion of metal nanoparticles. In order to disclose their potential for utilization, specifically, the activity tests of the prepared novel MNP/MOF materials were conducted on the hydrogenation of toluene towards methylcyclohexane. The results confirmed that the Ni1Co2/MOF-325 catalyst obtained by pyrolysis of Ni1Co2–MOF under H2 at 325 °C had high activity and good stability for the hydrogenation of toluene, showing excellent prospect as a hydrogenation catalyst. [ABSTRACT FROM AUTHOR]

The theoretically infinite compositional space of high-entropy alloys (HEAs) and their novel properties and applications have attracted significant attention from a broader research community. The successful synthesis of high-quality single-phase HEA nanoparticles represents a crucial step in fully unlocking the potential of this new class of materials to drive innovations. This review analyzes the various methods reported in the literature to identify their commonalities and dissimilarities, which allows categorizing these methods into five general strategies. Physical minimization of HEA metals into HEA nanoparticles through cryo-milling represents the typical top–down strategy. The counter bottom–up strategy requires the simultaneous generation and precipitation of metal atoms of different elements on growing nanoparticles. Depending on the metal atom generation process, there are four synthesis strategies: vaporization of metals, burst reduction of metal precursors, thermal shock-induced reduction of metal precursors, and solvothermal reduction of metal precursors. Comparisons among the methods within each strategy, along with discussions, provide insights and guidance for achieving the robust synthesis of HEA nanoparticles. [ABSTRACT FROM AUTHOR]

The upgrading of a benzyl-type alcohols was explored via an orthogonal tandem sequence comprised of a first oxidative step producing the corresponding aldehydes, and a subsequent reductive amination to achieve both secondary and tertiary amines. To the scope, acetonitrile (ACN) was used as a solvent and a source/precursor of reactant amines, and different heterogeneous catalysts based on Rh and Mo, were designed as mono- and bi-metallic systems in the form of metal nanoparticles dispersed on a chitinderived N-doped carbons. A parametric analysis carried out separately for the oxidation and the reductive amination allowed to choose the best performant catalyst for both the reactions of the tandem process. A one-pot two-step protocol was implemented accordingly: as an example, benzyl alcohol was quantitatively and selectively oxidised to benzaldehyde (>99%) which in turn, was converted to N-benzylethanamine (66%) or N-benzyl-N-ethylethanamine (60%) in the presence of [Rh(5%)-N/C--Mo (5%)]-N/C or [Rh(3%)-N/C--Mo(5%)]-N/C as catalysts, respectively. The tandem sequence proved successful also for other bio-based benzyl-type alcohols that afforded the corresponding secondary/tertiary amines in yields up to 53--93%. Overall, the study proved the viability of an innovative method aimed not only at process intensification for multistep synthesis, but also at the valorization of substrates (alcohols) and biopolymers (chitin) derived from biomass. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial evaporation technology has great potential in solving the global challenge of freshwater shortage. However, the selection of excellent photothermal conversion materials is a challenging task. To achieve efficient solar interface evaporation materials, we developed a new material loaded with Fe/Fe3C nanoparticles on mesoporous carbon hollow spheres (MCHSs). As an interfacial evaporation material, Fe/Fe3C@MCHS-x has an evaporation rate of 1.633 kg m−2 h−1 and an energy conversion efficiency of 94.17% (Fe/Fe3C@MCHS-2). The innovative introduction of magnetic particles into the evaporation unit allows the metal nanoparticles to absorb light at their resonance wavelength. This absorption leads to the excitation of electrons from the occupied state to the unoccupied state, and the diffusion of thermoelectrons leads to an increase of carriers, which makes the interface temperature rise rapidly. The composite material has a certain degree of organic pollution treatment capability along with high-efficiency water evaporation, which provides new ideas for interfacial evaporation material technology. [ABSTRACT FROM AUTHOR]

The preparation of ultra-small and well-dispersed metal nanoparticles (NPs) is of great importance for promoting oxygen reduction. Here, a metal (Fe and Zn) NP (7 nm) based catalyst derived from a Zn-based metal–organic framework was obtained by a vapor adsorption strategy, demonstrating a high half-wave potential (0.868 V) and power density (196 mW cm−2). [ABSTRACT FROM AUTHOR]

Improving the dispersion of metal nanoparticles and suppressing metal aggregation have long been the keys to constructing efficient metal-loaded catalysts. Herein, catalysts of cobalt (Co) supported on nitrogen (N)-doped carbon were prepared by a simple hydrothermal method using folic acid (FA) as the carbon source. Surprisingly, hydrazine hydrate not only facilitated the loading of metal Co, but also regulated the morphology of the catalyst, promoted the uniform distribution of metal Co, and effectively improved the catalytic hydrogenation activity of the catalyst. It was found that the catalyst mediated with 10 mL hydrazine hydrate and pyrolyzed at 900 °C exhibited the best catalytic performance (99.6% conversion of quinoline and 98.0% selectivity for 1,2,3,4-tetrahydroquinoline). In addition, it exhibited satisfying adaptability for diverse substrates. This study can provide great theoretical significance and practical guidance for the preparation of Co–N–C catalysts. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4), as a carbon support material with excellent stability and abundant active sites, has found widespread applications in various fields, including photocatalytic water splitting, electrolysis of water, and CO2 reduction. Presently, research on the modification of g-C3N4 primarily focuses on atomic doping, defect engineering, and the decoration of metal nanoparticles. In this study, a method involving the high-temperature pyrolysis of a solution containing thiourea and urea was successfully employed to synthesize sulfur-doped porous g-C3N4 (S-C3N4) nanosheets. Subsequently, PtCu nanoparticles were loaded onto the S-C3N4 through a hydrothermal process. In the case of Pt loading of less than half of 20% Pt/C, this catalyst exhibited a low overpotential of only 10 mV at a current density of 10 mA cm−2, which is significantly better than the 35 mV overpotential of 20% Pt/C. Furthermore, after a long period of continuous current stability testing, the overpotential of the catalyst did not increase by more than 30 mV, demonstrating excellent stability. The porous S-C3N4 nanosheets possess a large specific surface area, providing abundant active sites for the HER reaction. This research introduces a fresh method for creating innovative catalysts based on Pt alloys supported by a carbon carrier. [ABSTRACT FROM AUTHOR]

Porous nanoparticles integrating the advantages of porosity and structural coherence typically possess numerous active sites confined on their surfaces. In this study, porous Co3O4, Fe2O3 and Fe3O4 nanoparticles are synthesised by one-step pyrolysis from metal–organic frameworks (MIL-101 (Fe) and ZIF-67 (Co)) to test the performance of CO oxidation. The prepared porous nanoparticles have uniform and stable porous structures without obvious shrinkage and structural collapse. The best catalytic performance was achieved by the porous Co3O4 nanoparticles, which reached 100% CO conversion at 130 °C without any decay in catalytic activity after 48 h of reaction. DRIFTS results present the mechanism of the CO oxidation by porous Co3O4 nanoparticle catalysis. The excellent catalytic activity of the porous Co3O4 nanoparticles is related to the large specific surface area and surface oxygen vacancies. This work provides a design approach for synthesizing other porous metal oxide nanoparticles and has reference value in the field of CO oxidation. [ABSTRACT FROM AUTHOR]

Herein, microemulsion mediated controlled lanthanide metal based nanoparticles are employed in the preparation of a pH responsive Pickering emulsion. Lanthanum sulfide (LaS) nanoparticles are synthesised in the core of a water-in-oil microemulsion, prepared by Tween 80/1-butanol/water/toluene. The TEM images obtained, were used to evaluate the stages of the progress of nanosphere preparation. Novel oil-in-water (O/W) Pickering emulsions have been produced with the assistance of negatively charged, size and shape regulated lanthanum sulfide nanoparticles (0.05 wt%) and an adequate amount of a cationic CTAB surfactant. Adsorption of an ionic surfactant onto the surface of oppositely charged nanoparticles typically occurs in slightly acidic or neutral environments (pH 5.33 to 6.16), converting hydrophilic nanoparticles to hydrophobic ones through in situ hydrophobization. Because the emulsions are sensitive to pH alterations, an effective demulsification can be accomplished by pH changes. Demulsification occurs at two distinct pH ranges: a lower pH (3.50) and a higher pH (10.50). Surfactant molecules are desorbed from the surfaces of nanoparticles at these two pH ranges, causing the particles to revert to their hydrophilic form. Desorption of hydrophilic nanoparticles from the water–oil interface caused the Pickering emulsion to become unstable. Remulsification is achieved by just adjusting the pH with the addition KOH or HCl. It is feasible to produce eight consecutive cycles of emulsification and demulsification by just changing the pH. Thus, by using size- and shape-controlled nanoparticles, this study introduces an entirely new scientific perspective on the synthesis of distinct characteristics (likewise to pH responsiveness) of the Pickering emulsion. [ABSTRACT FROM AUTHOR]

Carbon dots@noble metal nanoparticle composites are formed by combining carbon dots and metal nanoparticles using various strategies. Carbon dots exhibit a reducing ability and function as stabilisers; consequently, metal-ion solutions can be directly reduced by them to synthesise gold, silver, and gold–silver alloy particles. Carbon dots@gold/silver/gold–silver particle composites have demonstrated the potential for several practical applications owing to their superior properties and simple preparation process. Until now, several review articles have been published to summarise fluorescent carbon dots or noble metal nanomaterials. Compared with metal-free carbon dots, carbon dots@noble metal nanoparticles have a unique morphology and structure, resulting in new physicochemical properties, which allow for sensing, bioimaging, and bacteriostasis applications. Therefore, to promote the effective development of carbon dots@noble metal nanoparticle composites, this paper primarily reviews carbon dots@gold/silver/gold–silver alloy nanoparticle composites for the first time in terms of the following aspects. (1) The synthesis strategies of carbon dots@noble metal nanoparticle composites are outlined. The principle and function of carbon dots in the synthesis strategies are examined. The advantages and disadvantages of these methods and composites are analysed. (2) The characteristics and properties of such composites are described. (3) The applications of these composite materials are summarised. Finally, the potentials and limitations of carbon dots@noble metal nanoparticle composites are discussed, thus laying the foundation for their further development. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) are highly efficient and environmentally friendly devices for converting fuel into electrical energy. In this regard, metal nanoparticles (NPs) loaded onto the anode oxide play a crucial role due to their exceptional catalytic activity. NPs synthesized through exsolution exhibit excellent dispersion and stability, garnering significant attention for comprehending the exsolution process mechanism and consequently improving synthesis effectiveness. This review presents recent advancements in the exsolution process, focusing on the influence of oxygen vacancies, A-site defects, lattice strain, and phase transformation on the variation of the octahedral crystal field in perovskites. Moreover, we offer insights into future research directions to further enhance our understanding of the mechanism and achieve significant exsolution of NPs on perovskites. [ABSTRACT FROM AUTHOR]

With the rapid development of fluorescent nanoparticles (FNPs), such as CDs, QDs, and MOFs, the construction of FNP-based probes has played a key role in improving chemical sensors. Ratiometric fluorescent probes exhibit distinct advantages, such as resistance to environmental interference and achieving visualization. Thus, FNP-based dual-emission ratiometric fluorescent probes (DRFPs) have rapidly developed in the field of metal ion and small molecule detection in the past few years. In this review, firstly we introduce the fluorescence sensing mechanisms; then, we focus on the strategies for the fabrication of DRFPs, including hybrid FNPs, single FNPs with intrinsic dual emission and target-induced new emission, and DRFPs based on auxiliary nanoparticles. In the section on hybrid FNPs, methods to assemble two types of FNPs, such as chemical bonding, electrostatic interaction, core satellite or core–shell structures, coordination, and encapsulation, are introduced. In the section on single FNPs with intrinsic dual emission, methods for the design of dual-emission CDs, QDs, and MOFs are discussed. Regarding target-induced new emission, sensitization, coordination, hydrogen bonding, and chemical reaction induced new emissions are discussed. Furthermore, in the section on DRFPs based on auxiliary nanoparticles, auxiliary nanomaterials with the inner filter effect and enzyme mimicking activity are discussed. Finally, the existing challenges and an outlook on the future of DRFP are presented. We sincerely hope that this review will contribute to the quick understanding and exploration of DRFPs by researchers. [ABSTRACT FROM AUTHOR]

The conjugation of DNA molecules with metal or metal-containing nanoparticles (M/MC NPs) has resulted in a number of new hybrid materials, enabling a diverse range of novel biological applications in nanomaterial assembly, biosensor development, and drug/gene delivery. In such materials, the molecular recognition, gene therapeutic, and structure-directing functions of DNA molecules are coupled with M/MC NPs. In turn, the M/MC NPs have optical, catalytic, pore structure, or photodynamic/photothermal properties, which are beneficial for sensing, theranostic, and drug loading applications. This review focuses on the different DNA functionalization protocols available for M/MC NPs, including gold NPs, upconversion NPs, metal–organic frameworks, metal oxide NPs and quantum dots. The biological applications of DNA-functionalized M/MC NPs in the treatment or diagnosis of cancers are discussed in detail. [ABSTRACT FROM AUTHOR]

We propose a universal, green, and surfactant-free strategy to synthesize noble metal particles with high monodispersity using gaseous H2 as a reducing agent in a solution at 60 °C. The prepared Pt nanoparticles have a 24 mV more positive half-wave potential than the commercially available Pt/C in the oxygen reduction reaction, while showing high durability with negligible half-wave potential decay after 10 000 cycles of testing. [ABSTRACT FROM AUTHOR]

Palladium nanoparticles find extensive applications in catalysis in both homogeneously and heterogeneously catalyzed processes. Supporting metal nanoparticles enhances their stability as compared to their unsupported counterparts. The role of catalytic support is increasingly recognized as crucial in determining the behaviour of these materials. However, controlling the deposition and anchoring of palladium nanoparticles remains a significant challenge. This contribution discusses the preparation of straight lines of palladium particles on zinc oxide by wet impregnation. This phenomenon is attributed to the highly stepped morphology of the employed ZnO that created steric anchoring sites to stabilize the metal particles. Palladium-based catalysts were evaluated for the valuable Suzuki–Miyaura cross-coupling reaction. The dispersed Pd/ZnO catalyst achieved a conversion rate of 86% with 100% selectivity, remarkably superior to that of the Pd/Al2O3 and Pd/TiO2 counterparts. [ABSTRACT FROM AUTHOR]

Ensuring food safety is a critical concern for the development and well-being of humanity, as foodborne illnesses caused by foodborne bacteria have increasingly become a major public health concern worldwide. Traditional food safety monitoring systems are expensive and time-consuming, relying heavily on specialized equipment and operations. Therefore, there is an urgent need to develop low-cost, user-friendly and highly sensitive biosensors for detecting foodborne bacteria. In recent years, the combination of nanomaterials with optical biosensors has provided a prospective future platform for the detection of foodborne bacteria. By harnessing the unique properties of nanomaterials, such as their high surface area-to-volume ratio and exceptional sensitivity, in tandem with the precision of optical biosensing techniques, a new prospect has opened up for the rapid and accurate identification of potential bacterial contaminants in food. This review focuses on recent advances and new trends of nanomaterial-based biosensors for the detection of foodborne pathogens, which mainly include noble metal nanoparticles (NMPs), metal organic frameworks (MOFs), graphene nanomaterials, quantum dot (QD) nanomaterials, upconversion fluorescent nanomaterials (UCNPs) and carbon dots (CDs). Additionally, we summarized the research progress of color indicators, nanozymes, natural enzyme vectors and fluorescent dye biosensors, focusing on the advantages and disadvantages of nanomaterial-based biosensors and their development prospects. This review provides an outlook on future technological directions and potential applications to help identify the most promising areas of development in this field. [ABSTRACT FROM AUTHOR]

As nanotechnology continues to push the boundaries across disciplines, there is an increasing need for engineering nanomaterials with atomic-level precision for self-assembly across length scales, i.e., from the nanoscale to the macroscale. Although molecular self-assembly allows atomic precision, extending it beyond certain length scales presents a challenge. Therefore, the attention has turned to size and shape-controlled metal nanoparticles as building blocks for multifunctional colloidal self-assemblies. However, traditionally, metal nanoparticles suffer from polydispersity, uncontrolled aggregation, and inhomogeneous ligand distribution, resulting in heterogeneous end products. In this feature article, I will discuss how virus capsids provide clues for designing subunit-based, precise, efficient, and error-free self-assembly of colloidal molecules. The atomically precise nanoscale proteinic subunits of capsids display rigidity (conformational and structural) and patchy distribution of interacting sites. Recent experimental evidence suggests that atomically precise noble metal nanoclusters display an anisotropic distribution of ligands and patchy ligand bundles. This enables symmetry breaking, consequently offering a facile route for two-dimensional colloidal crystals, bilayers, and elastic monolayer membranes. Furthermore, inter-nanocluster interactions mediated via the ligand functional groups are versatile, offering routes for discrete supracolloidal capsids, composite cages, toroids, and macroscopic hierarchically porous frameworks. Therefore, engineered nanoparticles with atomically precise structures have the potential to overcome the limitations of molecular self-assembly and large colloidal particles. Self-assembly allows the emergence of new optical properties, mechanical strength, photothermal stability, catalytic efficiency, quantum yield, and biological properties. The self-assembled structures allow reproducible optoelectronic properties, mechanical performance, and accurate sensing. More importantly, the intrinsic properties of individual nanoclusters are retained across length scales. The atomically precise nanoparticles offer enormous potential for next-generation functional materials, optoelectronics, precision sensors, and photonic devices. [ABSTRACT FROM AUTHOR]

Metal nanoclusters (NCs) with sizes of approximately 2 nm or less have different physical/chemical properties from those of the bulk metals owing to quantum size effects. Metal NCs, which can be size-controlled and heterometal doped at atomic accuracy, are expected to be the next generation of important materials, and new metal NCs are reported regularly. However, compared with conventional materials such as metal complexes and relatively large metal nanoparticles (>2 nm), these metal NCs are still underdeveloped in terms of evaluation and establishment of application methods. Electrochemical measurements are one of the most widely used methods for synthesis, application, and characterisation of metal NCs. This review summarizes the basic knowledge of the electrochemistry and experimental techniques, and provides examples of the reported electronic states of thiolate-protected gold NCs elucidated by electrochemical approaches. It is expected that this review will provide useful information for researchers starting to study metal NCs. [ABSTRACT FROM AUTHOR]

N-doped carbon materials are known for their high conductivity, rich N content, and high adsorption activity. When combined with Fe2O3 to form nanocomposites, they can improve the conductivity of Fe2O3 and cause significant changes in the electrochemical sensing interface with the influence of their unique electronic structure. In this work, N-doped carbon nanocomposites (Fe2O3@NCNPs-x) modified with Fe2O3 nanoparticles (Fe2O3 NPs) were synthesized by a simple emulsion polymerization method and carbonized under Ar at a high temperature. X-ray photoelectron spectroscopy indicated that compared with undoped Fe2O3 NPs, the π bond of Fe2O3@NCNPs-1.5 was negatively charged due to the lone pair of electrons near the N atom, acting as an electron donor that enhanced the interaction with HMIs and electron transport, therefore generating more active sites on the surface of Fe2O3@NCNPs-1.5. The obtained Fe2+/Fe3+ ratio was about two times higher than that of undoped Fe2O3 NPs (Fe2O3@NCNPs-1.5: Fe2+/Fe3+ = 1.24; Fe2O3 NPs: Fe2+/Fe3+ = 0.61). The surface oxygen vacancy (OV) concentration reached the maximum level (Fe2O3@NCNPs-1.5: OVs/O1s = 41.7%; Fe2O3 NPs: OVs/O1s = 22%). Fe2O3@NCNPs-1.5/GCE also showed enhanced electrochemical performance for detecting Pb2+ and Cd2+, with a limit of detection (LOD, S/N = 3) of 4.92 and 18.79 nM, respectively. Electrochemical adsorption tests suggested that Fe2O3@NCNPs-1.5/GCE had the strongest adsorption capacity for Pb2+ and Cd2+ in comparison with other modified electrodes, suggesting that different N contents led to different absorbability for heavy metal ions (HMIs). Therefore, when the metal oxide nanoparticles are loaded on compatible carriers, the jointly constructed nanocomposites can be used as the active materials for efficiently detecting HMIs, providing a new concept for designing highly active electrochemical sensors. [ABSTRACT FROM AUTHOR]

N-doped carbon materials are known for their high conductivity, rich N content, and high adsorption activity. When combined with Fe2O3 to form nanocomposites, they can improve the conductivity of Fe2O3 and cause significant changes in the electrochemical sensing interface with the influence of their unique electronic structure. In this work, N-doped carbon nanocomposites (Fe2O3@NCNPs-x) modified with Fe2O3 nanoparticles (Fe2O3 NPs) were synthesized by a simple emulsion polymerization method and carbonized under Ar at a high temperature. X-ray photoelectron spectroscopy indicated that compared with undoped Fe2O3 NPs, the π bond of Fe2O3@NCNPs-1.5 was negatively charged due to the lone pair of electrons near the N atom, acting as an electron donor that enhanced the interaction with HMIs and electron transport, therefore generating more active sites on the surface of Fe2O3@NCNPs-1.5. The obtained Fe2+/Fe3+ ratio was about two times higher than that of undoped Fe2O3 NPs (Fe2O3@NCNPs-1.5: Fe2+/Fe3+ = 1.24; Fe2O3 NPs: Fe2+/Fe3+ = 0.61). The surface oxygen vacancy (OV) concentration reached the maximum level (Fe2O3@NCNPs-1.5: OVs/O1s = 41.7%; Fe2O3 NPs: OVs/O1s = 22%). Fe2O3@NCNPs-1.5/GCE also showed enhanced electrochemical performance for detecting Pb2+ and Cd2+, with a limit of detection (LOD, S/N = 3) of 4.92 and 18.79 nM, respectively. Electrochemical adsorption tests suggested that Fe2O3@NCNPs-1.5/GCE had the strongest adsorption capacity for Pb2+ and Cd2+ in comparison with other modified electrodes, suggesting that different N contents led to different absorbability for heavy metal ions (HMIs). Therefore, when the metal oxide nanoparticles are loaded on compatible carriers, the jointly constructed nanocomposites can be used as the active materials for efficiently detecting HMIs, providing a new concept for designing highly active electrochemical sensors. [ABSTRACT FROM AUTHOR]

Hydrodeoxygenation of lignin-derived phenolic compounds to produce alkanes is a promising method used for mitigating fossil energy consumption, but they often require high temperature and high pressure, resulting in their poor catalytic stability and durability. In this study, we encapsulated ∼3.9 nm active metal Rh nanoparticles (NPs) into ∼40 nm hollow mesoporous aluminosilicate nanospheres (HMANs) to synthesize M@Alx–mSiO2 nanoreactors with adjustable Al contents for guaiacol hydrodeoxygenation. The optimized Rh@Al2.0–mSiO2 catalyst displayed significantly enhanced guaiacol activity and cyclohexane selectivity relative to the Rh@mSiO2 catalyst under mild reaction conditions. According to the characterization results, 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, and the introduction of Al species greatly facilitated the adsorption of 2-methylcyclohexanol, thereby enhancing cyclohexane selectivity. The confinement effect of Rh NPs inside the hollow cavities effectively prevents the leaching and aggregation of Rh NPs, thereby improving their catalytic durability and stability. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET), as the most widely utilized polyester, causes global environmental problems due to its massive and durable accumulation in natural environments. The glycolysis of PET is an attractive alternative to mechanical recycling, but there remains a strong demand for efficient, convenient, and inexpensive catalysts. Herein, we present a spray-drying-assisted way to construct magnetic hollow micro-sized nanoaggregates (HMNAs) by assembling composite metal oxide nanoparticles to depolymerize PET synergistically. The as-prepared ZnO–Fe3O4 HMNAs completely depolymerized PET with a high monomer yield of 92.3% in a short period of 30 min at 190 °C, far above individual ZnO and Fe3O4 nanoparticles (NPs). The composite HMNAs can be magnetically separated in a few minutes and maintain a high activity for 5 cycles. DFT study reveals that the HMNAs effectively facilitated glycolysis by the high content of Lewis acid sites as well as the stronger adsorption between PET and the catalyst owing to the structural synergy effect of ZnO–Fe3O4 HMNAs. Furthermore, this spray drying strategy as a versatile and scalable methodology is extended to fabricate other HMNAs, exhibiting a similarly enhanced efficiency of glycolysis. The HMNAs are expected to open up avenues for the design of catalysts for upcycling of discarded plastics. [ABSTRACT FROM AUTHOR]

Solar-driven interfacial evaporation (SDIE) technology has evolved rapidly in the last decade and is an exciting scientific topic. With this high level of attention, it is necessary to continuously summarize previous research to develop SDIE technology well. Therefore, we have prepared this review article to summarize the latest progress in this field. First, photothermal conversion materials are introduced, which play an essential role in SDIE, including plasma metal nanoparticles, semiconductors, and carbon-based and polymer-based materials, and their photothermal mechanisms are explained. Second, strategies to improve SDIE performances, such as enhanced light absorption, water transmission channel design, and thermal management, are discussed, which can well modulate the evaporator performance and improve energy utilization efficiency. Subsequently, the applications of SDIE in various aspects including desalination, sterilization, sewage treatment, and simultaneous generation of water and electricity are presented in detail. At the end, we summarize some of the current bottlenecks encountered by SDIE, offer some insights into the ideal SDIE evaporator, and provide an outlook on the future development of SDIE technology. The potential of SDIE is being demonstrated in a variety of applications and it promises to be a green, economical solution to energy and water shortage problems in the future. This review aims to promote the research and practical application of SDIE and contribute to its development. [ABSTRACT FROM AUTHOR]

The electroreduction of CO2 (CO2RR) is a sustainable approach to mitigate the increased global CO2 emissions and further produce valuable chemicals. Electrocatalysts are crucial to lower the energy barrier, tune the intricate reaction pathways and suppress the competitive side-reactions. In this feature article, we give a brief overview of our journey in the design of efficient catalysts for the CO2RR. From bulk metals to nanoparticles to single-atom catalysts (SACs), we summarize our progress in the design of efficient metal nanoparticles by porosity engineering, defect engineering and alloy engineering, and developing single-atom catalysts with advanced metal sites, coordination environments, substrates and synthesis routes. We highlight the importance of reaction environments and provide an ionic liquid nanoconfinement strategy for local environment modification. In the end, we provide our views and perspectives for the future direction of the CO2RR towards commercialization. [ABSTRACT FROM AUTHOR]

The electroreduction of CO2 (CO2RR) is a sustainable approach to mitigate the increased global CO2 emissions and further produce valuable chemicals. Electrocatalysts are crucial to lower the energy barrier, tune the intricate reaction pathways and suppress the competitive side-reactions. In this feature article, we give a brief overview of our journey in the design of efficient catalysts for the CO2RR. From bulk metals to nanoparticles to single-atom catalysts (SACs), we summarize our progress in the design of efficient metal nanoparticles by porosity engineering, defect engineering and alloy engineering, and developing single-atom catalysts with advanced metal sites, coordination environments, substrates and synthesis routes. We highlight the importance of reaction environments and provide an ionic liquid nanoconfinement strategy for local environment modification. In the end, we provide our views and perspectives for the future direction of the CO2RR towards commercialization. [ABSTRACT FROM AUTHOR]

In the present work, we have developed a reduced graphene oxide (rGO)-supported palladium nanoparticle (Pd NP)-based nanocatalyst that can smoothly promote Suzuki–Miyaura and Heck–Matsuda coupling reactions from diazoarenes under base- and ligand-free conditions with low palladium loadings (ppm level). The as-synthesized catalyst (Pd@rGO) was comprehensively characterized by TEM, EDX, FT-IR, PXRD, TGA, ICP-OES and RAMAN analysis. Interestingly, the catalyst was also found to be effective in chemoselective double Suzuki–Miyaura cross-coupling reaction for the synthesis of various terphenyl derivatives in one-pot operation. The catalytic application of Pd@rGO was also extended to prepare Boscalid, a well-known fungicide. Additionally, the catalyst could be reused six times without much loss of activity. [ABSTRACT FROM AUTHOR]

Hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a key reaction in the conversion of biomass to renewable fuels and value-added chemicals. Developing low-cost, highly efficient and reusable non-noble metal-based heterogeneous catalysts is vital but challenging. Herein, non-noble Ni–Mn/SiO2 catalysts with a low Ni loading (2.0 wt%) were designed for the selective hydrogenation of LA to GVL. The results showed that the optimal Ni–Mn/SiO2 (Ni/Mn = 2) catalyst with well-dispersed and small-sized metal nanoparticles (2.21 nm) and moderate acid sites exhibited excellent activity and selectivity and achieved a 100% yield of GVL in a 1,4-dioxane solvent under mild reaction conditions (e.g., 0.8 mol% Ni, 140 °C and 2.0 MPa H2) for 5.5 h and a 100% GVL yield at 180 °C for 2 h with a turnover frequency (TOF) of 190.2 h−1, which is better than most non-noble metal catalysts reported. Furthermore, the catalyst exhibited excellent reusability and could be recycled at least five times with only slight activity loss. This work provides new insights for the rational design of highly efficient and stable non-noble metal catalysts for the conversion of LA to GVL. [ABSTRACT FROM AUTHOR]

This study reports the synthesis and characterization of two new mono- and di-substituted phthalonitriles namely 4-((9H-carbazol-3-yl)oxy)-5-chlorophthalonitrile and 4,5-bis((9H-carbazol-3-yl)oxy)phthalonitrile, respectively. Cyclotetramerization of the new phthalonitriles in the presence of zinc(II) acetate resulted in related zinc(II) phthalocyanines. To study the effect of the position and number of substituents on the biological properties of the phthalocyanines, peripherally or non-peripherally tetra-substituted zinc(II) phthalocyanines bearing (9H-carbazol-3-yl)oxy groups, as well as axially di-substituted silicon phthalocyanines containing the same groups, were prepared. Since gold nanoparticles are well-known as efficient drug delivery agents, the surface of these metal nanoparticles was functionalized with all the compounds. This modification also improved the solubility of the phthalocyanines in aqueous media. In this study, the antioxidant, DNA cleavage, and toxic/phototoxic activities of the resultant nanoconjugates were examined. With a combination of metal ion and substituent (nature, number, and position) effects, the silicon(IV) phthalocyanine exhibited the highest biological properties. [ABSTRACT FROM AUTHOR]

Hydrogen production by water-splitting is a very promising strategic energy technology and one of the most important means to obtain green hydrogen. It is of great practical significance to develop cheap and efficient electrocatalysts to replace Pt. Herein, we use the dye-sensitization strategy to load hyperdispersed Ru nanoparticles on the TiO2 surface, and then use cheap glucose for carbon coating to improve the conductivity of the material, so as to obtain an efficient HER catalyst C/Ru/TiO2. On the one hand, dye molecules can be firmly bonded to the surface of TiO2 through carboxyl groups, and on the other hand, their large steric effect can effectively inhibit the aggregation of molecules, so ruthenium nanoparticles formed after pyrolysis can be uniformly distributed on the surface of TiO2. Carbon coating also effectively solves the problem of poor conductivity of TiO2 as a support. C/Ru/TiO2 shows excellent catalytic performance for HER. In 0.5 M H2SO4, the overpotential is 69 mV at 10 mA cm−2 and the Tafel slope is only 70 mV dec−1. In 1 M KOH, the overpotential is only 51 mV at 10 mA cm−2 and the Tafel slope is only 68 mV dec−1. The dye-sensitization strategy makes it easy to realize the loading of hyperdisperse metal nanoparticles on the support surface. [ABSTRACT FROM AUTHOR]

In this study, we synthesized novel bipyridine-based, sp2-carbon-linked COFs with the incorporation of ultra-small metal nanoparticles for enhanced photocatalytic tetracycline hydrochloride degradation and hydrogen evolution. The obtained photocatalyst exhibits strong visible light absorption and modulated electronic structure, owing to charge transfer between the metal and COFs, resulting in tuned proton absorption/desorption energy. As a result, the Pd-COFs exhibit remarkable photocatalytic activities for both tetracycline hydrochloride removal and hydrogen evolution. Specifically, the rate constant of photocatalytic tetracycline hydrochloride removal reaches 0.03406 min−1 with excellent stability and the photocatalytic hydrogen evolution rate reaches 98.17 mmol g−1 h−1, outperforming the-state-of-the-art photocatalysts with noble Pt loading. [ABSTRACT FROM AUTHOR]

A scalable and facile solid-catalyzed growth approach is reported to integrate N-doped carbon tentacles with metal selenide nanoparticles, showing great potential for mass production of non-precious metal catalysts for rechargeable Zn–air batteries. [ABSTRACT FROM AUTHOR]

Carbon-incorporated metal nanoparticles are heat-treated in various gas atmospheres to create carbon shells with different porosity. A highly porous carbon shell is formed due to the carbon etching effect by H2, and the defect healing effect by CO is discovered through additional CO gas treatment of the H2/N2 gas-treated sample. [ABSTRACT FROM AUTHOR]

Biofilms are complex environments where matrix effects from components such as extracellular polymeric substances and proteins can strongly affect SERS performance. Here the interactions between SERS-enhancing Ag and Au particles were studied using ex situ biofilms (es-biofilms), which were more homogenous than in situ biofilm samples. This allowed systematic quantitative studies, where samples could be accurately diluted and analysed, to be carried out. Strong signals from intrinsic marker compounds were found for the Pseudomonas aeruginosa and Staphylococcus aureus extracted es-biofilms, which the standard addition method showed were due to 2 × 10–3 mol dm−3 pyocyanin or the equivalent of 1 × 10–4 mol dm−3 adenine, respectively. The es-biofilms hindered aggregation of Ag colloids more than Au but for both Au and Ag nanospheres the presence of es-biofilm reduced SERS signals through a combination of poorer aggregation and blocking of surface sites. For Ag, the effect of lower aggregation was to reduce the signals by a factor of ca. 2×, while site blocking gave a further 10× reduction for adenine. Similar results were found for Au nanospheres with adenine, although these particles gave low enhancement with pyocyanin. Nanostars were found to be unaffected by reduced aggregation and also showed lower site blocking effects, giving more reproducible signals than those from aggregated particles, which compensated for their lower enhancement factor. These results provide a rational basis for selecting enhancing substrates for use in in situ studies, where the further complexity means that it is important to begin with well-understood and controllable enhancing media. [ABSTRACT FROM AUTHOR]

Transition-metal-based metal–organic frameworks (MOFs) have received great interest for the development of low cost, platinum-free, non-precious water splitting electrocatalysts for hydrogen generation to resolve the energy crisis. Recent studies are mainly concerned with the use of MOFs as a self-sacrificing template for the synthesis of carbon-based electrocatalysts encapsulating metallic sites. However, the process often produces undesired metal nanoparticles, lowering the catalytic activity of the materials. This report explores a novel strategy to improve the intrinsic electrocatalytic activity of MOFs by a ligand substitution method. Ligands with different electron donating capacity have been used for the substitution process and the hydrogen evolution activity has been found to be greatly affected by the presence of different donor ligands. The MOF used in this work is designed with Ni as a metal center with 5-azido isophthalic acid as the primary linker. Subsequently, the MOF is functionalized with different organic moieties, i.e., N,N-dimethylethylenediamine (DMEDA) and 4-aminotetrafluoropyridine (4-ATFP) with rich non-metal catalytic active sites by means of post synthetic modification. A comparative study has been performed which shows the 4-ATFP functionalized MOF to have the best electrocatalytic activity among the three with significant performance in all three media, i.e. neutral, acidic and alkaline. Furthermore, theoretical approaches have been employed for the analysis of these experimental observations. [ABSTRACT FROM AUTHOR]

Enhancing the stability of metal nanoparticles is of great interest in the field of heterogeneous catalysis. An attractive prospect to this is the incorporation of metal nanoparticles into metal organic frameworks (MOFs) as it not only enhances the stability of metal nanoparticles but also influences their activity and selectivity. In the present study, we have prepared two magnetic silver catalysts (Ag@CuBTC-Fe3O4- PDA and Ag@Fe3O4-PDA) using two different supports to explore the effect of CuBTC on the catalytic activity of Ag nanoparticles. The catalytic activity of both catalysts was studied for the A3-coupling reaction and synthesis of benzopyranopyrimidines, wherein Ag@CuBTC-Fe3O4-PDA showed unexpectedly excellent catalytic performance. This excellent catalytic activity was attributed to the high surface area and nano-confinement effect provided by CuBTC which helps in the proper dispersion of silver nanoparticles and also helps in preventing their aggregation. Moreover, synergistic interaction between CuBTC and Ag nanoparticles in Ag@CuBTC-Fe3O4-PDA also plays an important role in the enhancement of the catalytic activity of Ag nanoparticles in comparison to Ag@Fe3O4-PDA. Furthermore, FT-IR, XRD, ICP-AES and XPS analysis of reused catalyst showed that the catalyst retains its structure, and chemical environment and can be reused up to six times. [ABSTRACT FROM AUTHOR]

While there are several metal nanocatalysts in hydrogenation reactions, the synthesis and research study of nano nickel are particularly intriguing due to this transition metal's magnetically separable nature. A novel approach for the massive production of nickel nanoparticles has been introduced by integrating a green medium into the conventional sol-gel auto combustion process (IN patent no. 360528). Lemon juice serves the purpose of the green medium, which acts as a solvent and reducing agent for the formation of nickel nanoparticles in solid form. The Ellingham diagram-based thermodynamics of metal oxide was attempted to explain the formation of metal nanoparticles over the metal oxide nanoparticles. X-ray diffraction analysis was used to optimise the reaction conditions for the formation of precise metal nanoparticles. The structure, morphology, and purity of the synthesised materials were investigated using a variety of state-of-the-art techniques. TEM analysis revealed a spherical morphology of nickel nanoparticles with an average particle size of 8.2 nm. Vibrating ample magnetometer data established the ferromagnetic character of the sample. Nanoparticles were found to be an effective catalyst for the reduction of p-nitrophenol and degradation of rhodamine with sodium borohydride acting as a reducing agent. This particular method of synthesis can pave the way for the solid-state production of crystalline nickel nanoparticles with excellent catalytic efficiency. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are potential templates for the synthesis of nanomaterials owing to the versatility of their structure. Most of the reported COFs comprise imine linkages. Herein, we report for the first time the synthesis of a urethane-linked COF (UCOF) using monoformylphloroglucinol and 1,4-phenylene diisocyanate as monomers. Furthermore, the UCOF was functionalized with cysteamine to introduce free dangling thiol groups into the cavity. The latter played a critical role in fixing the active metal efficiently and facilitating the confined growth of small metal nanoparticles (∼4–6 nm) with a high surface area leading to a pore-engineered heterogeneous Pd catalyst (PdNPs@UCOF-SH). The COF and Pd catalyst were characterized using various analytical techniques such as CP-MAS NMR, FTIR, PXRD, BET, FEG-SEM, HRTEM, XPS, TGA, and ICP-AES. The as-prepared UCOF-SH-supported Pd nanoparticles showed excellent catalytic activity in the Suzuki Miyaura cross-coupling reaction under mild conditions with low catalyst loading and eco-friendly solvents. The scope was extended to various aryl boronic acids and aryl halides (I, Br, and Cl). The halo-substituted and non-halo biaryl derivatives were obtained in good to excellent yields, within a shorter reaction time, avoiding the homocoupling of aryl boronic acid. The pore-engineered COF-derived catalyst is selective and easily recycled up to 10 runs without significant loss of catalytic activity. This reveals the robust nature of the PdNPs@UCOF-SH catalyst and the sustainability of the process which opens a new frontier for several catalytic applications. [ABSTRACT FROM AUTHOR]

Metal oxides have been considered as a promising anode material for lithium ion batteries (LIBs) due to their high theoretical capacities, low cost, natural abundance and environmental friendliness. However, the severe volume expansion upon cycling and poor conductivity limit their cycling stability and rate capability. To address this issue, Co3O4 and NiO nanoparticles encapsulated at the endpoints of nitrogen-doped carbon nanotube (NCNT) hybrids are designed and prepared by a metal catalyzed graphitization–nitridization driven tip-growth process and the subsequent oxidation in air, using (carbon nitride) C3N4 as a new solid-state carbon and nitrogen source. When used as an anode material for LIBs, the representative Co3O4@NCNT hybrid exhibits a high capacity of 1002 mA h g−1 at 100 mA g−1, an excellent rate capability of 673 mA h g−1 at 5.0 A g−1 and remarkable cycling stability of 837 mA h g−1 after 800 cycles at 1 A g−1, which are much superior to those of the Co3O4/CB control sample. The outstanding electrochemical performances of MxOy@NCNTs are due to their unique nanoarchitecture, which offers a porous conductive matrix for effective electron–ion transport and forms carbon nanocap confined MxOy nanoparticles as well as stress buffer nanocavities for robust structural stability during lithiation/delithiation processes. The results may pave a way for the rational structural design of high-performance metal oxide-based anode materials for next-generation LIBs. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) is an excellent lightweight electromagnetic shielding material with interesting features like flexibility and tuneable electrical conductivity. Moreover, it is corrosion-free, inexpensive and can be easily synthesized. Shielding by absorption, reflection or both can be realised in PANI depending on the requirements. An effective method to achieve very high attenuation is to form composites with materials such as graphene, metal nanoparticles and other high dielectric materials. However, most of the studies are based on shields of thickness ranging from a few hundred micrometres to millimetres. This work explores the EMI shielding properties of the composites of PANI with graphene in the S- and X-bands. Shielding effectiveness values as high as 57 dB are realised in these hybrid films of ∼10 μm thickness, rendering them suitable for lightweight and robust applications. It is found that the concentration of graphene in the PANI matrix significantly influences the shielding performance of these hybrid films and an optimum concentration of 2% graphene can make the absorption dominant shielding mechanism to be highly significant. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) for enhancing the signal intensity of laser-induced breakdown spectroscopy (LIBS) have received increasing attention in molecule spectroscopy. This study investigated the effect of gold nanoparticle concentration on the spectral emission of AlO molecular bands in nanoparticle-enhanced laser-induced Al plasmas using different concentrations (0–250 ng mL−1) of Au NPs deposited on the pure Al substrate surface. The spectral emission of AlO (0–0) and (1–1) increased and then dropped as the concentration of Au NPs increased from 0 ng mL−1 to 250 ng mL−1 and reached the strongest emission at 0.98 ng mL−1 concentration. In addition, the time-resolved characteristics of AlO spectra were also investigated, finding that the emission intensities and spectral lifetimes of AlO were different at different concentrations of Au NPs. The strongest peak intensity and longest spectral lifetime were observed at 0.98 ng mL−1 concentration. Finally, the vibration temperature of AlO was obtained, and its trend with the concentration of Au NPs was found to be consistent with the spectral emission. [ABSTRACT FROM AUTHOR]