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Imogolite nanotubes (INTs) are predicted as a unique 1D material with spatial separation of conduction and valence band edges but their large band gaps have inhibited their use as photocatalysts. The first step toward using these NTs in photocatalysis and exploiting the polarization‐promoted charge separation across their walls is to reduce their band gap. Here, the modification of double‐walled aluminogermanate INTs by incorporation of titanium into the NT walls is explored. The precursor ratio x = [Ti]/([Ge]+[Ti]) is modulated between 0 and 1. Structural and optical properties are determined at different scales and the photocatalytic performance is evaluated for H2 production. Although the incorporation of Ti atoms into the structure remains limited, the optimal condition is found around x = 0.4 for which the resulting NTs reveal a remarkable hydrogen production of ≈1500 µmol g−1 after 5 h for a noble metal‐free photocatalyst, a 65‐fold increase relative to a commercial TiO2‐P25. This is correlated to a lowering of the recombination rate of photogenerated charge carriers for the most active structures. These results confirm the theoretical predictions regarding the potential of modified INTs as photoactive nanoreactors and pave the way for investigating and exploiting their polarization properties for energy applications. [ABSTRACT FROM AUTHOR]

The sky is the limit with regards to the societal impact nanomaterials can have on the lives. However, in this study, it is shown that their potential is out of this world. The planet Mars has an abundant source of calcium sulfate minerals and in this work, it is shown that these deposits can be the basis of transformative nanomaterials to potentially support future space endeavors. Vitally, the methods applied are low cost and require no specialized instruments of great expertise, strengthening the potential involvement of nanotechnology in sustaining Martian inhabitation. Through a scalable eco‐friendly liquid processing technique performed on two common terrestrial gypsum, this simple method presented a cost‐efficient procedure to yield suspensions of large aspect ratio anhydrite nanobelts with long‐term stability that are characterized through scanning electron microscopy and Raman spectroscopy. Transmission electron microscopy shows nanobelts to have a mesocrystal structure, with distinct nanoparticle constituents making up the lattice. Unexpectedly, anhydrite nanobelts have remarkable electronic properties, namely a bandgap that is easily tuned between semiconducting (≈2.2 eV) and insulating (≈4 eV) behaviors through dimensional control measured via atomic force microscopy. To demonstrate the application potential of the nanobelts; optoelectronic, electrochemical, and nanocomposite measurements are made. [ABSTRACT FROM AUTHOR]

The detection of the spread of toxic gas molecules in the air at low concentration in the field requires a robust miniaturized system combined with an analytical technique that is portable and able to detect and identify the molecules, as is the case with surface enhanced Raman scattering (SERS). This work aims to address capability gaps faced by first responders in real-time detection, identification and monitoring of neurotoxic gases by developing robust, reliable and reusable SERS microfluidic chips. Thus, the key performance attributes of a portable SERS detection system that must be addressed in detail are its limit of detection, response time and reusability. To this purpose, we integrate a 3D plasmonic architecture based on closely packed mesoporous silica (MCM48) nanospheres decorated with Au nanoparticle arrays, denoted as MCM48@Au, into a Si microfluidic chip designed and used for preconcentration and label-free detection of gases at a trace concentration level. The SERS performance of the plasmonic platform is thoroughly analyzed using DMMP as a model neurotoxic simulant over a 1 cm2 SERS active area and over a range of concentrations from 100 ppbV to 2.5 ppmV. The preconcentration-based SERS signal amplification by the mesoporous silica moieties is evaluated against dense silica counterparts, denoted as Stöber@Au. To assess the potential for applications in the field, the microfluidic SERS chip has been interrogated with a portable Raman spectrometer, evaluated with temporal and spatial resolution and subjected to several gas detection/regeneration cycles. The reusable SERS chip shows exceptional performance for the label-free monitoring of 2.5 ppmV gaseous DMMP. [ABSTRACT FROM AUTHOR]

Through a nucleophilic substitution reaction made on C60Br24 a new cyanofullerene derivative has been synthesized. The thermogravimetric analysis (TGA) has led to the following stoichiometry for the new compound: [C60(CN)7]–[Bu4N]+ which was further confirmed both with the X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR) and the electronic absorption spectroscopy. The thermal stability of [C60(CN)7]–[Bu4N]+ was studied very carefully by TGA-DTG, by differential scanning calorimetry (DSC) and by TGA-FTIR in comparison to the behavior of the reagents C60Br24 and tetrabutylammonium cyanide. [ABSTRACT FROM AUTHOR]

Covalent functionalization of tungsten disulfide (WS2) with photo‐ and electro‐active nickel‐porphyrin (NiP) is reported. Exfoliated WS2 interfacing NiP moieties with 1,2‐dithiolane linkages is assayed in the oxygen evolution reaction under both dark and illuminated conditions. The hybrid material presented, WS2−NiP, is fully characterized with complementary spectroscopic, microscopic, and thermal techniques. Standard yet advanced electrochemical techniques, such as linear sweep voltammetry, electrochemical impedance spectroscopy, and calculation of the electrochemically active surface area, are used to delineate the catalytic profile of WS2−NiP. In‐depth study of thin films with transient photocurrent and photovoltage response assays uncovers photo‐enhanced electrocatalytic behavior. The observed photo‐enhanced electrocatalytic activity of WS2−NiP is attributed to the presence of Ni centers coordinated and stabilized by the N4 motifs of tetrapyrrole rings at the tethered porphyrin derivative chains, which work as photoreceptors. This pioneering work opens wide routes for water oxidation, further contributing to the development of non‐noble metal electrocatalysts. [ABSTRACT FROM AUTHOR]

Morphological control at the nanoscale paves the way to fabricate nanostructures with desired plasmonic properties. In this study, we discuss the nanoengineering of plasmon resonances in 1D hollow nanostructures of two different AuAg nanotubes, including completely hollow nanotubes and hybrid nanotubes with solid Ag and hollow AuAg segments. Spatially resolved plasmon mapping by electron energy loss spectroscopy (EELS) revealed the presence of high order resonator-like modes and localized surface plasmon resonance (LSPR) modes in both nanotubes. The experimental findings accurately correlated with the boundary element method (BEM) simulations. Both experiments and simulations revealed that the plasmon resonances are intensely present inside the nanotubes due to plasmon hybridization. Based on the experimental and simulated results, we show that the novel hybrid AuAg nanotubes possess two significant coexisting features: (i) LSPRs are distinctively generated from the hollow and solid parts of the hybrid AuAg nanotube, which creates a way to control a broad range of plasmon resonances with one single nanostructure, and (ii) the periodicity of the high-order modes are disrupted due to the plasmon hybridization by the interaction of solid and hollow parts, resulting in an asymmetrical plasmon distribution in 1D nanostructures. The asymmetry could be modulated/engineered to control the coded plasmonic nanotubes. [ABSTRACT FROM AUTHOR]

Easy and effective modification approaches for transition metal dichalcogenides are highly desired in order to make them active toward electrocatalysis. In this manner, we report functionalized molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) via metal-ligand coordination with pyridine rings for the subsequent covalent grafting of a cobalt-porphyrin. The new hybrid materials were tested towards an electrocatalytic hydrogen evolution reaction in both acidic and alkaline media and showed enhanced activity compared to intact MoSe2 and WSe2. Hybrids exhibited lower overpotential, easier reaction kinetics, higher conductivity, and excellent stability after 10,000 ongoing cycles in acidic and alkaline electrolytes compared to MoSe2 and WSe2. Markedly, MoSe2-based hybrid material showed the best performance and marked a significantly low onset potential of −0.17 V vs RHE for acidic hydrogen evolution reaction. All in all, the ease and fast modification route provides a versatile functionalization procedure, extendable to other transition metal dichalcogenides, and can open new pathways for the realization of functional nanomaterials suitable in electrocatalysis. [ABSTRACT FROM AUTHOR]

In the present work, some MoS2 and WS2 nanosheets were prepared and characterized. Depending on the preparation procedures, trigonal prismatic (2H) or octahedral (1T) coordination of the metal atoms was obtained, exhibiting metallic (1T) or semiconducting (2H) character. Both MoS2 and WS2 nanosheets were found exhibiting large nonlinear optical (NLO) responses, strongly dependent on their metallic (1T) or semiconducting (2H) character. Therefore, the semiconducting character of MoS2 and WS2 exhibits positive nonlinear absorption and strong self-focusing behavior, while their metallic character counterparts exhibit strong negative nonlinear absorption and important self-defocusing behavior. In addition, the semiconducting MoS2 and WS2 were found exhibiting important and very broadband optical limiting (OL) action extending from 450 to 1750 nm. Therefore, by selecting the crystalline phase of the nanosheets, that is, their semiconduction/metallic character, their NLO response can be greatly modulated. The results of the present work demonstrate unambiguously that the control of the crystalline phase of MoS2 and WS2 provides an efficient strategy for 2D nanostructures with custom-made NLO properties for specific optoelectronic and photonic applications such as OL, saturable absorption, and optical switching. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4), possessing high thermal and chemical stability, non-toxicity, facile synthesis, and low band gap energy is a promising candidate for photocatalytic applications. In this study, bulk and exfoliated g-C3N4 were synthesised from different precursors (melamine and urea). Moreover, the surface of bulk g-C3N4 and exfoliated g-C3N4 was modified with graphene (0.5 wt% and 1 wt%) aiming to obtain a prolonged carrier lifetime. The effect of g-C3N4 synthesis from various precursors and the influence of graphene content on the photocatalytic activity during the degradation of a water–methanol mixture under UVC irradiation were examined, in comparison to commercial P25. Hydrogen, methane and carbon monoxide were the decomposition products; hydrogen was the main product of decomposition, whereas CH4 and CO resulting from the reduction of CO2 were generated in a significantly smaller amount. All the produced photocatalysts, whether pure or modified with graphene, exhibited higher activity than the commercial photocatalyst P25. [ABSTRACT FROM AUTHOR]

Explosive percolation is an experimentally-elusive phenomenon where network connectivity coincides with onset of an additional modification of the system; materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Nanocomposites present a structurally- and chemically-varied playground to realise explosive percolation in practically-applicable systems but this is yet to be exploited by design. Herein, we demonstrate composites of graphene oxide and synthetic polymer latex which form segregated networks, leading to low percolation threshold and localisation of conductive pathways. In situ reduction of the graphene oxide at temperatures of <150 °C drives chemical modification of the polymer matrix to produce species with phenolic groups, which are known crosslinking agents. This leads to conductivities exceeding those of dense-packed networks of reduced graphene oxide, illustrating the potential of explosive percolation by design to realise low-loading composites with dramatically-enhanced electrical transport properties. Materials with correlated localisation of percolating particles and emergent conductive paths can realise sharp transitions and high conductivities characteristic of the explosively-grown network. Here the authors exploit explosive percolation to realize a low-loading composite material with enhanced electrical properties by in-situ reduction of graphene oxide. [ABSTRACT FROM AUTHOR]

The control of magnetization inversion dynamics is one of the main challenges driving the design of new nanostructured magnetic materials for magnetoelectronic applications. Nanoparticles with an onion-like architecture offer a unique opportunity to expand the possibilities of combining different phases at the nanoscale and also modulating the coupling between magnetic phases by introducing spacers into the same structure. Here, we report the fabrication, by a three-step high temperature decomposition method, of Fe3O4/MgO/CoFe2O4 onion-like nanoparticles and their detailed structural analysis, elemental compositional maps and magnetic response. The core/shell/shell nanoparticles present epitaxial growth and cubic shape with an overall size of (29 ± 6) nm. These nanoparticles consist of a cubic iron oxide core of 22 ± 4nm in size covered by two shells, the inner of magnesium oxide and the outer of cobalt ferrite of thicknesses ∼1 and ∼2.5 nm, respectively. The magnetization measurements show a single reversion magnetization curve and the enhancement of the coercivity field, from HC ∼ 608 Oe for the Fe3O4/MgO to HC ∼ 5890 Oe for the Fe3O4/MgO/CoFe2O4 nanoparticles at T = 5 K, ascribed to the coupling between both ferrimagnetic phases with a coupling constant of Jc = 2 erg cm−2. The system also exhibits an exchange bias effect, where the exchange bias field increases up to HEB ∼ 2850 Oe at 5 K accompanied by the broadening of the magnetization loop of HC ∼ 6650 Oe. This exchange bias effect originates from the freezing of the surface spins below the freezing temperature TF = 32 K that pinned the magnetic moment of the cobalt ferrite shell. [ABSTRACT FROM AUTHOR]

High aspect-ratio gold nanostructures sustain Fabry–Perot-like surface plasmon responses from infrared to visible light energies. We show that some resonances can be tuned by means of laser irradiation, where low energy modes stay unperturbed. After laser irradiation, gold nanowires' tips are transformed into nanoparticles of various sizes joint to gold nanowires, producing high aspect-ratio half-dumbbells and dumbbells structures. The plasmonic behaviour of both the nanowires and the newly created nanostructures has been characterised by in-depth monochromated electron energy loss spectroscopy (EELS) developed in a transmission electron microscope (TEM) and state-of-the-art discrete dipole approximation (DDA) calculations. All these analyses serve as experimental proof of the selective tuning (or robustness) of the plasmonic modes of the nanostructures in a specific spectral range, which is of critical interest regarding applications for sensing devices, nano-sources or nanophotonic waveguide, as well as optical remote control. [ABSTRACT FROM AUTHOR]

While cobaloximes have been protagonists in the molecular (photo)catalytic hydrogen evolution reaction field, researchers originally shed light on the catalytically active metallic center. However, the specific chemical environment of cobalt, including equatorial and axial ligation, has also a strong impact on the catalytic reaction. In this article, we aim to demonstrate how pyridine vs. imidazole axial ligation of a cobaloxime complex covalently grafted on graphene affects the hydrogen evolution reaction performance in realistic acidic conditions. While pyridine axial ligation mirrors a drastically superior electrocatalytic performance, imidazole exhibits a remarkable long-term stability. [ABSTRACT FROM AUTHOR]

Development of graphene/perovskite heterostructures mediated by polymeric materials may constitute a robust strategy to resolve the environmental instability of metal halide perovskites and provide barrierless charge transport. Herein, a straightforward approach for the growth of perovskite nano-crystals and their electronic communication with graphene is presented. Methylammonium lead bromide (CH3NH3PbBr3) nano-crystals were grown in a poly[styrene-co-(2-(dimethylamino)ethyl methacrylate)], P[St-co-DMAEMA], bi-functional random co-polymer matrix and non-covalently immobilized on graphene. P[St-co-DMAEMA] was selected as a bi-modal polymer capable to stabilize the perovskite nano-crystals via electrostatic interactions between the tri-alkylamine amine sites of the co-polymer and the A-site vacancies of the perovskite and simultaneously enable Van der Waals attractive interactions between the aromatic arene sites of the co-polymer and the surface of graphene. The newly synthesized CH3NH3PbBr3/co-polymer and graphene/CH3NH3PbBr3/co-polymer ensembles were formed by physical mixing of the components in organic media at room temperature. Complementary characterization by dynamic light scattering, microscopy, and energy-dispersive X-ray spectroscopy revealed the formation of uniform spherical perovskite nano-crystals immobilized on the graphene nano-sheets. Complementary photophysical characterization by UV-Vis absorption, steady-state, and time-resolved fluorescence spectroscopy unveiled the photophysical properties of the CH3NH3PbBr3/co-polymer colloid perovskite solution and verified the electronic communication within the graphene/CH3NH3PbBr3/co-polymer ensembles at the ground and excited states. [ABSTRACT FROM AUTHOR]

MoS2 has been explored as a potential material for hydrogen evolution reaction (HER) and lithium‐ion batteries (LIBs). However, the limited number of active sites and poor conductivity restrain its applications. Herein, a facile method is reported to construct MoS2 nanosheets (MoS2 NSs) grown on agar‐derived 3D nitrogen‐doped porous carbon (MoS2‐NPC). The as‐prepared MoS2‐NPC composite exhibits good stability and HER electrocatalytic properties with a low overpotential of 209 mV at 10 mA cm−2 and a small Tafel slope of 41 mV dec−1. Furthermore, as an anode of LIBs, it delivers an initial discharge capacity of 1289 mAh g−1 at 0.1 A g−1 and rate capability of 712 and 419 mAh g−1 at 0.5 and 2.0 A g−1, respectively. This is attributed to the synergistic effects and unique 3D network structure, which avoids the aggregation of MoS2 and results in more exposed active sites. The agar‐derived 3D nitrogen‐doped porous carbon can act as a support material for MoS2 NSs dispersed on the surface, providing a cheap and efficient strategy to prepare high quality catalysts for electrochemical energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

The incorporation of plasmonic nanoconstructs in biodegradable polymeric nanoparticles (NPs), together with therapeutic drugs in a controlled procedure is of interest for different applications in Nanomedicine. Advanced hybrid nanomaterials can be engineered by combining the in situ formation of plasmonic palladium nanosheets (NSs) and the proper ionic nature of the encapsulated drug. This study presents a new procedure to synthesize hybrid nanostructures by a Pickering double emulsion. Anisotropic palladium (Pd) NSs with unique near‐infrared (NIR)‐optical properties can be assembled within a poly lactic‐co‐glycolic acid matrix of < 200 nm NPs, when Pd precursors are in situ reduced via a gas‐phase procedure. The hybrid nanomaterials respond to external NIR light stimulus. The unprecedented precision to assemble, in a single stage, plasmonic nanoconstructs having a total loading selectivity, when encapsulated in combination with hydrophobic drugs, offers new opportunities in the new class of theragnostics, in particular when triggered drug delivery and photothermal therapies are required. [ABSTRACT FROM AUTHOR]

The covalent functionalization of chemically exfoliated molybdenum disulfide (ce-MoS2) with hydrophobic poly(methyl methacrylate) and hydrophilic poly(acrylic acid) polymers, in a single-step without additives, is presented. The nature of chemical modification and the impact on the structure of ce-MoS2 were spectroscopically investigated. Complexation of Eu3+ was accomplished on grafted polycarboxylate chains on MoS2. [ABSTRACT FROM AUTHOR]

Ruddlesden‐Popper lead halide perovskite (RP‐LHP) nano‐nanostructures can be regarded as self‐assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a single or a few (n=2‐4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimension. Here, the preparation of highly (photo)chemical and colloidal stable hybrid LHP nanosheets (NSs) of ca. 7.4 μm lateral size and 2.5 nm quantum well height (thereby presenting a deep blue emission at ca. 440 nm), is reported for the first time. The NSs are close‐lying and they even interconnect when deposited on a substrate. Their synthesis is based on the use of the p‐toluenesulfonic acid/dodecylamine (pTS/DDA) ligand pair and their (photo)chemical stability and photoluminescence is enhanced by adding EuBr2 nanodots (EuNDs). Strikingly, they can be preserved as a solid and stored for at least one year. The blue emissive colloid can be recovered from the solid as needed by simply dispersing the powder in toluene and then using it to prepare solid films, making them very promising candidates for manufacturing devices. [ABSTRACT FROM AUTHOR]

Ruddlesden‐Popper lead halide perovskite (RP‐LHP) nano‐nanostructures can be regarded as self‐assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a single or a few (n=2‐4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimension. Here, the preparation of highly (photo)chemical and colloidal stable hybrid LHP nanosheets (NSs) of ca. 7.4 μm lateral size and 2.5 nm quantum well height (thereby presenting a deep blue emission at ca. 440 nm), is reported for the first time. The NSs are close‐lying and they even interconnect when deposited on a substrate. Their synthesis is based on the use of the p‐toluenesulfonic acid/dodecylamine (pTS/DDA) ligand pair and their (photo)chemical stability and photoluminescence is enhanced by adding EuBr2 nanodots (EuNDs). Strikingly, they can be preserved as a solid and stored for at least one year. The blue emissive colloid can be recovered from the solid as needed by simply dispersing the powder in toluene and then using it to prepare solid films, making them very promising candidates for manufacturing devices. [ABSTRACT FROM AUTHOR]

Zinc indium sulfide belongs to the family of layered ternary chalcogenides. Although ZnIn2S4 has a suitable bandgap in the visible range, its optoelectronic properties are not fully investigated. Most photodetectors based on layered semiconductors suffer from large dark currents, which hamper their performance and energy efficiency. In this work, high quality ZnIn2S4 single crystals are synthesized via chemical vapor transport. The free‐standing crystals are ≈20 μm thick and up to 2 cm2 in area and produce large photocurrents upon UV–vis illumination, while also maintaining extremely low currents in the dark. This allows to fabricate a simple photodetector with ohmic contacts, exhibiting extremely small dark currents down to 10–12 A. The ON/OFF (light/dark) switching ratio reaches value of 106, the highest reported for a layered semiconductor. Furthermore, the photodetector exhibits remarkable responsivity of 173 A W–1 and excellent detectivity of 1.7 × 1012 Jones. To demonstrate sensitivity and flexibility of the ZnIn2S4 crystals, a wearable device is also fabricated. The wearable is able to record human heart rate and compare it with signal measured by a commercial smartwatch. The results suggest a substantial research potential in further explorations of ZnIn2S4 and other ternary chalcogenides for optoelectronic applications. [ABSTRACT FROM AUTHOR]

The realization of novel heterostructures arising from the combination of nanomaterials is an effective way to modify their physicochemical and electrocatalytic properties, giving them enhanced characteristics stemming from their individual constituents. Interfacing carbon nanohorns (CNHs) possessing high porosity, large specific surface area, and good electrical conductivity, with MoS2 owning multiple electrocatalytic active sites but lacking significant conductivity, robust interactions, and effective structure, can be a strategy to boost the electrocatalytic reduction of protons to molecular hydrogen. Herein, in a stepwise approach, complementary functional groups are covalently introduced at the conical tips and sidewalls of CNHs, along with the basal plane of MoS2, en route the construction of 3D‐2D CNH‐MoS2 heterostructures. The increased MoS2 loading onto CNHs, improving and facilitating charge delocalization and transfer in neighboring CNHs, along with the plethora of active sites, results in excellent electrocatalytic activity for protons reduction, same as that of commercial Pt/C. Minute overpotential is registered, low Tafel slope and small charge‐transfer resistance for electrocatalyzing the evolution of hydrogen from the newly prepared heterostructure of 0.029 V, 71 mV dec−1, and 34.5 Ω, respectively. Furthermore, the stability of the 3D‐2D CNH‐MoS2 heterostructure is validated after performing 10 000 ongoing electrocatalytic cycles. [ABSTRACT FROM AUTHOR]

The NASICON superionic solid electrolyte Li1+xAlxTi2-x(PO4)3 (LATP) with 0.3 ≤ x ≤ 0.5 remains one of the most promising solid electrolytes thanks to its good ionic conductivity and outstanding stability in ambient air. Despite the intensive research for bulk systems, there are only very few studies of LATP in a thin film form (thickness < 1 mm) and its implementation in all-solid-state batteries and microbatteries. The following study fills this gap by exploring the properties of high performance LATP thin films fabricated by large-area Pulsed Laser Deposition (PLD). The as-deposited thin films exhibit an ionic conductivity of around 0.5 µS cm-1 at room temperature (comparable to the state-of-the-art of LiPON) which increases to a remarkably high value of 0.1 mS cm-1 after an additional annealing at 800 °C. A possible cause for this significant enhancement in ionic conductivity by two orders of magnitude is the formation of a glassy, intergranular phase. The performance of both as-deposited and annealed LATP films makes them suitable as solid electrolytes, which opens the path to a new family of stable and high performance all-solid-state thin film batteries. [ABSTRACT FROM AUTHOR]

In this work, we fabricated quantum dot light-emitting diodes using solution-processed NiO as the hole injection layer to replace the commonly used poly(3,4-ethylenedioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS) layer. We successfully prepared NiO films by spin coating the NiO precursor, then annealing them, and then treating them with UV-ozone under optimized conditions. The best device with the NiO film shows higher current efficiency (25.1 cd/A) than that with the PEDOT:PSS layer (22.3 cd/A). Moreover, the long-term stability of the devices with NiO which is annealed at 500 °C is improved substantially. These results suggest that the NiO layer can be a good alternative for developing stable devices. [ABSTRACT FROM AUTHOR]

The preparation of an MoS2–polymer carbon nanodot (MoS2‐PCND) hybrid material was accomplished by employing an easy and fast bottom‐up synthetic approach. Specifically, MoS2‐PCND was realized by the thermal decomposition of ammonium tetrathiomolybdate and the in situ complexation of Mo with carboxylic acid units present on the surface of PCNDs. The newly prepared hybrid material was comprehensively characterized by spectroscopy, thermal means, and electron microscopy. The electrocatalytic activity of MoS2‐PCND was examined in the hydrogen evolution reaction (HER) and compared with that of the corresponding hybrid material prepared by a top‐down approach, namely MoS2‐PCND(exf‐fun), in which MoS2 was firstly exfoliated and then covalently functionalized with PCNDs. The MoS2‐PCND hybrid material showed superior electrocatalytic activity toward the HER with low Tafel slope, excellent electrocatalytic stability, and an onset potential of −0.16 V versus RHE. The superior catalytic performance of MoS2‐PCND was rationalized by considering the catalytically active sites of MoS2, the effective charge/energy‐transfer phenomena from PCNDs to MoS2, and the synergetic effect between MoS2 and PCNDs in the hybrid material. [ABSTRACT FROM AUTHOR]

Realizing the full potential of oxide‐supported single‐atom metal catalysts (SACs) is key to successfully bridge the gap between the fields of homogeneous and heterogeneous catalysis. Here we show that the one‐pot combination of Ru1/CeO2 and Rh1/CeO2 SACs enables a highly selective olefin isomerization‐hydrosilylation tandem process, hitherto restricted to molecular catalysts in solution. Individually, monoatomic Ru and Rh sites show a remarkable reaction specificity for olefin double‐bond migration and anti‐Markovnikov α‐olefin hydrosilylation, respectively. First‐principles DFT calculations ascribe such selectivity to differences in the binding strength of the olefin substrate to the monoatomic metal centers. The single‐pot cooperation of the two SACs allows the production of terminal organosilane compounds with high regio‐selectivity (>95 %) even from industrially‐relevant complex mixtures of terminal and internal olefins, alongside a straightforward catalyst recycling and reuse. These results demonstrate the significance of oxide‐supported single‐atom metal catalysts in tandem catalytic reactions, which are central for the intensification of chemical processes. [ABSTRACT FROM AUTHOR]

Realizing the full potential of oxide‐supported single‐atom metal catalysts (SACs) is key to successfully bridge the gap between the fields of homogeneous and heterogeneous catalysis. Here we show that the one‐pot combination of Ru1/CeO2 and Rh1/CeO2 SACs enables a highly selective olefin isomerization‐hydrosilylation tandem process, hitherto restricted to molecular catalysts in solution. Individually, monoatomic Ru and Rh sites show a remarkable reaction specificity for olefin double‐bond migration and anti‐Markovnikov α‐olefin hydrosilylation, respectively. First‐principles DFT calculations ascribe such selectivity to differences in the binding strength of the olefin substrate to the monoatomic metal centers. The single‐pot cooperation of the two SACs allows the production of terminal organosilane compounds with high regio‐selectivity (>95 %) even from industrially‐relevant complex mixtures of terminal and internal olefins, alongside a straightforward catalyst recycling and reuse. These results demonstrate the significance of oxide‐supported single‐atom metal catalysts in tandem catalytic reactions, which are central for the intensification of chemical processes. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide nanosheets covalently modified with porphyrin were prepared and fully characterized. Neither the porphyrin absorption nor its fluorescence was notably affected by covalent linkage to MoS2. The use of transient absorption spectroscopy showed that a complex ping‐pong energy‐transfer mechanism, namely from the porphyrin to MoS2 and back to the porphyrin, operated. This study reveals the potential of transition‐metal dichalcogenides in photosensitization processes. [ABSTRACT FROM AUTHOR]

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Over the last decades, there has been considerable interest in the synthesis of one-dimensional (1D) metal oxide nanostructures that can be used in gas sensor devices. Heterostructures, obtained by a combination of different semiconductor nanomaterials with different band energies, have been extensively studied in order to enhance their gas-sensing performance. In this context, our present study focuses on the investigation of chemiresistive- sensing capabilities of a combination of TiO2 nanoparticles and V2O5 nanowires obtained via hydrothermal treatment of the peroxo- metal complex. The formation of V2O5/TiO2 heterostructures was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. This study also proposes an efficient approach to produce 1D V2O5/TiO2 heterostructures with a good range of detection (0.09-1.25 ppm) and remarkable ozone-sensing properties related to repeatability and selectivity. [ABSTRACT FROM AUTHOR]

In this work, we will report the generation of Au clusters in a purely siliceous MCM-22 zeolite. The catalytic properties of these Au clusters have been tested for the selective oxidation of cyclohexane to cyclohexanol and cyclohexanone (KA-oil). The Au clusters encapsulated in the MCM-22 zeolite are highly active and selective for the oxidation of cyclohexane to KA-oil, which is superior to Au nanoparticles on the same support. These results suggest that Au clusters are highly active for the activation of oxygen to produce radical species. [ABSTRACT FROM AUTHOR]

A new Ag@m-Ag2Mo2O7 plasmonic hybrid nanostructure was designed by an easy two-step synthesis method. Firstly, very thin photosensitive monoclinic m-Ag2Mo2O7 nanowires (NWs) were synthesized under ambient pressure and at low temperature by using Ag2Mo3O10·2H2O NWs as a pre-nanostucturated starting material. This innovative soft chemistry route offers some precise control over the purity, the structure and the nanostructuration of the m-Ag2Mo2O7 NWs that exhibit a very thin diameter of around 100 nm and a superior specific surface area compared to previously reported synthesis methods. Secondly, the plasmonic hybrid nanostructure Ag@m-Ag2Mo2O7 was easily in situ obtained via an all solid-state photodeposition method, by irradiating the m-Ag2Mo2O7 NWs under low energy and low-power UV-light. The composition, morphology and plasmonic properties of the nanocomposite were investigated by a combination of energy-dispersive X-ray spectroscopy, high-resolution scanning transmission electron microscopy, X-ray photoelectron spectroscopy and Auger spectroscopy, and near-infrared, Raman and UV-vis spectroscopies as well as spatially-resolved electron energy-loss spectroscopy. A plausible mechanism explaining the formation of the nano-heterostructure under irradiation was also discussed. The Ag@m-Ag2Mo2O7 nanostructure manifests interesting plasmonic properties particularly high surface-enhanced Raman scattering (SERS) sensitivity probed using 2,2′-bipyridine. [ABSTRACT FROM AUTHOR]