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In this study, a straightforward, eco-friendly strategy for the phase modulation of MoS2 in 2D materials was developed for green-solvent-phase co-exfoliation and subsequent solvent-free drying/annealing processes, yielding binary-metal oxide nanoparticulate-decorated heterolayered 2D nanohybrids. As a green solvent, ethanol with poly(N-vinyl-2-pyrrolidone) provided an effective surface tension for liquid-phase exfoliation of the 2D materials (MoS2 and graphene). Electron injection of binary metal oxides (NiFe2O4) and graphene functional groups to the Mo 4d orbital played an important role in the modulating phase conversion of semiconductive MoS2 to metallic MoS2 in the nanohybrids. Moreover, the introduction of MoS2 and graphene tuned the diameter (∼6 nm) and effective crystalline domains of the NiFe2O4 nanoparticles in the resulting nanohybrid. The electrocatalytic activity of the nanohybrids exhibited outstanding performance in the hydrogen and oxygen evolution reactions due to the synergetic effects of the modified MoS2/graphene/NiFe2O4 components. Density functional theory calculations and the Tafel slope indicated that the combination of 1T-MoS2/graphene/NiFe2O4 nanohybrids achieved a lower activation barrier at the first hydrogen absorption step and the RDS for the interaction of adsorbed oxygen atoms with hydroxide in the hydrogen and oxygen evolution reactions. The nanohybrids were prepared as symmetric electrodes to assemble an environmentally-benign hydrogel cell for water-splitting systems, exhibiting excellent stability in deswelling–swelling cycles. We believe that the proposed process allows for phase-modulating 2D materials while alleviating the negative impact on the environment, creating desirable functionality for various catalytic applications. [ABSTRACT FROM AUTHOR]

Nanocrystals of Cs3Cu2I5, a metal halide with promising potential as a perovskite substitute, are successfully grown on graphene nanosheets. An intermediate stage of physically exfoliated graphene nanosheets, concurrent with the formation of copper‐based seeds on graphene surface, is developed, for the first time, allowing for the subsequent growth of Cs3Cu2I5 nanocrystals (CsNCs) to obtain CsNCs‐decorated graphene nanohybrids (CsGNHs). The morphology and properties of the CsGNHs depend on the input amount of graphene nanosheets during the reaction. The photoluminescence intensity of the CsGNHs decreases with increasing graphene content, indicating that graphene facilitates nonradiative energy transfer from the CsNCs in the CsGNHs. The inherent self‐trapping exciton emission of the CsNCs is also affected by the graphene substrate. As the graphene content increases, the emission peaks of the CsGNHs broaden and diminish. The CsGNHs emit a stable solid‐state luminescence with a large Stokes shift (zero self‐absorption) under a high‐energy ultraviolet (UV) light. Consequently, the CsGNHs can act as optoelectronic transducers and selectively generate a turn‐on photocurrent response under specific‐wavelength UV light. Additionally, a new anticounterfeiting strategy is developed using the CsGNHs as a luminescent black ink to fabricate luminescent quick‐response codes with fake pixels. [ABSTRACT FROM AUTHOR]

Isothiazolinones, which are widely used as chemical additives in many industries, may lead to skin irritation and allergies, thereby adversely influencing human health and the environment. Therefore, this paper proposes an efficient strategy for screening nanohybrid transducers to selectively detect 2-octyl-3-isothiazolinone (OIT) as a representative isothiazolinone. Chemical receptor (CR) candidates consisting of two parts: a reactive imidazole unit and side functional group for covalent conjugation with graphene and noncovalent interaction with the target, respectively, were designed. Five CR structures were selected and synthesized based on density-functional-theory calculations. The synthesized CRs were anchored to graphene for electrochemical transduction. The alkyl groups calculated to have the highest chemical affinities toward OIT were introduced in the CR/graphene nanohybrids (CGNHs). The electrochemical responses of the CGNHs toward OIT depended on the CR type, OIT concentration, and applied potential. Therefore, the combination of five CGNHs as a transducer with different potentials enabled the facile and effective detection of OIT (1–200 mg L–1) from the interferences through principal component analyses. The best CR corresponded to the dodecyloxy group, and the optimal measurement conditions included a scan rate of 25 mV s–1 and applied potentials of −0.75, 0.08, and 1.30 V (vs Ag/AgNO3). The proposed strategy can facilitate the efficient development of nanotransducers for identifying different types of chemical species such as biocides. [ABSTRACT FROM AUTHOR]

Research effort has increasingly been devoted to exploiting efficient noble-metal-free electrocatalysts because of their low cost and abundancy. Herein, metallic nanoparticulate-containing carbon nanofibers (MCNFs) featuring interior, nanoparticulate-in-pore structures were fabricated by taking advantage of cationic metal species/anionic surfactant complexes (MSCs). Binary MSC mixtures containing Fe–Co, Fe–Ni, and Co–Ni species were used to control not only the size/loading amount of the metallic phases but also the microstructural characteristics of the nanofiber matrices. Compared to their single MSC counterparts, the binary MSC mixtures allowed the generation of unique metallic phases, such as binary transition-metal oxides, and resulted in enhanced surface area/porosity and reduced charge transfer resistance. The noble-metal-free MCNFs were demonstrated as electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The MCNFs prepared using binary combinations of Fe–Ni and Co–Ni, viz., FeNiCNFs and CoNiCNFs, showed outstanding performances for the OER and HER, respectively. For the OER particularly, at potentials exceeding 1.6 V (vs RHE), the FeNiCNFs showed higher current densities than that of the well-known, conventionally used electrocatalyst RuO2. For overall water splitting, an asymmetric FeNiCNF∥CoNiCNF cell rendered performance stability that was 15% better than that of the RuO2∥Pt/C control cell. Based on the results of this study, various combinations of MSCs with controlled loading into functional matrices can be prepared to yield efficient, cost-effective electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

Improvements in Fenton reagents and processing systems are greatly desired. Here, we report the preparation of bifunctional iron/carbon nanofibers (ICNFs) with tailored microstructural characteristics for use as heterogeneous Fenton catalysts; these were constructed using binary/ternary polymer blends (polyacrylonitrile together with either/both poly-(methyl methacrylate) or/and poly-(N-vinyl-2-pyrrolidone)) and iron-(II) acetate as carbon and transition-metal precursors, respectively. The microphase separation of the different polymers containing the iron precursor was employed to control the (i) textural and electrical properties of the resulting carbon nanofibers and (ii) size and spatial distribution of the formed iron phases. Promising ICNFs with large effective surface areas and high porosities were successfully produced. Since the ICNF Fenton catalysts are also electrically conductive, a flow-controllable system with an integrated electrochemical three-electrode setup was also built, in which the ICNFs were employed as the sensing electrode for the electrochemical detection of dye influx. Amperometric monitoring of the flow system allowed the rapid detection of the dye influx introduced into the system, and then the Fenton reaction, coupled with a cathodic electrodeposition process, proceeded to degrade the dye. Further optimization of such systems employing ICNFs as the sensing electrode and Fenton catalyst will likely lead to cost-effective, energy-efficient water treatment processes. [ABSTRACT FROM AUTHOR]

Combining the characteristics of different materials offers exciting new opportunities for advanced applications in various fields. Herein, white light‐emitting diodes (WLEDs) with >200% reversible stretchability are fabricated using six‐color quantum dots (QDs) gel emitters. Stable aqueous‐phase alloy core/shell QDs with high quantum yield are obtained via ligand exchange using a ternary solvent system. Transparent and highly stretchable gels with large pores are created by binary‐solvent‐based gelation at low temperatures. Importantly, the QDs and the gel originate from the same two solvents, which make the QDs highly compatible with the gelation process. Consequently, QDs of six different colors are incorporated into the gel without any property degradation. The excellent optical properties of the QDs in the liquid phase (e.g., 17% higher photoluminescence (PL) intensity) are retained in the gel phase. The QD gel (QDG) exhibits elastic deformation up to 200%, with uniform PL over the entire gel. A down‐conversion WLED built using the QDG emitter produces cool white light with a color temperature of 6100 K, a color rendering index of 94, and a luminous efficacy of 72 lm W−1. In addition, the performance of the QDG‐based WLED remains unchanged even after more than 1000 bending/stretching cycles. [ABSTRACT FROM AUTHOR]

α,β-Unsaturated nitroolefins were reduced into nitroalkanes with a Hantzsch ester, promoted by S-benzyl isothiouronium iodide. The reactions proceeded successfully to afford the desired products in high yields and with excellent chemoselectivity. [ABSTRACT FROM AUTHOR]

The article reports on asymmetric aldol reaction catalyzed by L-Proline and Achiral Thiourea Fluoroboric Acid Salt. Topics discussed include the aldol reaction, challenges due to its stereoselectivity and proline. Additional topics discussed include major drawbacks of proline, alternatives and isothiouroniums to enhance the acidity of the NH moieties and allow more hydrogen bonding.

The article presents the process to accomplish the Asymmetric Aldol Reaction Catalyzed by L-Proline and Achiral Thiourea Fluoroboric Acid Salt and describes the chemical equations in this process.

Carbon nanotubes (CNTs), owing to their superior electrical and mechanical properties, are a promising alternative to nonmetallic electrically conducting materials. In practice, cellulose as a low-cost sustainable matrix has been used to prepare the aqueous dispersion of cellulose-CNT (C-CNT) nanocomposites. However, the compatibility with conventional solution-processing and structural rearrangement for improving conductivity has yet to be determined. Herein, a straightforward route to prepare a conductive composite material from single-walled CNTs (SWCNTs) and natural pulp is reported. High-power shaking realizes the self-alignment of individual SWCNTs in a cellulose matrix, resulting from the structural change in molecular orientations owing to countless collisions of zirconia beads in the aqueous mixture. The structural analysis of the dried C-CNT films confirms that the entanglement and dispersion of C-CNT nanowires determine the mechanical and electrical properties. Moreover, the rheological behavior of C-CNT inks explains their coating and printing characteristics. By controlling shaking time, the electrical conductivity of the C-CNT films with only 9 wt.% of SWCNTs from 0.9 to 102.4 S cm -1 are adjusted. the optimized C-CNT ink is highly compatible with the conventional coating and printing processes on diverse substrates, thus finding potential applications in eco-friendly, highly flexible, and stretchable electrodes is also demonstrated., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The functionalization of nanocarbon materials such as graphene has attracted considerable attention over the past decades. In this work, we designed and synthesized a unique N-heterocyclic carbene compound with a pyrene tail group (NHCp) to investigate how carbene species can be used for the functionalization of graphene. Although the carbene moiety of NHCp has the ability to covalently bond to graphene, the pyrene tail can noncovalently interact with graphene and allows monitoring its surrounding microenvironment. The major characteristics of the resulting nanohybrids were highly dependent on the type of graphene and the NHCp-to-graphene weight ratio. Importantly, despite the covalent functionalization of graphene, an anomalous decrease in the intensity of the Raman D peak and improved conductivity were observed for the nanohybrids. It was found that the covalent bond of NHCp to the graphene edge may allow the hybridization of their orbitals, which affects electronic energy levels and alters the double resonance process that originates the D peak at the edge defect. Importantly, the NHCp compound can act as a π acceptor (not just as a σ donor) via the NHCp-graphene covalent bridge. This is the first report showing that the concept of π-backdonation can be realized in two-dimensional materials, such as graphene, and rationally designed carbene molecules can functionalize graphene without losing their beneficial sp2 hybridization characteristics.