Search

A typical synthesis of the FeN4X-SAzyme (x = F, Cl, Br, I) is based on high-temperature pyrolysis. The results showed that the chlorine-coordinated monatomic iron material (FeN4Cl-SAzyme) was a promising catalyst for the oxygen reduction reaction.

The first germanimidoyl chloride was synthesized, which could be facilely functionalised to yield a germanimine or an amide lithium salt.

In this study, we have creatively designed photoanode and counter electrodes materials with blueberries as the key performance improvement, and verified the contribution of blueberry to the photoelectric conversion performance of DSSCs.

This feature article reviews the recent advancements in the synthesis and applications of amorphous/crystalline heterophase electrocatalysts.

An electrochemical immunoassay was designed based on an atomically Ru-dispersed nitrogen-doped carbon modified disposable SPCE for sensitive and specific screening of low-abundance influenza A (H1N1) virus with an innovative split-type strategy.

A combined study on the anti-sintering ability, SO2-poisoning mechanism and thermal regeneration property of CeWSnOx catalysts for NH3-SCR reaction.

A self-assembled two-dimensional montmorillonite nanocoating enables significantly enhanced corona resistance in the Kapton film.

In this study, a facile and cost-effective PbO2 layer coated TiO2 nanotubes (NTs) electrode was fabricated to serve as an anode to degrade a model contaminant under the condition of high sulfate concentration.

The different metabolome responses of MSSA and MRSA to antibiotics provide us with new insights into how S. aureus develops antibiotic resistance.

Herein, we describe a palladium/norbornene-catalyzed trifunctionalization of ortho-unsubstituted aryl iodides via a highly chemoselective cascade process involving intermolecular ortho acylation/intramolecular ortho alkylation/ipso alkenylation.

A magic liquid is a material whose transmittance and structural color can be dynamically modulated upon flowing. This study opens a novel type of responsive smart optical materials with potential new applications in diverse areas.

A chemo- and regioselective Pd(0)-catalyzed spiroannulation has been successfully developed. The key feature of this method is the use of readily available 1,2-dihaloarenes, alkynes and 2-naphthols for the rapid assembly of spirocarbocyclic molecules. Mechanistic studies revealed that this domino reaction proceeded through a cascade of oxidative addition to Pd(0), alkyne migratory insertion, and 2-naphthol-facilitated dearomatizing [4+1] spiroannulation.

The isolable anionic oxoborane 3 and thioxoborane 4 have been assembled using a 1,2-bis(imino)acenaphthene ligand (Dip-BIAN). Structural characterization and DFT calculations confirmed that two compounds contain terminal doubly bonded B[double bond, length as m-dash]E (E = O, S) groups, respectively, in which only the B[double bond, length as m-dash]O group is associated with imidazolium via a hydrogen bond.

Photonic crystal supraparticles (PCSs) obtained by self-assembly of colloidal building blocks hold promise for applications in various areas. The majority of PCSs are based on isotropic colloidal spheres, fundamentally limiting their structural and functional diversity. Herein we demonstrate the magnetic assembly of Janus PCSs with increased complexity from a colloidal mixture of nonmagnetic spheres and magnetic ellipsoids. The key to this strategy is the use of non-uniform magnetic fields to simultaneously induce the phase separation of binary particles and assist the subsequent crystallization of anisotropic magnetic ellipsoids. Due to their different crystalline structures, the nonmagnetic and magnetic regions of Janus PCSs exhibit isotropic and anisotropic optical properties, respectively. Moreover, the structural colour can be tuned by magnetically controlling the orientation of supraparticles. Our study not only produces multi-functional PCSs with novel structures and properties but also provides a new model system for understanding the colloidal assembly of binary mixtures.

Porphyrin-based photocatalytic oxygen evolution (POE) has exhibited great potential in artificial photosynthesis; however, a few reports exist on efficient nanocatalytic systems due to the fast photoinduced charge recombination. Here, cobalt(III) tetraphenylporphyrin (CoP) nanowires (NWs) are first synthesized at a large-scale via a simple chemical reaction, and transformed in situ into zero-dimensional CoP/NGQDs nanocomposites by adding nitrogen-doped graphene quantum dots (NGQDs) as the template and dopant. Under the visible light irradiation, no detectable POE activity of CoP NWs is observed in an acid heterogeneous system, while the currently highest POE rate on the molecule (350 μmol g−1 h−1) is achieved with CoP/NGQDs as the photocatalyst. Systematic experiments reveal that the NGQDs-limiting self-assembly of CoP molecules along the axial direction and subsequent formation of Z-scheme CoP/NGQDs heterojunctions are crucial for efficient POE. The nanostructures lead to enough exposure of the central Co atom as POE active sites and longer recombination lifetime of the photoinduced charge in CoP/NGQDs (87.8 ps) than that in CoP NWs (32.2 ps) due to the generation of (CoP+·NGQDs−)* exciplex. This work provides a new strategy to use a nature-like semiconductor molecule as a direct catalyst for artificial photosynthesis.

Halide perovskites are widely used as an absorbing or emitting layer in emerging high-performance optoelectronic devices due to their high absorption coefficients, long charge carrier diffusion lengths, low defect density and intense photoluminescence. Si-based materials (c-Si, a-Si, SixNy, SiCx and SiO2) play important roles in high performance perovskite optoelectronic devices due to the dominance of Si-based microelectronics and the important role of Si-based solar cells in photovoltaics. Controlling the preparation of perovskite materials on the dominant Si optoelectronics platform is a crucial step to realize practical perovskite-based optoelectronic devices. This review highlights the recent progress in Si-based perovskite optoelectronic devices including perovskite/Si tandem solar cells, perovskite/Si photodetectors, perovskite/Si light emitting diodes and optically pumped lasers. The remaining challenge in Si-based perovskite optoelectronic devices research are discussed.

A Ni-based metal organic framework (Ni-BDC) and subsequently derived NiFe-LDH were studied to overcome the defect of the low availability of active sites for the oxygen evolution reaction (OER) during the water splitting process. This work reported NiFe-LDH nanosheets with an ultra-thin structure through an in situ surface-conversion derived from Ni-BDC. The unique structure and characteristic morphology were confirmed using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy, and the OER activities of the catalysts were systematically studied. The obtained results indicated that the synthesized Ni-BDC@NiFe-LDH-2 showed excellent OER activity, with a low overpotential of 272 mV at a current density of 10 mA cm−2, a small Tafel slope of 45 mV dec−1, and excellent stability, owing to the addition of abundant metal sites and the expansion of the electron transport channels during the conversion process to form the ultra-thin layer structure. This work provides a novel strategy for the application, design, and manufacture of metal organic framework (MOF)-based high-efficiency active materials.

Dithiophosphinic acids (DPAHs, expressed as R1R2PSSH) are a type of sulfur-donor ligand that have been vastly applied in hydrometallurgy. In particular, DPAHs have shown great potential in highly efficient trivalent actinide/lanthanide separation, which is one of the most challenging tasks in separation science and is of great importance for the development of an advanced fuel cycle in nuclear industry. However, DPAHs have been found liable to undergo oxidative degradation in the air, leading to significant reduction in the selectivity of actinide/lanthanide separation. In this work, the atmospheric degradation of five representative DPAH ligands was investigated for the first time over a sufficiently long period (180 days). The oxidative degradation process of DPAHs elucidated by ESI-MS, 31P NMR, and FT-IR analyses is R1R2PSSH → R1R2PSOH → R1R2POOH → R1R2POO–OOPR1R2, R1R2PSSH → R1R2PSS–SSPR1R2, and R1R2PSSH → R1R2PSOH → R1R2POS–SOPR1R2. Meanwhile, the determination of pKa values through pH titration and oxidation product by PXRD further confirms the S → O transformation in the process of DPAH deterioration. DFT calculations suggest that the hydroxyl radical plays the dominant role in the oxidation process of DPAHs and the order in which the oxidation products formed is closely related to the reaction energy barrier. Moreover, nickel salts of DPAHs have shown much higher chemical stability than DPAHs, which was also elaborated through molecular orbital (MO) and adaptive natural density portioning (AdNDP) analyses. This work unambiguously reveals the atmospheric degradation mechanism of DPAHs through both experimental and theoretical approaches. At the application level, the results not only provide an effective way to preserve DPAHs but could also guide the design of more stable sulfur-donor ligands in the future.

Developing effective carbon materials for post-combustion CO2 capture (PCC) has received great attentions over many recent years, owing to their desirable adsorption–desorption performance and exceptional thermo-oxidative stability compared to virtually any other capture materials typically the wide array of amine-based sorbent materials. However, due to the nature of physical adsorption, virtually none of the carbon materials reported so far can be practically used for PCC applications without deep flue gas cooling to ambient or even lower temperatures in order to achieve appreciable levels of CO2 uptake capacities at low CO2 partial pressures. Here, we present a category of 3D hierarchical molecular sieving carbon architectures that are able to operate at realistic flue gas temperatures with exceedingly high reversible CO2 capacities. The breakthrough CO2-sieving carbon materials are prepared from using a cost-effective and commercially widely available precursor of polymeric polyisocyanurates with a facile one-step compaction–activation methodology. Tested at sensible flue gas temperatures of 40–70 °C and a low CO2 partial pressure of 0.15 bar, the best performing materials are found to have exceedingly high reversible CO2 capacities of up to 2.30 mmol g−1 at 40 °C and 1.90 mmol g−1 at 70 °C. Advanced characterisations suggest that the unique geometry and chemistry of the easily available precursor material coupled with the characteristics of the compaction–activation protocol used are responsible for the CO2-sieving structures and capacities of the 3D carbon architectures. The findings essentially change the general perception that carbon-based materials can hardly find applications in post-combustion capture due to their low CO2 uptake capacity at low CO2 partial pressures and realistic flue gas temperatures.

The effective outlier detection method is an important technique in the process of product quality monitoring. In this work, a novel Kohonen one-class model coupled with artificial lipid membrane taste sensors was proposed for tea quality control. Firstly, the taste information of five different grades of Tieguanyin tea was obtained based on the artificial lipid membrane sensors. Secondly, an improved Kohonen model based on the average Hausdorff distance was proposed to enhance the matching degree and transform the multi-class model into a one-class model. Thirdly, a rejection rate was proposed to optimize the domain boundary, which affected the classification performance. Finally, the F1-score was introduced to evaluate the classification performance of the one-class model. The results indicated that the F1-scores for five different grades of Tieguanyin tea were 0.952, 0.947, 0.952, 1 and 0.947, respectively, and an average F1-score of 0.9596 was obtained. This study shows that the novel Kohonen one-class model coupled with the artificial lipid membrane taste sensors can be used as an effective outlier detection method for quality control of tea.

Amyloid fibrils, implicated in health and diseases, commonly exhibit a periodic twist trait relevant to the structures and dynamics of the fibrils. However, the origins and modulations of fibril twist in complex in vivo environments are not yet fully understood. Here we highlight an important factor that causes twist variations in amyloid fibril structures-the presence of surrounding surfaces. Using cholesterol-containing lipid bilayers with varying cholesterol contents, we have demonstrated via atomic force microscopy that amyloid-β peptide fibrils initiated on membranes increase their average pitch size of twisting periodicity as the cholesterol content increases. These surface-induced twist variations arise from the enhanced hydrophobic interactions between the fibril and the surface distorting the torsional elastic energy of the fibril twisting as supported by a theory of an elastic model. These findings not only provide an important insight into fibril polymorphism phenomena resulting from the surface effects but also suggest a novel solution to modulate filament twisting on the nanoscale for biomaterials applications involving nanoscale features.

A series of cerium-doped iron–titanium composite oxide catalysts (FeCeaTi, a = 0.1–1.0) prepared by a urea homogeneous precipitation method were investigated for selective catalytic reduction of NOx with NH3 (NH3-SCR). Over all the FeCeaTi samples, a promotion effect for NOx reduction was induced by the introduction of cerium, with the FeCe0.3Ti catalyst exhibiting the best catalytic performance, even at a high GHSV of 250 000 h−1. As indicated by kinetic studies, interestingly, the FeCe0.3Ti catalyst exhibited a higher activation energy for the NH3-SCR process while possessing a pre-exponential factor three orders of magnitude higher than that of FeTi. Going deeper, extensive characterization including N2-physisorption, XRD, Raman, NH3/NOx-TPD, XPS, EPR, and H2-TPR was carried out. XRD and Raman results showed that the introduction of suitable amounts of Ce into the FeTi samples promoted the dispersion of Fe and Ti. Such higher dispersion of these two components increased the capacities for NOx adsorption and activation and weakly bonded ammonia over FeCe0.3Ti, thus promoting the occurrence of the L–H pathway of NH3-SCR at low temperatures. H2-TPR results indicated that the reduction of FeCe0.3Ti occurred at a higher temperature than that of FeTi, which may be a reason for its higher activation energy for NH3-SCR.

Polymer dielectrics with high energy density can be realized in high-k polymers, but undesirable energy loss always occurs, especially at high electric field and elevated temperature application. By systematically comparing the dielectric and energy storage properties of poly(styrene-methyl methacrylate)s (P(St-MMA)s) with PSt and PMMA homopolymers, the positive roles of the MMA units in the improvement of their dielectric and energy storage properties are well addressed. The best electric performance, including the largest Ue of 12.2 J cm-3, η of 92%, and Eb of 530 MV m-1 at ambient temperature, was obtained in the copolymer bearing 45 mol% MMA. Considering the different types of dipoles and the generated intermolecular forces, the influence of MMA on the dielectric performances of the copolymers is well illustrated. Instead of permanent dipoles alone, the combination of isolated permanent dipoles together with induced dipoles may be promising for realizing high-k, high energy density and low loss. This conclusion helps to understand the dielectric performances of polymer dielectrics from an intermolecular force point of view and proposes a strategy for realizing high energy density but low loss under a high electric field in polymer dielectrics.

This paper demonstrates a rational protocol for the synthesis of ultrasmall bimetallic alloy nanoparticles (FeCo, FeNi, and NiCo

Polymer dielectrics with high energy density (Ue) and low energy loss (Ul) under elevated electric fields and temperatures are in urgent demand for next-generation energy storage devices, e.g., high-pulse film capacitors. To overcome their long-standing tradeoff between high Ue and low Ul, a series of flexible glassy poly(styrene-methyl methacrylate-methallyl alcohol) (P(St-MMA-MAA)) terpolymers with promising dielectric and physical properties, including improved tunable permittivity (3–6 range), thermal stability, and processability, are investigated and compared to the commercially available state-of-the-art polymer dielectric, i.e., biaxially oriented polypropylene. The benzyl groups of the low-polarity polystyrene matrix suppressed the aggregation of polar units under high energy fields, i.e., diminishing the aggregation caused energy loss in the capacitive terpolymers. The hydroxyl groups on MAA units are designed to establish H-bonds between hydroxyl and ester groups, which favor the enhancement of glass transition temperature, dielectric constant, Young's modulus, and breakdown strength of polymers. As a result, a discharge energy density of 14.5 J cm−3 with a high efficiency of 93% at 700 MV m−1 is achieved. This work demonstrates that dispersing isolated dipoles into a low-polarity polymer matrix with high glass transition temperature is an effective strategy for suppressing the energy loss induced by the orientation of aggregated dipoles and creates a new avenue for high-energy and low-loss flexible capacitors.

Dielectric polymer film capacitors with high energy density and low energy loss are highly desirable in compact electronic devices and high power density electric systems. To overcome the high dielectric loss of poly(vinylidene fluoride) based ferroelectric polymers, in this work, a series of antiferroelectric-like poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene)-graft-poly(styrene-methyl methacrylate) (PVDF-MS) copolymers were successfully synthesized using an atom transfer radical polymerization procedure. The merits including the excellent miscibility of PMMA with both PSt and PVDF, and the promising insulating performance of PSt segments are combined in the resultant copolymers. The introduction of increased P(St-MMA) (MS) side chains leads to significantly enhanced energy density, low conduction loss and energy loss compared with the pristine P(VDF-TrFE-CTFE). The highest energy density of 17 J cm−3 and the discharge efficiency of 87% at 600 MV m−1 are achieved by the sample containing 28 wt% MS. The excellent dielectric and capacitive properties of the grafted copolymers offer a strategy for the synthesis of high dielectric polymer dielectrics with promising energy storage properties.

Self-assembly of non-spherical building blocks offers a potential route to photonic crystal supraparticles (PCSs) with novel structures and optical properties. However, experimental fabrications of anisotropic-particle-based PCSs have rarely been demonstrated owing to the requirement of additional control over the particle orientation during the assembly process. Here, we develop a spatially confined magnetic assembly strategy for the tailored assembly of ellipsoidal particles into PCSs with unusual non-close-packed structures. Detailed studies reveal that the transition of these metastable structures into close-packed structures is kinetically inhibited during the drying process owing to the synergy of spatial confinement and magnetic alignment. Unlike conventional PCSs, the nanoellipsoid-based PCSs exhibit anisotropic optical properties and multiple magneto-optical responses. The present work not only provides a model system for studying colloidal assembly under spatially confined conditions but also greatly extends the family of PCSs with interesting structures and properties, bringing new opportunities for applications in various areas.

Solar vapor generation is an efficient way to use solar energy for seawater desalination and sewage purification. The efficient utilization of solar-generated heat is a critical and hot topic for developing one-sun driven highly efficient solar vapor generation devices. Here, we reported a three-dimensional graphene-based hive (GBH) solar evaporator that can ensure efficient heat utilization by hierarchical heat trapping and efficient heat localization and reflux as well as long-term heat storage. As a result, a significant efficiency improvement (∼9%) was demonstrated in the 3D GBH evaporator from the initial 1.95 kg m−2 h−1 (corresponding to an energy efficiency of ∼85%) to the subsequent 2.13 kg m−2 h−1. In addition, the GBH evaporator exhibited an excellent water evaporation performance under discontinuous irradiation that is 81% of that achieved by continuous solar irradiation for one hour at 1 kW m−2. The promising 3D hierarchical design offers efficient heat trapping, localization, and reflux as well as long-term heat storage which make it easy to develop highly efficient solar vapor generation devices for sunny and cloudy days.

Energy collection and molecular separation are two emerging applications based on membrane technologies. It remains a challenge to improve the separation performance of molecular channels. Meanwhile, the application of membranes is typically impeded by their poor stability under practical hydrous conditions. Herein, we present the fabrication of a uniformly lamellar membrane using montmorillonite nanosheets as building blocks. We managed to achieve nanofluidic ion transport and molecular separation simultaneously. The membrane nanochannels possess nanofluidic ion transport properties with an output power density of up to 0.18 W m−1 at a membrane thickness of 11.2 μm under a 1000-fold transmembrane concentration difference. The membrane also shows a water permeance of 429 L m−2 h−1 atm−1 at a thickness of 2.5 μm and high separation efficiency for both cationic and anionic dyes. Moreover, the montmorillonite-based membranes can maintain high stability under aqueous conditions with soaking, shaking, and even ultrasonication.

Cations and anions attract each other by electrostatic force to form an ion pair. However, repulsion between cations and anions does exist. There are few examples of repulsive “ion pair strain” where catalysis by a strained ion pair is absent. Here, we describe substituted cyclopropenium, the minimal Huckel aromatic ring, which when mounted with PhNH groups on the positive cyclopropenium core C3, behaves as an electron-rich cation to repel its counter negative anion. The formal positive charge on C3 turns the NH moiety into a strong H-bond donor (HBD) and the weakly coordinating chloride exhibits strong H-bond acceptor (HBA) character. The strained ion pair composed of a HBD and a HBA displays cooperative organocatalysis in ring-opening polymerizations of δ-valerolactone initiated with benzyl alcohol. A cooperative catalysis mechanism of tris(phenylamino)cyclopropenium as a HBD and chloride as a HBA was elucidated.

A naphthalimide-derived fluorescent sensor termed L2 was designed and synthesized. This sensor showed a highly selective, sensitive, and reversible turn-on response to Cd2+ over other metal ions in a wide pH range with a detection limit of 2.35 × 10−10 M. The amide/di-2-picolylamine receptor binds Cd2+ in the imidic acid tautomeric form but other metal ions in the amide tautomeric form. Moreover, the sensor can be used to distinguish Cd2+ and Zn2+ with the naked eye. The Cd2+-binding mode and the recognition mechanism of the sensor were investigated using Job's plot, 1H NMR, HRMS, IR and DFT calculations. Furthermore, the sensor was successfully applied as the active component of indicator papers for on-site detection of Cd2+ in pure water and in fluorescence imaging of Cd2+ in HeLa cells.

To minimize the voltage loss of non-fullerene organic solar cells (OSCs), it is important to modulate the energy levels of active materials and thus the photovoltage of the device. In this paper, we report a simple and effective approach to tune the energy levels of a state-of-the-art polymer P3TEA by switching the position of alkyl side chains and carboxylate substituents on the polymer backbone. The resulting polymer P3TAE exhibits a deep highest occupied molecular orbital (HOMO) level, contributing to a high open circuit voltage (VOC) of 1.20 V and a small voltage loss of 0.54 V when it is blended with a small molecule acceptor (SMA) FTTB-PDI4. Despite a small charge separation driving force, the P3TAE:FTTB-PDI4 blend exhibits efficient charge extraction, supported by relatively high external quantum efficiency (EQE) (∼60%) in the corresponding device. In addition, the P3TAE:FTTB-PDI4 blend shows relatively high electron mobility and domain purity, leading to a high fill factor (FF) in the device. As a result, the P3TAE:FTTB-PDI4-based solar cell exhibits a power conversion efficiency (PCE) of 8.10%, which is one of the highest achieved performances for single-junction OSCs with VOC higher than 1.20 V.

The effective feature mining method is one of the key problems in the field of pattern recognition. Moreover, the lack of efficient feature extraction and selection methods has limited the application and development of electronic nose (e-nose) technology. In this study, a synergetic strategy for e-nose sensors data feature mining was proposed in combination with Support Vector Machine (SVM) to determine the beer olfactory information. First, twenty time-domain features and twenty frequency-domain features of e-nose sensors data were extracted to represent the olfactory characteristics of beer. Second, forty features were sorted with variable importance in projection (VIP) scores and forty subsets of multi-features with the best VIP score were generated. Finally, the classification models were established based on SVM, and the best parameter c and g of SVM models was calculated by Genetic Algorithm (GA). Furthermore, the classification performance of each class was evaluated by efficiency value (EFF) in different feature sets. The result indicates that GA-SVM model achieves good classification performance based on the #27 feature set with 81.67% and 96.67% in calibration set and testing set, respectively, and the EFF value is also the highest compared with other feature sets. In conclusion, it indicated that the analytical method can be used as a reliable tool for accurate identification of beer olfactory information.

The grafting of poly(methacrylate ester) or polystyrene onto the side chain of poly(vinylidene fluoride) (PVDF)-based fluoropolymers maintains their high energy density and remarkably reduces the energy loss due to the confinement (or insulation) effect, which has potential application in high-pulse capacitors. The graft copolymers were previously synthesized from C–Cl bonds via the transition metal-catalyzed atom transfer radical polymerization (ATRP) process. To overcome the negative influence of the residual metal ions from the catalyst on the dielectric properties of the resultant copolymers, in the present contribution, a facile strategy is reported for photo-mediated ATRP using organic-based photoredox catalysts to directly synthesize a poly(methyl methacrylate) (PMMA)-grafted copolymer from the commercial poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF–CTFE)). The graft copolymerization is efficiently activated and deactivated with light and exhibits first-order kinetics. The detailed structural information of the graft copolymer, including average grafting density and side chain length, are also determined by converting the uninitiated Cl atoms into H atoms. When compared with the traditional Cu-catalyzed ATRP process, the current photo-induced ATRP method used for preparing the graft copolymer results in improved dielectric performances such as reduced dielectric loss at low frequency and high temperature, decreased conduction loss, and enhanced breakdown strength.

Aliphatic polyesters are broadly used in biomedical materials, food packaging and drug delivery. The use of catalytic ring-opening polymerization (ROP) by dual catalysis, combining organocatalysis and metal complex catalysis, is a powerful strategy toward these valuable polyesters. In an endeavor to combine metal catalysis and organocatalysis in polymerization, we suggested the use of metal salts of an organophosphoric acid as bifunctional catalysts in the ROP of cyclic esters and of cyclic carbonates. Four metal organophosphates, viz. lithium, sodium, magnesium, and calcium diphenyl phosphates, were evaluated as catalysts for the ROPs of trimethylene carbonate (TMC), δ-valerolactone and lactide with 3-phenyl-1-propanol (PPA) as an initiator for obtaining aliphatic polyesters. Magnesium diphenyl phosphate (MgDP) showed relatively high catalytic activity and ideal control. The molecular weights of the PTMCs measured using 1H NMR matched well with the theoretical ones. 1H NMR, 13C NMR, and MALDI-ToF MS measurements demonstrated that the initiator and monomer polymerized quantitatively. Bulk polymerization with various [TMC]0/[PPA]0/[MgDP]0 ratios afforded PTMCs with expected molecular weights (Mn, NMR = 3.21–11.7 kg mol−1) and relatively narrow dispersities (Mw/Mn = 1.16–1.19). Kinetic studies, chain extension experiments and diblock copolymer synthesis were carried out to identify that the MgDP-catalyzed ROP proceeded in a controlled/living manner. A bifunctional catalytic mechanism for the MgDP catalyzed ROP was suggested from 1H NMR, 13C NMR and 31P NMR titration experiments. For evaluating the biosafety of the PTMC produced in the bulk ROP under MgDP catalysis, untreated PTMC samples were tested by an MTT assay using the L929 cell line. A result of more than 90% relative cell viabilities demonstrates the excellent cell compatibility of the PTMCs for potential biomedical applications.

Hydrogen sulfide (H2S) is a signaling gasotransmitter that plays important roles in modulating the functions of different systems. We have designed and synthesized a 3-hydroxychromone-based fluorescent probe A for H2S detection. Probe A is based on a H2S-induced thiolysis reaction and an excited-state intramolecular proton transfer (ESIPT) process. The probe shows high selectivity and sensitivity for the detection of H2S over glutathione, cysteine and homocysteine. Moreover, this probe was successfully applied for imaging exogenous and endogenous H2S in living cells.

The construction of flexible and stretchable supercapacitors with high energy density and superior stability is critical for modern wearable electronics but still remains considerably challenging. Herein we develop an ultrahigh-performance stretchable asymmetric supercapacitor (SASC) by using electrically and mechanically robust three-dimensional graphene frameworks as electrodes for the first time, in which three-dimensional graphene and a deliberately designed three-dimensional graphene/polyaniline composite are employed as the anode and cathode, respectively. The newly developed SASCs show the highest energy density of 77.8 W h kg−1 among all reported stretchable supercapacitors, and also deliver exceptional cycling stability with 95.6% capacitance retention after 10 000 charge–discharge cycles and excellent electrochemical durability with 91.2% capacitance retention after 100 stretching cycles at a large strain of 100%. The practicability of our SASC has been further demonstrated by efficiently powering a light-emitting diode indicator (1.8 V, 10 mA) under repeated stretching of a SASC mounted on a finger. Moreover, by connecting three SASCs in series, the tandem device can even drive an STC89C51RC microcontroller-based complex circuit (5.0 V) to light a liquid crystal display.

Solid-state electrolytes (SSEs) are potential candidates for developing high-energy-density and safe all-solid-state lithium (Li)-metal batteries due to the elimination of most of the safety issues encountered with liquid electrolytes. However, unfortunately, dangerous Li dendrites still form in SSEs. Herein, we report a simple nano-polishing method to prepare a high-performance all-solid-sate Li–air battery that consists of an air cathode, Li metal anode and ultra-fine surface Li1.5Al0.5Ge1.5P3O12 (LAGP) electrolyte. Such a design effectively reduces the interface impedance of the battery and meanwhile creates an ultra-smooth/flat interface between the Li metal and LAGP electrolyte that can produce a uniform electric field across the interface, thus enabling a homogeneous metal Li-forming/deforming environment during discharge/charge processes. As a result, a long cycle life all-solid-state Li–air battery has been obtained at room temperature at 400 mA g−1 with a capacity limitation of 1000 mA h g−1. The experimental results reveal that Li dendrites are suppressed through eliminating protrusion-induced locally concentrated free electron density on the surface of Li metal. The present ultra-fine interface engineering may be robust enough to suppress Li-dendrites, providing new insights into the interface between the Li-metal and SSE to develop future all solid-state Li-metal batteries.

Carrageenan fiber (CAF) was prepared by a wet spinning method to develop an excellent flame-retardant material. In order to investigate the flame-retardant mechanism of CAF, a series of tests were carried out. The values of limiting oxygen index (LOI), total heat release (THR), and total smoke release (TSR) of CAF reached up to 52, 2.9 MJ m−2, and 2.5 m2 m−2, respectively, while there was no Time To Ignition (TTI) in cone calorimeter (CONE). These results indicate that CAF exhibits superior flame-retardant performance than other alginate fibers. Thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy (TG-DSC-FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) tests were performed in order to explore the pyrolysis mechanism. The results show that CAF absorbed more heat and produced more carbon residue than calcium alginate fiber (ALF) and agar fiber (AGF) in the process of thermal degradation. In addition, in the current work, we have explored the possible flame-retardant mechanisms which can be attributed to sulfonyl free radical (SFR), carbon residue, barium sulfate, water vapor, and carbon dioxide.

We have fabricated two types of plasmonic nanotextured devices (PNDs) using natural lithography technology, which have been applied experimentally in sensing volatile organic solutions (VOS). The PNDs were composed of the hybrid of metal/dielectric structures (PND-1) and metal/dielectric/semiconductor structures (PND-2). They were integrated with microfluidic chips and compared with and without injecting various types of solutions, i.e. DI water, ethanol (C2H5OH), isopropanol (C3H7OH), and ethanediol (C2H4(OH)2). Plasmonic coupling and energy confinement in the PNDs induced a noticeably resonance narrowing of the spectral reflection in the ultra-violet (UV) light region, in which the FWHM (Full-Width at Half-Maximum) was around 20 nm. The experimental results indicate that the sensitivities of the devices are 38.6 nm RIU−1 and 70.8 nm RIU−1 for PND-1 and PND-2, respectively, of which PND-2 is enhanced 1.8-fold compared to PND-1. This sensing approach with high portability, applicability, and cost-effectiveness using plasmonic nanotextured surface based devices may minimize the limitations of time and space in environmental monitoring, food safety and other fields.

Ring-opening polymerization (ROP) of lactones catalyzed by a (super)strong Bronsted acid offers a valuable approach to important biodegradable aliphatic polyesters. However, the need for a mild acidic catalyst in ROP has been long sought after but unmet. Here, we describe a truly weak Bronsted acid, benzoic acid, in combination with a dual H-bond donor (dHBD), which catalyzes the ROP of δ-valerolactone (VL) in solution at room temperature. A unique preorganized sulfonyl guanidine type of dHBD, 3-amino-1,2,4-benzothiadiazine-1,1-dioxide (ABTD), proves optimal to work with benzoic acid as a cocatalyst, promoting benzoic acid activity in the ROP of VL. Poly-δ-valerolactones of predictable molecular weights (from 2.13 to 9.33 kg mol−1) and narrow dispersities (Đ ≤ 1.16) are synthesized. The controlled character of the ROP is verified by NMR, SEC, and MALDI-ToF MS measurements. NMR titration experiments imply that ABTD preferentially binds with benzoic acid, and the benzoic acid/ABTD pair protonates the VL monomer. Weak benzoic acid is not weak for the first time in the efficient cationic ROP of VL by the protonation mechanism.

The reaction mechanism of Ni(COD)2 catalyzed hydrodesulfurization of aryl sulfide PhSMe with HSiMe3 as the reducing agent has been studied by using density functional theory methods. Both PhSMe-coordinated pathway and “ligandless” pathway have been identified and compared. It is found that these two reaction pathways are kinetically competitive and the σ-complex assisted metathesis (σ-CAM) transition state is the highest point on each energy profile for both pathways. Moreover, both the singlet and triplet reaction pathways of ligand substitutions have been compared and found that both singlet and triplet reaction mechanisms are competitive for the ligand substitution of COD with PhSMe on PhSMe-coordinated pathway while the triplet mechanism holds a distinct advantage over singlet one for that of COD with HSiMe3 on “ligandless” pathway.

Ring-opening polymerization (ROP) of lactones and cyclic carbonates catalyzed by (super)strong Bronsted acids offers a valuable approach to generate biodegradable aliphatic polyesters. However, these strong acids usually lead to backbiting and decarboxylation; thus a mild and effective acidic catalysis for these ROPs becomes necessary. Inspired by weak Bronsted acidic catalysis in squalene–hopene cyclases, we propose that ortho-amido group(s) on benzoic acids would increase the acidity of the carboxylic moiety by intramolecular H-bonding, and make carboxylic acid active in promoting the ROPs. A series of o-amido- and o,o′-bis(amido)-benzoic acids are evaluated as typical intramolecular H-bonding enhanced Bronsted acidic catalysts in the ROPs. Both o-amido- and o,o′-bis(amido)-benzoic acids exhibited good to excellent performances in the rate and control of ROPs of δ-valerolactone (VL), e-caprolactone (CL), and trimethylene carbonate (TMC) at room temperature in solutions. An exceptional carboxylic acid, o,o′-bis(pivalamido)benzoic acid, showed efficient activation in solution and precise control with high conversions (91–96%), predicted molecular weights from 3.09 to 10.31 kg mol−1, and narrow dispersities (Đ 1.03–1.12) in ROPs of CL and TMC. Well-defined diblock copolymers consisting of PTMC, PVL and PCL segments were synthesized. The controlled/living characteristics of the ROPs were verified by chain extension experiments. 1H NMR, SEC, and MALDI-TOF MS analyses strongly indicated that the obtained polymers were exactly the designated ones. A cationic monomer activation mechanism was proposed and was supported by NMR titrations. The experimental results indicated that mild and tunable ortho-amido benzoic acid with intramolecular H-bonding is a competent organocatalyst in living polymerization.

A robust embedded three-electrode microfluidic chip (TEMC) was designed for the in situ electrochemical synthesis of polyaniline (PANI) nanostructures. PANI doped with poly-vinylsulphonic acid (PVS) was electrochemically produced at a channel coated with a thin gold layer as the working electrode material. The resultant material formed a conductive monolithic PANI/PVS film with cotton-like nanostructures. The thickness and porosity of the polymeric material can be controlled by the polymerization conditions, i.e., the number of potential cycles. Horseradish peroxidase (HRP) was subsequently electrostatically immobilized on the monolithic PANI/PVS film. This modified PANI/PVS/HRP material, obtained using a TEMC, showed a good linear response over a range of 0.01–0.6 mM and 1–60 mM for hydrogen peroxide detection and exhibited good reproducibility. This TEMC design could provide a simple and reliable approach for enzyme-based biosensor fabrication.

Carbon monoxide (CO) is known for its multifaceted role in human physiology, and molecules that release CO in a controlled way have been proposed as therapeutic drugs. In this work, a light-responsive CO-releasing molecule (CORM-Dabsyl) showed a strong colourimetric response upon photochemical CO-release, owing to the tight conjugation of a Mn(i) tricarbonyl centre to a dabsyl chromophoric ligand (L). Whereas the complex was very stable in the dark in nitrogen-purged aqueous media, CO-release was effectively triggered using 405 nm irradiation. CORM-Dabsyl, L and the inactive product iCORM-Dabsyl have been investigated by DFT and TD-DFT calculations. Only mild toxicity of CORM-Dabsyl was observed against LX-2 and HepaRG® human cell lines (IC50 ∼ 30 μM). Finally, to develop a CO storage and release material that is readily applicable to therapeutic situations, CORM-Dabsyl was loaded on low-cost and easily disposable paper strips, from which the light triggered CO-release was conveniently visible with the naked eye.

Here we report a unique hierarchical free-standing graphene/polyaniline (G/PANI) composite electrode with ultrathin G/PANI composite nanosheets embedded in the skeleton of a three-dimensional (3D) graphene framework. Due to the intrinsic structural advantage of ultrathin G/PANI composite nanosheets and their synergetic interaction with the 3D graphene network, the 3D-G/PANI composite electrode can deliver a high specific capacitance of 777 F g−1 and 990 F cm−3 at 1 A g−1 and an exceptional cycling stability with 85% capacitance retention after 60 000 deep cycles in a three-electrode cell configuration. The further assembled all-solid-state supercapacitor based on the 3D-G/PANI composite electrode can not only show extraordinary mechanical flexibility allowing bending, twisting and folding, but also demonstrate remarkable electrochemical performance under its folded state, including an ultrahigh specific capacitance of 665 F g−1 and 847 F cm−3 for the 3D-G/PANI composite electrode, excellent rate capability with a capacitance retention of 86% at 20 A g−1 and superior cycling stability with no capacitance decay after 10 000 cycles, as well as ultralow self-discharge characteristics. Furthermore, the entire ultrathin device (∼45 μm, much thinner than a commercial standard A4 paper) can deliver volumetric, gravimetric and areal energy densities up to 14.2 mW h cm−3, 10.9 W h kg−1 and 64 μW h cm−2, respectively, which are much higher than those of current high-level commercial supercapacitors (∼5 W h kg−1) and even lithium thin-film batteries (∼8 mW h cm−3, 4 V/500 μA h).

Herein we report a facile mechanochemical synthesis of 2D aromatic polyamides (2DAPAs) under solvent-free and room temperature conditions for the first time. The solvent-free conditions are found to be key to the successful synthesis of 2DAPAs. These micrometer-size 2DAPAs have ultrathin graphene-like structures and are highly crystalline, solvent dispersible and thermally stable up to 400 °C.

Multiple combinations of six squaramides (Sq) and eight amines as the co-catalysts were tried in ring-opening polymerizations (ROPs) of cyclic carbonates, lactones, and lactides. Sq and sparteine co-catalysts enabled ROPs of trimethylene carbonate (TMC) to poly(trimethylene carbonates) (PTMCs) with benzyl alcohol (BnOH) as the initiator. The polymerization proceeded in 3 to 16 h without decarboxylation to afford polycarbonates with precise molecular weights (Mn,NMR = 1.95 to 10.1 kg mol−1) and narrow polydispersity indices (Đ = 1.12–1.17). 1H NMR, SEC and MALDI-ToF MS measurements of the obtained PTMCs clearly indicated the quantitative incorporation of the initiator at the chain end. Kinetics and chain extension experiments demonstrated the controlled/living nature for the ROP of TMC using Sq and sparteine. NMR titration experiments confirmed that the polymerization proceeded in a H-bonding dual activation mechanism. In addition, 1,3-propanediol, pentaerythritol, propargyl alcohol, furfuryl alcohol and N-(2-hydroxyethyl)maleimide were used as functional initiators leading to production of α,ω-dihydroxy telechelic, star-shaped, and clickable end-functionalized polycarbonates. Homopolymers of valerolactone (VL), caprolactone (CL), and lactide (LA) and diblock copolymers PVL-b-PTMC and PCL-b-PTMC were successfully synthesized by using Sq and 1,8-diazabicyclo[5.4.0]undec-7-ene binary co-catalysts with BnOH as the initiator in dichloromethane at room temperature. Block copolymers PTMC-b-PVL, PTMC-b-PCL, and PTMC-b-PLA were successfully obtained by using the binary catalysts. Squaramides combined with amine co-catalysts are a generally applicable polymerization tool.

One-dimensional (1D) small-molecule semiconducting nanostructures (NSs) have attracted more and more attention due to their unique structures and photoelectric properties. However, the preparation of real ultrafine 1D organic nanocrystals (ONCs), in which the intermolecular charge transfer (CT) is confined to a 1D direction, is still a huge challenge. Here, we report a facile way to controllably synthesize uniform 1D ONCs of μ-oxo dimeric iron(III) porphyrin [(FeTPP)2O] in a cetyltrimethyl ammonium bromide (CTAB)-assisted wet chemical reaction (WCR). In this work, the shape evolution of the (FeTPP)2O NSs was shown by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Interestingly, the regularity and aspect ratio of the (FeTPP)2O 1D NCs increased with time, while their diameters decreased. Further experiments proved that this was closely associated to the reconstruction of the CTAB micelles. After optimizing the experimental conditions, we not only synthesized uniform 1D ONCs with a width of ∼28 nm and/or an aspect ratio of ∼37, but also obtained 2D ONCs with a thickness of about 10 nm. Here, the finest 1D ONCs that we have seen to date have been prepared. The corresponding UV-vis absorption and photoluminescence (PL) spectra are enhanced with a decrease in the diameter and an increase in the aspect ratio of (FeTPP)2O 1D ONCs with high crystallinity, which clearly shows the first report of the confinement effect of the intermolecular CT state in 1D ONCs. This work paves a new route to prepare 1D ONCs and provides us with a chance to further understand and apply the intermolecular CT in 1D organic photoelectrical devices.

Given the complexity of tumors, several nanomaterial-based treatment modalities like chemotherapy (CT), photodynamic therapy (PDT) and photothermal therapy (PTT) have been developed for combating cancers. However, it is still unclear which strategy is better or how to select optimal approaches for combination treatment since each strategy has been investigated under different conditions. Inspired by its good payload capacity and unique near-infrared absorption, reduced graphene oxide (rGO) was selected in this study as the carrier for loading of doxorubicin (DOX), a chemotherapy drug, and chlorin e6 (Ce6), a photosensitizer. The therapeutic efficacies of PTT, CT and PDT were systematically investigated in vitro using 2D culture and multicellular tumor spheroid (3D) models. Interestingly, while all three types of therapies delivered by rGO appeared to be effective in the conventional 2D cell culture model, only PTT but not CT and PDT showed great treatment efficacy in the 3D tumor spheroid model at the tested concentrations. Such a difference is due to the fact that heat diffusion is much more efficient than the diffusion of therapeutic molecules inside the tumor. Furthermore, in vivo evidence also confirmed the unique advantage of PTT compared to the other two treatment modalities using the TdT-mediated dUTP nick end labeling (TUNEL) staining assay. This study highlights the unique advantages of nanomedicine-based photothermal therapy among these three modalities in cancer treatment in terms of killing tumor cells located far from tumor blood vessels.