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Off-label drug use embodies a thorough clinical diagnosis and evaluation of treatment needs and should not be confused with unreasonable drug use, but it also faces potential risks with drug safety and legal issues.We first established a guideline working group. Following the guideline development process recommended by the World Health Organization Handbook and the Chinese Medical Association, the key questions were determined through literature searches of PubMed, CNKI (Chinese National Knowledge Infrastructure) and other databases. Both the evidence and the clinicians' diagnosis and treatment workload were considered to formulate the initial recommendations. Finally, two rounds of Delphi surveys and one expert seminar were organized to determine the final recommendations of this guideline. Meanwhile, we graded the recommendations based on the body of evidence.We determined nine questions and proposed a total of 23 recommendations regarding the definition of off-label use of drugs, applicable circumstances, classification of evidence, informed consent, legal basis, adverse drug reaction monitoring and evaluation, management procedure, responsibilities and obligations of different stakeholders, medical insurance reimbursement, and the national approval system.This guideline standardized clinical off-label drug use and provided suggestions and references for the management of off-label drug use.

A precisely fabricated conductive MOF incorporating unique host–guest interactions can be used to achieve active-site integration and effective electrocatalytic C–N bond coupling for the synthesis of urea.

The design of efficient and stable oxygen evolution reaction (OER) catalysts based on noble-metal-free materials is crucial for energy conversion and storage. In this work, it was demonstrated how polyoxometalate (POM)-doped ZIF-67 can be converted into a stable oxygen evolution electrocatalyst by chemical etching, cation exchange, and thermal annealing steps. Characterization by X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and Raman spectroscopy indicate that POM-doped ZIF-67 derived carbon-supported metal oxides were synthesized. The resulting composite shows structural and compositional advantages which lead to low overpotential (306 mV at j=10 mA ⋅ cm−2) and long-term stability under harsh OER conditions (1.0 M aqueous KOH).

The simultaneous electrocatalytic conversion of N2 and CO2 into value-added urea is highly anticipated but suffers from the predicament of the poor chemisorption, activation, and coupling activity of reactant molecules. Herein, unique frustrated Lewis pairs (FLPs) were precisely designed in flower-like nickel borate [Ni3(BO3)2], where the surface hydroxyl and neighboring Ni site serve as a Lewis base and acid, respectively. Comprehensive investigations endorsed that the Lewis basic and acidic sites in FLPs acted synergistically in the targeted capture of inert CO2 and N2 by orbital interaction. Subsequently, the bonding and antibonding orbitals of the inert gas interacted with the empty orbitals of the Lewis acid and nonbonding orbitals of the Lewis base, respectively, achieving molecule activation by FLPs. Afterward, the *NN* and CO intermediates underwent electrocatalytic C–N coupling by the σ orbital carbonylation strategy to produce *NCON* precursors. Thus, the prepared Ni3(BO3)2-150 nanocrystal delivered the record-highest urea yield rate of 9.70 mmol h−1 gcat−1 and a Faradaic efficiency of 20.36% at −0.5 V vs. RHE.

Face-dependent bulk nanostructuring of Cu metal electrodes is reported, leading to Janus-type electrodes where one face features Cu(OH)2 nanowires while the other face is decorated with CuO nanoflowers. Thermal conversion into CuxO nanowires/nanoflowers as well as chemical reduction to elemental Cu nanowires/nanoflowers demonstrate the versatility of the approach. Initial electrocatalytic studies show the electrochemical reactivity of the composite electrodes.The stable deposition of reactive nanostructures on metal electrodes is a key process for modern technologies including energy conversion/ storage, electrocatalysis or sensing. Here a facile, scalable route is reported, which allows the bulk nanostructuring of copper foam electrodes with metal, metal oxide or metal hydroxide nanostructures. A concentration-gradient driven synthetic approach enables the fabrication of Janus-type electrodes where one face features Cu(OH)2 nanowires, while the other face features CuO nanoflowers. Thermal or chemical conversion of the nanostructured surfaces into copper oxide or copper metal is possible whilst retaining the respective nanostructure morphologies. As proof of concept, the functionalized electrodes are promising in electrocatalytic water oxidation and water reduction reactions., publishedVersion

Energy crisis and global warming due to excessive CO2 emissions are the two major challenges of the world. Conversion of CO2 into useful fuels along with rechargeable metal air batteries and water ...

The top-down fabrication of catalytically active molecular metal oxide anions, or polyoxometalates, is virtually unexplored, although these materials offer unique possibilities, for catalysis, energy conversion and storage. Here, we report a novel top-down route, which enables the scalable synthesis and deposition of sub-nanometer molybdenum-oxo clusters on electrically conductive mesoporous carbon. The new approach uses a unique redox-cycling process to convert crystalline MoIVO2 particles into sub-nanometer molecular molybdenum-oxo clusters with a nuclearity of ∼1–20. The resulting molybdenum-oxo cluster/carbon composite shows outstanding, stable electrocatalytic performance for the oxygen reduction reaction with catalyst characteristics comparable to those of commercial Pt/C. This new material design could give access to a new class of highly reactive polyoxometalate-like metal oxo clusters as high-performance, earth abundant (electro-)catalysts., The top-down synthesis and deposition of polyoxometalate-like clusters on porous carbon is reported together with the high electrocatalytic oxygen reduction reactivity of the composite.

Defect engineering through heteroatom doping is one of the most important strategies towards the development of catalytic active materials for energy related applications. Herein, a novel trifunctional Br/Co/N Co-doped and defect-enriched porous carbon framework (BrHT@CoNC) is designed, which shows excellent electrocatalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as well as the hydrogen evolution reaction (HER). Introduction of extensive defects by heteroatom-doping is simply achieved by pyrolysis of the surfactant, dimethyldioctadecylammonium bromide (DODAB) modified ZIF-67. The BrHT@CoNC composite shows great potential as an economical catalyst/electrode for both rechargeable Zn–air batteries and overall water splitting devices. This work opens a new avenue toward the exploration of cost effective heteroatom doped catalysts for efficient integration of three or more functions into one freestanding electrode.

Polyoxometalate-like molybdenum(vi)-oxo clusters ([Mo-oxo]n, n = 1-20) deposited on high surface-area carbon are developed as a biosensor for non-enzymatic electrochemical H2O2 detection. The sensor exhibits excellent electrocatalytic performance with a low detection limit, wide linear range, excellent sensitivity and stability. The composite can be stably deposited on screen-printed electrodes which combine microlitre analyses, long shelf-life and re-usability.

Considering the very limited while varying information about the excretion of hydroxychloroquine (HCQ) into human milk, we sought to determine the breast milk concentrations of HCQ in Chinese lactating patients with connective tissue diseases to assess the safety of HCQ in infants of this population. Breastfeeding women who had been on HCQ for at least 1 year were recruited. Milk samples were collected at five time points over 12 h. Breast milk HCQ levels were measured by a validated high-performance liquid chromatography (HPLC) assay. According to the general daily milk consumption of 0.15 L/kg for an infant, the dose of HCQ received by the infants via breastfeeding was calculated. Thirty-three patients completed the study who received HCQ treatment with the following regimens: 0.1 g bid (n = 3), 0.2 g qd (n = 8), 0.2 g bid (n = 21), and 0.2 g qod (n = 1). The mean breast milk HCQ levels (μg/mL) over the 12-h sampling period for each dosage regimen group were 0.4, 0.7, 1.4, and 0.4, respectively. The dose of HCQ (mg) received by the infants via breastfeeding would be 0.4, 0.4, 0.9, and 0.2, which were 0.26%, 0.26%, 0.29%, and 0.26% of the daily maternal doses, respectively. The infant’s weight-adjusted relative dose (mg/kg) was 0.1, 0.1, 0.2, and 0.1, respectively, equivalent to 1.9%, 3.0%, 3.0%, and 3.2% of the maternal dose per kilogram body weight, respectively. Our study found that HCQ has very low concentrations in breast milk. It is probably safe for the patients to give breastfeeding during HCQ therapy period.

Polyoxometalate polymers with high proton conductivity are accessed for the first time by controlled covalent polymerization of Wells–Dawson-type niobotungstate and organoboronic acid monomers. The resulting polymer features a purely inorganic backbone, organic sidechains, and acts as a solid-state proton conductor. The controlled bottom‐up design of polymers with metal oxide backbones is a grand challenge in materials design, as it could give unique control over the resulting chemical properties. Herein, we report a 1D‐organo‐functionalized polyoxometalate polymer featuring a purely inorganic backbone. The polymer is self‐assembled from two types of monomers, inorganic Wells–Dawson‐type polyoxometalates, and aromatic organo‐boronates. Their covalent linkage results in 1D polymer strands, which combine an inorganic oxide backbone (based on B−O and Nb−O linkages) with functional organic side‐chains. The polymer shows high bulk proton conductivity of up to 1.59×10−1 S cm−1 at 90 °C and 98 % relative humidity. This synthetic approach could lead to a new class of organic–inorganic polymers where function can be designed by controlled tuning of the monomer units., publishedVersion

The development of scalable routes to highly active and efficient oxygen evolution reaction (OER) electrocatalysts based on earth-abundant materials is crucial for post-fossil fuel energy schemes. Here, we demonstrate how commercial copper foam electrodes can be functionalized for water oxidation using a facile electrodeposition process. The resulting composite electrode features hierarchically structured cobalt-iron-based catalyst particles, which offer channel-like structures for the transport of electrolyte and release of oxygen gas bubbles. We report high electrocatalytic OER performance as demonstrated by high current densities at low overpotentials (293 mV at j = 50 mA cm-2) and long-term stability under technologically relevant alkaline conditions (>24 h in 1.0 M aqueous KOH).

Polyoxometalate-like molybdenum(vi)-oxo clusters ([Mo-oxo]n, n = 1-20) deposited on high surface-area carbon are developed as a biosensor for non-enzymatic electrochemical H2O2 detection. The sensor exhibits excellent electrocatalytic performance with a low detection limit, wide linear range, excellent sensitivity and stability. The composite can be stably deposited on screen-printed electrodes which combine microlitre analyses, long shelf-life and re-usability.

Single-atom electrocatalysts have attracted board interest in the recent years as they combine the advantages of heterogeneous and homogeneous electrocatalysts. Nevertheless, single-atom electrocatalysts with single metal component cannot further satisfy the demand of catalytic properties. This work developed atomic Co/Ni dual sites in N-doped porous carbon Janus-like frameworks through epitaxial growth of cobalt based MOFs on nickel complexes. Structural characterization and atomic-scale transmission electron microscopy revealed the homogeneously dispersed active sites of Co-Ni alloy and single Co/Ni atoms. Electrochemical data strongly demonstrated the advantages of integrating Co-MOF and Ni complex with different topological structures to form a Janus-like structure. The resultant catalysts afforded onset potential of 0.93 V and half-wave potential of 0.84 V for oxygen reduction reaction in alkaline media, and 0.86 V and 0.73 V in acid media, which is better than single noble-metal-free catalysts, even close to commercial Pt/C. Besides, the catalysts also exhibited good oxygen evolution reaction performance (a current density of 10 mA cm−2 at a potential of 1.59 V) and overvoltage between ORR and OER is 0.78 V. Density functional theory calculations indicated the high electrocatalytic activities are originated from the synergetic effect of atomic Co/Ni-N-C bonds and microstructure of the prepared materials. This work paves a new avenue for the development of multiatomic electrocatalysts for energy conversion.

We report a convergent, modular materials design strategy, which gives access to multifunctional metal oxide/carbon composites for high-performance electrocatalysis and electrochemical energy storage. The materials design uses the thermal conversion of a metal organic framework (ZIF-67) functionalized with molecular vanadium oxide clusters ([V10O28]6−) to give a nanostructured composite where redox-active crystalline Co–V–oxide nanoparticles (∼5 nm) are firmly embedded in a high surface-area N-doped graphitic carbon matrix. The composite shows high activity, efficiency and stability for the electrocatalytic oxygen evolution reaction in alkaline conditions. In addition, proof of concept studies show fast and reversible Li storage behavior. Based on this new materials design principle, the divergent fields of electrocatalysis and battery materials design could be linked to enable a more efficient, converging materials design approach.

In this study, three different Ag micro/nano leaves were successfully synthesized through a galvanic displacement reaction by adjusting the concentration of Ag+. The catalytic activities of the prepared Ag micro/nano leaves toward ORR showed strong dependence on their morphology. An optimal concentration of Ag+ can result in a well-defined Ag micro/nano leaves with both crystallization and surface area, which showed the best activity towards ORR in alkaline media. In addition, the prepared Ag micro/nano leaves also showed high activity towards CO2 reduction, which required a potential of -0.8 V versus RHE to selectively convert CO2 to CO with the faradaic efficiency at about 20%. Compared with the Ag plate at the same overpotential, the FE has increased by 5-fold.

Novel Co atoms immobilized carbon nanotubes (CoSAs@CNTs) are synthesized by structural engineering of the zeolitic imidazolate framework (ZIF-67) upon treatment with dicyandiamide (DCD). A unique morphology and promising electrochemical performance are shown by the Co atoms immobilized CNTs. The electrocatalyst remarkably exhibits a highly positive onset potential of 0.99 V and half-wave potential of 0.86 V, both even more positive than the commercial Pt/C catalyst, and the current density is also greater than that of the Pt/C catalyst in alkaline media. A decent performance is observed in acidic media also. The electrocatalyst is extraordinarily stable to harsh environments. A promising performance for the oxygen evolution reaction (OER) is demonstrated by the electrocatalyst, while for bifunctional electrocatalysis a small overvoltage of 0.78 V is observed with onset potential at the lower overpotential of 300 mV announcing the advantage of its usage for practical energy conversion and storage systems. ...

The first example of hydrogen evolution reactivity (HER) of lanthanide-functionalized Keggin-based polyoxotungstates under photochemical and electrochemical conditions is reported. The HER activity under homogeneous, visible light-driven conditions and under heterogeneous, electrochemical conditions depends on the type of lanthanide functionalization, so that a new class of model HER catalysts for systematic reactivity studies is now accessible.

Electromicrobial conversion of carbon dioxide is a promising alternative to the direct transfer of CO2 into biomass by using bacteria that consume hydrogen and CO2 for living. The efficiency of such a hybrid system strongly depends on the electrocatalyst used for hydrogen production. Here we evidence that a mixed noble metal free Co/Cu-containing polyoxometalate/Carbon Cloth (Cu6Co7/CC) hybrid possesses excellent activity as a water splitting pre-electrocatalyst at neutral pH, with Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) overpotentials of 390 mV and 500 mV at 10 mA cm−2 and Tafel slopes of 96 mV dec−1 and 147 mV dec−1, respectively. The nature of the catalysts involved for both the oxidation and reduction processes has been investigated. The long-term activity of the electrodes is also demonstrated. A negligible amount of H2O2 is produced during the electrolysis process. CO2 fixation with wild-type R. eutropha and the biocompatible Cu6Co7/CC precatalyst as both anode and cathode materials has been tested. The hydrogen produced on the cathode is consumed by the bacteria for living and growth with more than 50% of input electrical energy transferred into biomass. The solar-to-biomass efficiency ηSCE can reach 9.9 ± 0.5% in a 6-day experiment, almost 10 times higher than those of natural plants, showing the high performance of this Cu6Co7/CC/R. eutropha system.

A series of carbonaceous-supported precious-metal-free polyoxometalate (POM)-based composites which can be easily synthesized on a large scale was shown to act as efficient cathode materials for the oxygen reduction reaction (ORR) in neutral or basic media via a four-electron mechanism with high durability. Moreover, exploiting the versatility of the considered system, its activity was optimized by the judicious choice of the 3d metals incorporated in the {(PW9)2M7} (M = Co, Ni) POM core, the POM counterions and the support (thermalized triazine-based frameworks (TTFs), fluorine-doped TTF (TTF-F), reduced graphene oxide, or carbon Vulcan XC-72. In particular, for {(PW9)2Ni7}/{Cu(ethylenediamine)2}/TTF-F, the overpotential required to drive the ORR compared well with those of Pt/C. This outstanding ORR electrocatalytic activity is linked with two synergistic effects due to the binary combination of the Cu and Ni centers and the strong interaction between the POM molecules and the porous and highly conducti...

Earth‐abundant transition‐metal‐based catalysts for electrochemical water splitting are critical for sustainable energy schemes. In this work, we use a rational design method for the synthesis of ultrasmall and highly dispersed bimetallic CoMo carbide/oxide particles deposited on graphene oxide. Thermal conversion of the molecular precursors [H3PMo12O40], Co(OAc)2 ⋅4 H2O and melamine in the presence of graphene oxide gives the mixed carbide/oxide (Co6Mo6C2/Co2Mo3O8) nanoparticle composite deposited on highly dispersed, N,P‐doped carbon. The resulting composite shows outstanding electrocatalytic water‐splitting activity for both the oxygen evolution and hydrogen evolution reaction, and superior performance to reference samples including commercial 20 % Pt/C & IrO2. Electrochemical and other materials analyses indicate that Co6Mo6C2 is the main active phase in the composite, and the N,P‐doping of the carbon matrix increases the catalytic activity. The facile design could in principle be extended to multiple bimetallic catalyst classes by tuning of the molecular metal oxide precursor., A rational bottom‐up design method gives access to bimetallic metal carbide/oxide nanoparticles deposited on N,P‐doped carbon matrices. The resulting composites show outstanding electrochemical reactivity for oxygen and hydrogen evolution and allow the assembly of an overall water‐splitting device (see figure).

In situ monitoring of hydrogen peroxide (H2 O2 ) during its production process is needed. Here, an electrochemical H2 O2 sensor with a wide linear current response range (concentration: 5 × 10-8 to 5 × 10-2 m), a low detection limit (32.4 × 10-9 m), and a high sensitivity (568.47 µA mm-1 cm-2 ) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co-Nx moieties anchored on nitrogen doped carbon nanotube arrays (Co-N/CNT), which is obtained through the pyrolysis of the sandwich-like urea@ZIF-67 complex. More cobalt nanoparticles and atomic Co-Nx as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen-printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H2 O2 produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields.

The rapid development of renewable-energy technologies such as water splitting, rechargeable metal-air batteries, and fuel cells requires highly efficient electrocatalysts capable of the oxygen-reduction reaction (ORR) and the oxygen-evolution reaction (OER). Herein, we report a facile sonication-driven synthesis to deposit the molecular manganese vanadium oxide precursor [Mn4 V4 O17 (OAc)3 ]3- on multiwalled carbon nanotubes (MWCNTs). Thermal conversion of this composite at 900 °C gives nanostructured manganese vanadium oxides/carbides, which are stably linked to the MWCNTs. The resulting composites show excellent electrochemical reactivity for ORR and OER, and significant reactivity enhancements compared with the precursors and a Pt/C reference are reported. Notably, even under harsh acidic conditions, long-term OER activity at low overpotential is reported. In addition, we report exceptional activity of the composites for the industrially important Cl2 evolution from an aqueous HCl electrolyte. The new composite material shows how molecular deposition routes leading to highly active and stable multifunctional electrocatalysts can be developed. The facile design could in principle be extended to multiple catalyst classes by tuning of the molecular metal oxide precursor employed.

Single atom catalysts—SACs—have received intense interest in sustainable energy research due to their enormous application potential and broad catalytic scope. In particular, SACs anchored on molecular metal oxides—polyoxometalates (POMs)—offer unrivalled possibilities as models to understand the function of these complex systems on the atomic level. Research questions which are difficult to address for classical heterogeneous SACs can be addressed by experiment and theory using POM-SACs as prototype catalysts. This review reviews the emerging field of POM-SAC research with a focus on fundamental properties and their application in energy conversion and storage technologies including water splitting, CO/CO2- as well as N2-activation. Current limitations of the field are identified and possible routes to overcome these are described. Future areas of development, including polyoxometalate-single-site catalysts, are highlighted, and critically assessed to enable the community to develop this fast-moving field further.

A highly efficient catalyst of graphene-supported mixed-valent Mn16-containing polyoxometalate is reported here by electrochemical strategy. The modified electrode with the catalyst exhibits an excellent electrocatalytic performance for water oxidation, which will contribute to the development of highly efficient catalysts for oxygen evolution. Keywords: Water oxidation, Polyoxometalates, Graphene, Electrocatalysis

The two 16-manganese-containing, Keggin-based 36-tungsto-4-silicates [Mn(III)10Mn(II)6O6(OH)6(PO4)4(A-α-SiW9O34)4](28-) (1) and [Mn(III)4Mn(II)12(OH)12(PO4)4(A-α-SiW9O34)4](28-) (2) have been prepared by reaction of the trilacunary Keggin precursor [A-α-SiW9O34](10-) with either Mn(OOCCH3)3·2H2O (for 1) or MnCl2·4H2O (for 2), in aqueous phosphate solution at pH 9. Polyanions 1 and 2 comprise mixed-valent, cationic {Mn(III)10Mn(II)6O6(OH)6}(24+) and {Mn(III)4Mn(II)12(OH)12}(24+) cores, respectively, encapsulated by four phosphate groups and four {SiW9} units in a tetrahedral fashion. Both polyanions were structurally and compositionally characterized by single-crystal XRD, IR, thermogravimetric analysis, and X-ray absorption spectroscopy. Furthermore, studies were performed probing the magnetic, electrochemical, oxidation catalytic, and Li-ion battery performance of 1 and 2.

The electrochemical oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are two critical processes for energy conversion technologies, including water electrolysis, fuel cells, and metal-air batteries. For technological implementation, both reactions require highly active and stable electrocatalysts. Here, we report the simultaneous functionalization of carbon nanotubes with bimetallic manganese-vanadium OER/ORR catalytic sites, and nitrogen/sulfur atoms to increase electrical conductivity. A bottom-up fabrication route using polyoxometalate metal precursors enables facile and scalable deposition of bimetallic catalysts on the carbon nanotubes. Electrocatalytic OER/ORR studies show the high activity and stability of the composite under alkaline aqueous conditions, and comparable performance to commercial Pt/C (20 wt.%) was observed. Initial mechanistic analyses shed light on the effects of the bimetallic functionalization as well as the N/S-doping of the carbon nanotubes. In future, the use of heterometallic polyoxometalate precursors could allow the variation of metal types and atomic ratios, which could lead to well-defined bimetallic composites for various electrochemical processes.

The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are key catalytic processes for sustainable energy technologies, such as water electrolysis or fuel cells. Here, a novel metal oxide-nanostructured carbon composite is reported, which acts as OER and ORR electrocatalyst under technologically relevant conditions. A facile synthetic process allows the deposition of a molecular manganese vanadium oxide precursor, [Mn4V4O17(OAc)3]3-, on reduced graphene oxide. Simultaneously, the precursor is converted into insoluble nanostructured solid-state Mn-V-oxide catalysts. Control of the synthetic conditions allows tuning of the electrocatalytic properties of the composites, leading to excellent and stable electrochemical reactivity. The electrocatalytic ORR and OER activity was evaluated in alkaline aqueous electrolyte and showed performance comparable with commercial Pt/C electrocatalysts. The study thus demonstrates how polyoxometalate precursors based on earth-abundant elements can be deposited on nanostructured carbon to give high-performance OER/ORR catalysts for alkaline water electrolysis. A new class of composite catalysts can in future be accessed by a facile fabrication route.

A beneficial "microenvironment effect" on the efficiency of confined electrocatalysts is predicted by theory. However, examples of its experimental confirmation are scarce for catalysts based on polyoxometalates for the hydrogen evolution reaction (HER). For this purpose, the cyclic 48-tungsto-8-phosphate [H7P8W48O184](33) (P8W48) was fixed in a 3D configuration on reduced graphene oxide sheets (rGO) to boost its HER activity. The HRTEM imaging and the solid state P-31 NMR spectrum of P8W48/rGO reveal a strong interaction between individual P8W48 and transparent rGO sheets. The calculation of the interaction between P8W48 and graphene (G) sheets is difficult to perform within a reasonable period of time because of the large size and very high overall negative charge of P8W48. However, as P8W48 is symmetrical, a quarter of its structure [H2P2W12O48](12-) (P2W12) was extracted as a DFT calculation model. As P8W48 in P8W48/rGO is neutral, due to surrounding counter cations, the calculation model P2W12 is neutral with protons considering the affordable computational time. The adsorption energy for P2W12 on G (-1.55 eV) and the charge transfer between P2W12 and G (0.66 vertical bar e vertical bar) indicate that a strong interaction between P2W12 and G sheets exists. Kinetic studies show that the P8W48/rGO hybrids display excellent HER activity in acid, further confirmed by reproducible generation of hydrogen with quantitative faradaic yield and a high turnover frequency (11 s(-1) at 295 mV overpotential) for a noble metal-free electrocatalyst. Importantly, the overpotentials required for the HER compare well with those of the commercial Pt/C (20 wt% Pt), which indicates that P8W48/rGO is a promising cheap HER electrocatalyst. We demonstrate here the most convincing experimental evidence of the "microenvironment effect" on HER electrocatalysis by a polyoxometalate.

The commercialization of fuel cells and metal–air batteries can only be realized if expensive and scarce platinum-based catalysts are replaced by lower cost, efficient, and durable catalysts for the oxygen reduction reaction (ORR). Along with intensive research efforts in developing low-cost, metal-free catalysts to replace platinum-based catalysts, heteroatom doped graphitic carbon materials (especially graphene and carbon nanotubes) have been demonstrated to show superior ORR performance. However, graphdiyne, another member of the carbon family, has not been completely studied as an electrocatalyst for the ORR. We demonstrate here that nitrogen and fluorine co-doped, metal-free graphdiyne exhibits comparable electrocatalytic activity to commercial Pt/C both in half-cell and full-cell (primary Zn–air battery) tests, regarding its onset potential and limiting current density. Moreover, the new catalyst has better stability, as well as a higher tolerance to methanol crossover and CO poisoning effects, than the commercial Pt/C.

A new type of flavone-based fluorescent probe (DMAF) capable of cysteine (Cys)/homocysteine (Hcy) sensing with high selectivity over other amino acids was developed. Such type of probe undergoes Cys/Hcy-mediated cyclization reaction with the involvement of its aldehyde group, which suppresses of the photoinduced electron transfer (PET) process of the probe molecule and consequently leads to the enhancement of fluorescence emission upon excitation using visible light. The formation of product of the Cys/Hcy-mediated cyclization reaction was confirmed and the preliminary fluorescence imaging experiments revealed the biocompatibility of the as-prepared probe and validated its practicability for intracellular Cys/Hcy sensing.

Ternary Ag nanoparticles (NPs)@polyoxometalate (POM)/reduced graphene oxide (rGO) nanohybrids were prepared by a facile photoreduction method, using POM as the photocatalyst, reducing and bridging molecules. The structure of the nanohybrids was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy, etc. Most importantly, both the rotating disk electrode and rotating ring-disk electrode tests indicated that the Ag NPs@POM/rGO nanohybrids exhibited excellent electrocatalytic activity towards oxygen reduction reaction via a direct four-electron transfer pathway due to the synergistic effect of Ag NPs and rGO.

The Co-7(AlePy)(2) polyoxometalate, which encloses a {(PW9)(2)Co-7(II)} core covalently bound to two free aminopyridine groups through bisphosphonate ligands (AlePy), has been isolated. It can be used as a precursor, allowing the synthesis of heterometallic hybrid compounds, as illustrated by the characterization of cobalt/zinc (Co-7(AlePyZn)(2)), cobalt/palladium (Co-7(AlePyPd)(2)), and cobalt/platinum (Co-7(AlePyPt)(2)) species. A composite based on the water-insoluble precious metal-free Co-7(AlePyZn)(2) compound and the low-cost carbon material Vulcan XC-72 has been selected as a cathode material (Co7Zn/C) for oxygen reduction reaction studies. The electrocatalytic performances of the Co7Zn/C hybrids were assessed at neutral and basic pH, showing that Co7Zn/C exhibits high selectivity for the four-electron reduction of O-2. Moreover, its durability is superior to that of a commercial Pt/C catalyst with 20% loading. Also, comparative studies performed in the presence of methanol have indicated that Co7Zn/C has a much better tolerance to the crossover effect than Pt/C. Altogether, these results indicate for the first time that, even in neutral media, polyoxometalate/carbon composites can represent low-cost oxygen reduction catalysts that can function stably, for a long time, and with high performance.

An anthranol derivative (DTDDP) and an anthraquinone derivative diastereomer (DDDP) without typical donor–acceptor (D–A) structural features were synthesized from 1,4-diaminoanthraquinone via a one-step reaction. The absorption and fluorescence emission properties of DTDDP and DDDP were investigated in common organic solvents with different polarity. In spite of a lack of apparent D–A structure, DTDDP exhibited apparent solvatochromic fluorescence emission with shift >80 nm in aprotic media. The linear correlation of the Stokes shift of DTDDP in a Lippert–Mataga plot was observed, and the change in the dipole moment of DTDDP upon excitation, 10.7 D, was determined. Time-dependent density functional theory (TDDFT) calculation confirmed the marked hole–electron separation of the excited DTDDP molecule as compared to that of the excited DDDP molecule. The experimental results and the theoretical calculation revealed the excited-state intramolecular charge-transfer nature of the emitting state of DTDDP molecu...

The green, facile, electrochemical-reduction-assisted assembly of ternary Ag nanoparticles (NPs)@polyoxometalate (POM)/reduced graphene oxide (rGO) is reported. The POM served as an electrocatalyst and bridging molecule. Characterization using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman and FT-IR spectroscopy analysis, etc., was performed and verified the structure of the prepared nanohybrids of Ag NPs@POM/rGO. The density and size of the Ag NPs on the rGO can be simply tuned by changing the concentration of Ag+. Most importantly, it is interesting to find that the ternary Ag NPs@POM/rGO nanohybrids showed much better electrocatalytic activities towards the oxygen reduction reaction than binary Ag NPs@POM and POM/rGO nanohybrids, and a direct four-electron transfer pathway was observed because of the synergistic effect of the Ag NPs and rGO. The electrocatalytic performance of Ag NPs@POM/rGO depended on the loading amount of Ag NPs, and 30% Ag NPs@POM/rGO showed the best electrocatalytic performance.

International audience; The application of nanohybrids based on polyoxomolybdates, reduced graphene oxide (rGO) and/or metal nanoparticles (NPs) high-performance electrode materials in electrocatalysis and energy storage devices is promising but still limited due to the complexity and the cost of the synthesis. Here we introduce a simple polyoxomolybdate, [Mo V 4O8(OH)2(H2O)2(C4O4)2] 2-(MoS), as reducing and stabilizing agent for the facile and one-pot syntheses of large quantity of highly stable MoS/rGO and MoS/Au NPs nanohybrids in aqueous solution without any catalyst or toxic co-solvent. They were characterized by various physical techniques and electrochemistry which confirm strong interaction between MoS and rGO sheets. We also used DFT calculations to investigate the affinity between MoS or its neutral form with graphene. The adsorption energy for the most stable configuration is-1.97 eV, indicating a strong adsorption process of MoS, which can also be confirmed by the distance (3.04 Å) and the charge transfer (0.86 e) between MoS and graphene. These observations are also consistent with the electrochemical results which underscore the excellent redox properties and high stability of MoS/rGO. Importantly, the MoS/rGO nanohybrids are excellent noble metal-free electrocatalysts for hydrogen peroxide reduction with high sensitivity, large detection range and low detection limit. Finally, the preliminary tests reveal that the electrode materials based on MoS/rGO and a low-cost carbon cloth (CC) composite MoS/rGO/CC may have a potential for an application in energy storage as performant and flexible supercapacitor, showing specific capacitance as high as 870 F g-1 at 10 mV s-1 and excellent stability after 5,000 cycles.

The bottom-up fabrication of molecular nanodevices will require precise (photo)-control over self-assembled interfacial structures. Here, the self-assembly and photopolymerization behaviors of six diacetylenic acid derivatives on highly oriented pyrolytic graphite (HOPG) surfaces are studied by using scanning tunneling microscope (STM). The van der Waals interaction among alkyl chains is the predominant driving force for determining the varied assembly structure. Diacetylenic acid derivatives with the diacetylene moiety directly connected to the carboxyl group (2,4-heptadecadiynoic acid (C17H26O2), 2,4-nonadecadiynoic acid (C19H30O2) and 2,4-heneicosadiynoic acid (C21H34O2)) assemble to form surface monolayers with lamella-like structures where the alkyl chains interdigitate. Moreover, diacetylenic acid derivatives with the diacetylene group located in the middle of the side chains and far from the carboxyl group (10,12-tricosadiynoic acid (C23H38O2), 10,12-pentacosadiynoic acid (C25H42O2) and 10,12-heptacosadiynoic acid (C27H46O2)) tend to assemble into paralleled structures with the alkyl chains adopting a tail-to-tail assembly mode. This work thus elucidates in detail the structure–function relationships for photo-modifiable self-assembled interfacial nanostructures based on diacetylenic acid.

Fuel cells and metal-air batteries will only become widely available in everyday life when the expensive platinum-based electrocatalysts used for the oxygen reduction reactions are replaced by other efficient, low-cost and stable catalysts. We report here the use of nitrogen-doped graphdiyne as a metal-free electrode with a comparable electrocatalytic activity to commercial Pt/C catalysts for the oxygen reduction reaction in alkaline fuel cells. Nitrogen-doped graphdiyne has a better stability and increased tolerance to the cross-over effect than conventional Pt/C catalysts.

The photocatalytic hydrogen (H-2) evolution with transition-metal substituted Keggin-type titanium tungstates Na-5(6)[MTiW11O39]center dot xH(2)O (abbreviated as TiW11M (M = Fe, Co, Zn)) as photocatalyst was reported. They showed good photocatalytic activities toward H-2 evolution in homogeneous systems under simulated solar light irradiation. The order of photocatalytic activity was TiW11Co approximate to TiW11Zn > TiW11Fe >> H3PW12O40 (PW12). The selected POMs showed good stability during the reactions. Karl Fischer analysis, ICPE (Inductive Coupled Plasma Emission) and FT-IR (Fourier Transform Infrared Spectroscopy) were used to confirm the composition and structure. UV-Vis absorption spectra, kinetics investigation and cyclic voltammetric characterizations were used to explain the photocatalytic results. Finally, an analogous "Z-scheme'' mechanism was proposed for the homogeneous systems toward photocatalytic H-2 evolution under simulated solar light irradiation.

rGO-CdS-H2W12 nanocomposite film was successfully fabricated by a layer-by-layer self-assembly method. The composite film was characterized by techniques such as UV-Vis spectra, XPS, and AFM. The composite film showed high photoelectronic response under the illumination of sunlight. Both current-voltage curves and photocurrent transient measurements demonstrated that the photocurrent response of the rGO-CdS-H2W12 composite film was enhanced five-fold compared with CdS film. This can be attributed to the photoinduced electron transfer between CdS, H2W12 and rGO, which promotes the charge separation efficiency of CdS. The introduction of GO enhanced the charge separation and transportation. More importantly, various pollutants can be treated as electron donors, and can thus be degraded and produce hydrogen at the same time, at a low bias voltage under the irradiation of solar light.