Photocatalytic Three-Component Reaction for the Synthesis of Multifunctional Diaryl Sulfides.

A photocatalytic three-component reaction of a nitroarene, a thiophenol, and a ketone for the synthesis of multifunctional diaryl sulfides was reported using a nitro group as the nitrogen source and thiophenol as the sulfur source. Thiophenol also serves as a proton donor to reduce nitroarene to arylamine as a key intermediate for the formation of C-N and C-S bonds. Good functional group tolerance and mild reaction conditions make this method have practical synthetic value for diversified multifunctional diaryl sulfides.

High-energy-density flexible graphene-based supercapacitors enabled by atypical hydroquinone dimethyl ether.

Supercapacitor is an electrochemical energy-storage technology that can meet the green and sustainable energy needs of the future. However, a low energy density was a bottleneck that limited its practical application. To overcome this, we developed a heterojunction system composed of two-dimensional (2D) graphene and hydroquinone dimethyl ether- an atypical redox-active aromatic ether. This heterojunction displayed a large specific capacitance (Cs) of 523 F g-1 at 1.0 A g-1, as well as good rate capability and cycling stability. When assembled in symmetric and asymmetric two-electrode configuration, respectively, supercapacitors can work in voltage windows of 0 âˆ¼ 1.0 V and 0 âˆ¼ 1.6 V, accordingly, and exhibited attractive capacitive characteristics. The best device can deliver an energy density of 32.4 Wh Kg-1 and a power density of 8000 W Kg-1, and suffered a small capacitance degradation. Additionally, the device showed low self-discharge and leakage current behaviors during long time. This strategy may inspire exploration of aromatic ether electrochemistry and pave a way to develop electrical double-layer capacitance (EDLC)/pseudocapacitance heterojunctions to boost the critical energy density.

Lewis Acid-Induced Reversible Disproportionation of TEMPO Enables Aqueous Aluminum Radical Batteries.

Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO), are typical organic electrode materials featuring high redox potentials and fast electrochemical kinetics and have been widely used as cathode materials in multivalent metal-ion batteries. However, TEMPO and its derivatives have not been used in emerging rechargeable aluminum-ion batteries (AIBs) due to the known disproportionation and possible degradation of nitroxide radicals in acidic conditions. In this study, the (electro)chemical behavior of TEMPO is examined in organic and aqueous Lewis acid electrolytes. Through in situ (electro)chemical characterizations and theoretical computation, we reveal for the first time an irreversible disproportionation of TEMPO in organic Al(OTf)3 electrolytes that can be steered to a reversible process when switching to an aqueous media. In the latter case, a fast hydrolysis and ligand exchange between [Al(OTf)3TEMPO]- anion and water enable the overall reversible electrochemical redox reaction of TEMPO. These findings lead to the first design of radical polymer aqueous AIBs that are fire-retardant and air-stable, delivering a stable voltage output of 1.25 V and a capacity of 110 mAh g-1 over 800 cycles with 0.028% loss per cycle. This work demonstrates the promise of using nonconjugated organic electroactive materials for cost-effective and safe AIBs that currently rely on conjugated organic molecules.

High-performance reduced graphene oxide supercapacitors enabled by simple amino hydroquinone dimethylether.

Reduced graphene oxide (rGO) supercapacitors usually feature poor capacitive characteristics. In the current work, coupling of the simple, nonclassical redox molecule amino hydroquinone dimethylether with rGO was found to boost the rGO capacitance to 523 F g-1. The assembled device exhibited an energy density of 143 Wh kg-1 and excellent rate capability and cyclability.

Engineering electronic structure of graphene to boost Lithium-Storage performances.

Organic functionalization of graphene framework was an effective means used to boost the storage performances of lithium, but it lacked a universal strategic guideline for introducing functional groups (electron-withdrawing and electron-donating modules are overall classified). It mainly entailed designing and synthesizing graphene derivatives, in which the interference functional groups were necessarily excluded. To this end, a unique synthetic methodology based on graphite reduction cascaded by electrophilic reaction was developed. The electron-withdrawing-type groups (Br; trifluoroacetyl: TFAc) and electron-donating-type counterparts (butyl: Bu; 4-methoxyphenyl: 4-MeOPh) were readily attached to graphene sheets at a comparable functionalization degree. As the electron density of carbon skeleton was enriched by electron-donating modules, particularly for Bu units, the lithium-storage capacity, rate capability and cyclability were appreciably boosted. For example, they had 512 and 286 mA h g-1 at 0.5C and 2C, respectively; and 88 % of capacity retention after 500 cycles at 1C.

Structure-Performance relationship guided design and strategic synthesis of lithiated oxa-graphene for high lithium storage.

Graphene derivative materials are widely used as anode component in lithium-ion batteries. However, there is still a lack of reliable and foresighted guides helpful for designing high-performance graphene-based electrode materials. To this end, we strategically chose challenging graphite fluoride as starting material for the derivatization of graphene in order to exclude interference factors. As a result, graphene framework was functionalized with oxygen-containing carboxylate and sulfonate groups and oxygen-free aniline units at a similar functionalization degree. Due to the strong effect of lithiation, out-of-plane p-aminobenzoic acid blocks boosted the lithium-storage capacity of graphene matrix to 636 mAh g-1 at 0.1 A/g, and sulfanilic acid blocks maximized this value to 873 mAh g-1. Sadly, oxygen-free aniline functionalized graphene material only delivered a specific capacity of 88 mAh g-1. Meanwhile, spatial lithiated carboxylate and sulfonate units endowed graphene framework with better rate capability and cycling stability. Such a structure-performance relationship established herein was beneficial for the design and preparation of high-performance graphene derivative electrode materials.

Ultrasimple air-annealed pure graphene oxide film for high-performance supercapacitors.

Realizing both high gravimetric and volumetric specific capacitances (noted as CW and CV, respectively) is an essential prerequisite for the next-generation, high performance supercapacitors. However, the need of electronic/ionic transport for electrochemical reactions causes a "trade-off" between compacted density and capacitance of electrode, thereby impairing gravimetric or volumetric specific capacitances. Herein, we report a high-performance, film-based supercapacitor via a thermal reduction of graphene oxide (GO) in air. The reduced, layer-structured graphene film ensures high electrode density and high electron conductivity, while the hierarchical channels generated from reduction-induced gas releasing process offer sufficient ion transport pathways. Note that the resultant graphene film is employed directly as electrodes without using any additives (binders and conductive agents). As expected, the as-prepared electrodes perform particularly well in both CW (420F g-1) and CV (360F cm-3) at a current density of 0.5 A g-1. Even at an ultrahigh current density of 50 A g-1, CW and CV maintain in 220F g-1 and 189F cm-3, respectively. Furthermore, the corresponding symmetric two-electrode supercapacitor achieves both high gravimetric energy density of 54 W h kg-1 and high gravimetric power density of 1080 W kg-1, corresponding to volumetric energy density of 46 W h L-1 and volumetric power density of 917 W L-1.

High-Performance Flexible Asymmetric Supercapacitor Paired with Indanthrone@Graphene Heterojunctions and MXene Electrodes.

The energy density formula illuminated that widening the voltage window and maximizing capacitance are effective strategies to boost the energy density of supercapacitors. However, aqueous electrolyte-based devices generally afford a voltage window less than 1.2 V in view of water electrolysis, and chemically converted graphene yields mediocre capacitance. Herein, multi-electron redox-reversible, structurally stable indanthrone (IDT) π-backbones were rationally coupled with the reduced graphene oxide (rGO) framework to form IDT@rGO molecular heterojunctions. Such conductive agent- and binder-free film electrodes delivered a maximized capacitance of up to 345 F g-1 in a potential range of -0.2 to 1.0 V. The partner film electrode-Ti3C2Tx MXene which worked in the negative potential range of -0.1 to -0.6 V-afforded a capacitance as large as 769 F g-1. Thanks to the perfect complementary potentials of the IDT@rGO heterojunction positive electrode and Ti3C2Tx MXene negative partner, the polyvinyl alcohol/H2SO4 hydrogel electrolyte-based flexible asymmetric supercapacitor delivered an enlarged voltage window of 1.6 V and an impressive energy density of 17 W h kg-1 at a high power density of 8 kW kg-1, plus remarkable rate capability and cycling life (capacitance retention of ∼90% after 10000 cycles) as well as exceptional flexibility and bendability.

Transfunctionalization of graphite fluoride engineered polyaniline grafting to graphene for High-Performance flexible supercapacitors.

Low energy density is the major obstacle for the practical all-solid-state supercapacitors, which may be raised by the combination of the pseudocapacitance with the electrochemical double-layer capacitance. Although graphene and polyaniline have been demonstrated two effective materials, the synthetic route of graphene and their hybrid mode largely dictated the capacitive performances and cyclability of graphene/polyaniline nanocomposites. Herein, we employed commercial graphite fluoride as the precursor to obtain graphene with a well-preserved carbon lattice. After graphite fluoride functionalization by p-phenylenediamine (pPDA) and in situ oxidative polymerization of anilines, polyaniline (PANI) chains were covalently attached to graphene framework through pPDA bridges. Multiple characterizations were performed to confirm the covalent binding mode between graphene scaffolds and PANI partners, and electrochemical tests unraveled the as-prepared G-pPDA-PANI triads delivered a gravimetric capacitance as high as 638F g-1 and a further amplified volumetric capacitance (up to 759F cm-3). The bendable all-solid-state supercapacitors yielded an encouraging energy density of over 18 W   h L-1 at a power density high to 5,950 W L-1, while exhibiting an exceptional rate capability, cycling stability and mechanical flexibility.

Comparative performance of FAS equation and Asian modified CKD-EPI in the determination of GFR in Chinese patients with CKD with the 99mTc-DTPA plasma clearance as the reference method.

BACKGROUND: Glomerular filtration rate (GFR) is a useful index in many clinical conditions. However, very few studies have assessed the performance of full age spectrum (FAS) equation and the Asian modified Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation in the approximation of GFR in Chinese patients with chronic kidney disease. OBJECTIVE: This study aimed to compare the diagnostic performance of the above two creatinine-based equations. METHODS: A well designed single-center cross-sectional study was performed and the GFR was determined by 3 methods separately in the same day: technetium-99m-diethylene triamine pentaacetic acid (99mTc-DTPA) dual plasma sample clearance method (mGFR); FAS equation method; Asian modified CKD-EPI equation method. The gold standard method was the mGFR. Equations performance criteria considered correlation coefficient, bias, precision, accuracy and the ability to detect the mGFR less than 60ml/min/1.73m2. RESULTS: A total of 160 patients were enrolled. The diagnostic performance of FAS showed no significant difference in the correlation coefficient (0.89 vs 0.89), precision (15.9 vs 16.1ml/min/1.73m2), accuracy (75.0% vs 76.3%) and the ability to detect the mGFR less than 60ml/min/1.73m2 (0.94 vs 0.94) compared with the Asian modified CKD-EPI equation in all participants. The FAS showed a negative bias, while the new CKD-EPI equation showed a positive bias (-1.20 vs 1.30ml/min/1.73m2, P<0.001). However, they were all near to zero. In the mGFR<60ml/min/1.73m2 subgroup and mGFR>60ml/min/1.73m2 subgroup were consistent with that in the whole cohort. The precision and accuracy decreased when GFR>60ml/min/1.73m2 in both equations. CONCLUSIONS: The FAS equation and the Asian modified CKD-EPI equation had similar performance in determining the glomerular filtration rate in the Chinese patients with chronic kidney disease. Both the FAS equation and Asian modified CKD-EPI can be a satisfactory method and may be the most suitable creatinine-based equation.

Comparative performance of FAS equation and Asian modified CKD-EPI in the determination of GFR in Chinese patients with CKD with the 99mTc-DTPA plasma clearance as the reference method.

BACKGROUND: Glomerular filtration rate (GFR) is a useful index in many clinical conditions. However, very few studies have assessed the performance of full age spectrum (FAS) equation and the Asian modified Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation in the approximation of GFR in Chinese patients with chronic kidney disease. OBJECTIVE: This study aimed to compare the diagnostic performance of the above two creatinine-based equations. METHODS: A well designed single-center cross-sectional study was performed and the GFR was determined by 3 methods separately in the same day: technetium-99m-diethylene triamine pentaacetic acid (99mTc-DTPA) dual plasma sample clearance method (mGFR); FAS equation method; Asian modified CKD-EPI equation method. The gold standard method was the mGFR. Equations performance criteria considered correlation coefficient, bias, precision, accuracy and the ability to detect the mGFR less than 60ml/min/1.73m2. RESULTS: A total of 160 patients were enrolled. The diagnostic performance of FAS showed no significant difference in the correlation coefficient (0.89 vs 0.89), precision (15.9 vs 16.1ml/min/1.73m2), accuracy (75.0% vs 76.3%) and the ability to detect the mGFR less than 60ml/min/1.73m2 (0.94 vs 0.94) compared with the Asian modified CKD-EPI equation in all participants. The FAS showed a negative bias, while the new CKD-EPI equation showed a positive bias (-1.20 vs 1.30ml/min/1.73m2, P<0.001). However, they were all near to zero. In the mGFR<60ml/min/1.73m2 subgroup and mGFR>60ml/min/1.73m2 subgroup were consistent with that in the whole cohort. The precision and accuracy decreased when GFR>60ml/min/1.73m2 in both equations. CONCLUSIONS: The FAS equation and the Asian modified CKD-EPI equation had similar performance in determining the glomerular filtration rate in the Chinese patients with chronic kidney disease. Both the FAS equation and Asian modified CKD-EPI can be a satisfactory method and may be the most suitable creatinine-based equation.

[Acupuncture combined with cranial electrotherapy stimulation on generalized anxiety disorder: a randomized controlled trial].

OBJECTIVE: To observe the therapeutic effect of acupuncture combined with cranial electrotherapy stimulation (CES) on generalized anxiety disorder (GAD). METHODS: A total of 200 patients with GAD were randomized into an acupuncture+CES group, an acupuncture group, a CES group and a medication group, 50 cases in each one. In the medication group, patients were treated with tandospirone citrate tablet orally, 10 mg after breakfast, lunch and dinner respectively. In the CES group, CES was adopted by SCS brain electromedical instrument, 60 min each time, once a day. In the acupuncture group, acupuncture was applied to Baihui (GV 20), Sishencong (EX-HN 1), Yintang (GV 29), Shenting (GV 24), etc., 30 min each time, once a day. In the acupuncture+CES group, CES was adopted before acupuncture. Treatment of sixty days was required in the 4 groups. Before and after treatment, the scores of Hamilton anxiety scale (HAMA), World Health Organization's quality of life questionnaire-brief version (WHOQOL-BREF) and treatment emergent symptom scale (TESS) were observed, the clinical effect was evaluated, and the relapse of anxiety during follow-up of 1 year after treatment was recorded in the 4 groups. RESULTS: Compared before treatment, the scores of HAMA after treatment were decreased (P<0.05), the scores of WHOQOL- BREF after treatment were increased in the 4 groups (P<0.05), and the improvements of above scores in the acupuncture+CES group were greater than the other 3 groups (P<0.05). The score of TESS after treatment and the relapse rate of 1-year follow-up in the medication group were higher than those in the other 3 groups (P<0.05). The total effective rate in the acupuncture+CES group were superior to the other 3 groups (P<0.05). CONCLUSION: Acupuncture combined with CES can effectively relieve the symptoms in patients with GAD, improve the quality of life, reduce the occurrence of adverse reactions and the relapse rate, and its clinical effect is obviously superior to the western medication, the simple application of acupuncture or CES.

Sulfanilic Acid Pending on a Graphene Scaffold: Novel, Efficient Synthesis and Much Enhanced Polymer Solar Cell Efficiency and Stability Using It as a Hole Extraction Layer.

In this contribution, we describe a novel, facile, and scalable methodology for high degree functionalization toward graphene by the reaction between bulk graphite fluoride and in situ generated amine anion. Using this, the rationally designed sulfanilic acid pending on a graphene scaffold (G-SO3H), a two-dimensional (2D) π-conjugated counterpart of poly(styrenesulfonate), is available. Combined reliable characterizations demonstrate that a very large quantity of sulfanilic blocks are linked to graphene through the foreseen substitution of carbon-fluorine units and an unexpected reductive defluorination simultaneously proceeds during the one-step reaction, endowing the resultant G-SO3H with splendid dispersity in various solvents and film-forming property via the former, and with recovered 2D π-conjugation via the latter. Besides, the work function of G-SO3H lies at -4.8 eV, well matched with the P3HT donor. Awarded with these fantastic merits, G-SO3H behaves capable in hole collection and transport, indicated by the enhanced device efficiency and stability of polymer solar cells (PSCs) based on intensively studied P3HT:PCBM blends as an active layer. In particular, comparison with conventional poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) and recently rising and shining graphene oxide, G-SO3H outperforms above 17 and 24%, respectively, in efficiency. More impressively, when these three unencapsulated devices are placed in a N2-filled glovebox at around 25 °C for 7 weeks, or subject to thermal treatment at 150 °C for 6 h also in N2 atmosphere, or even rudely exposed to indoor air, G-SO3H-based PSCs exhibit the best stability. These findings enable G-SO3H to be a strongly competitive alternative of the existing hole extraction materials for PSC real-life applications.

Shape-controllable and versatile synthesis of copper nanocrystals with amino acids as capping agents.

Thanks to their outstanding properties and a wide range of promising applications, the development of a versatile and convenient preparation method for metallic copper nanocrystals with controllable shape is of primary significance. Different from the literature that utilized a capping agent bearing only one kind of Cu binding functionality, either an amino or a carboxylic unit, for their preparation and shape control, this contribution reports a convenient method to engage both amino and carboxylic binding units at the same time. In this method, natural amino acids have been chosen as capping agents and demonstrated their versatile capabilities for the preparation of both Cu nanoparticles and nanowires. Detailed X-ray photoelectron spectroscopy revealed that the binding mode between amino acids and the Cu surface is highly dependent on their chemical structures. Interestingly, the produced Cu nanocrystals, exhibited an extraordinarily excellent anti-oxidation power. Furthermore, it was found that the multiple functionalities of amino acids not only have a great impact on the properties of their capped nanocrystals, such as solvent dispersibility, but also provide a convenient route for their further modification and functionalization.