Acridinium benzoates for ratiometric fluorescence imaging of cellular viscosity.

A series of fluorescent molecular rotors, acridinium benzoates (Acr-A,B,C,D), were designed for ratiometrically monitoring cellular viscosity. High sensitivity to viscosity was observed in probe Acr-A with an insignificant steric effect in the acridinium nitrogen. Acr-A was employed to distinguish cancer cells from normal cells and track the dynamics of viscosity during cellular apoptosis.

Acridinium Benzoates for Ratiometric Fluorescence Imaging.

Acridinium benzoate was developed as a unique ICT-based fluorescent scaffold for both ratiometric and turn-on fluorescence imaging through decaging of the phenolic hydroxyl groups. Two fluorescent probes, Acr1-H2 O2 and Acr1-ß-gal, were developed for the fluorescence imaging of H2 O2 and ß-galactosidase in vivo.

Origin of the Ability of α-Fe2 O3 Mesopores to Activate C-H Bonds in Methane.

Methane is a most abundant and inexpensive hydrocarbon feedstock for the production of chemicals and fuels. However, it is extremely difficult to directly convert methane to higher hydrocarbons because the C-H bonds in methane are the most stable C-H bonds of all hydrocarbons. The activation of the C-H bonds in methane by using an efficient and mild route remains a daunting challenge. Here, we show that the inner surface structures of the pore walls in mesoporous α-Fe2 O3 possess excellent catalytic performance for methane activation and convert C-H bonds into the C-O bonds in an O2 atmosphere at 140 °C. We found that such unusual structures are mainly comprised of turbostratic ribbons and K crystal faces and have higher catalytic activity than the (110) plane. These results are without precedent in the history of catalysis chemistry and will provide a new pathway for designing and preparing highly efficient catalytic materials.

Ordered mesoporous Fe-porphyrin-like architectures as excellent cathode materials for the oxygen reduction reaction in both alkaline and acidic media.

Iron ORR: An ordered, mesoporous, Fe-porphyrin-like material was created through the nanocasting and pyrolysis of traditional Fe-N4 porphyrins. The resulting nonprecious metal electrocatalyst was used for the oxygen reduction reaction in both alkaline and acidic media.

Activated biochar derived from peanut shells as the electrode materials with excellent performance in Zinc-air battery and supercapacitance.

The use of activated biochar-based electrode derived from waste biomass in energy technologies, such as metal-air batteries and supercapacitors, is an important strategy for realizing energy and environmental sustainability in the future. Herein, peanut shells (waste biomass) were employed to prepare activated biochar materials by pyrolysis in molten KCl and heat-treatment. The effective dispersion and corrosion effects of molten salt for the pyrolysis products during pyrolysis obviously increase defects and specific surface area of the activated biochar materials. The prepared activated biochar material (PS-800-1000) by pyrolysis in molten KCl at 800 °C and heat-treatment at 1000 °C exhibits excellent catalytic activity with half-wave potential of 0.84 V vs. RHE, comparable to commercial Pt/C for oxygen reduction reaction (ORR) in 0.1 M KOH and outstanding supercapacitance performance in 6 M KOH with high specific capacitance (355 F g-1 at 0.5 A g-1), which exceeds all reported biochar derived from peanut shells. The PS-800-1000-based zinc-air battery (ZAB) displays higher peak power density (141 mW cm-2), specific capacity (767 mAh gZn-1) and cycling stability than Pt/C-based ZAB. The activated biochar prepared by pyrolysis in molten KCl and heat-treatment method from peanut shells can be a promising candidate for replacing precious metals in energy conversion/storage devices.

Covalent pendulous anthraquinone polymers coupled on graphenes for efficient capacitance storage in both alkaline and acidic media.

Novel crystalline covalent organic polymers (COPs) were constructed by reacting 1,4-diaminoanthraquinone with 1,3,5-triformylphloroglucinol or tris(4-formylphenyl)amine (TPDA or TADA). After they were covalently bonded to amine-functionalized graphene oxides, the resulting mesoporous COPs@graphene composites demonstrated efficient capacitance storage performance in both alkaline and acidic media. In particular, the as-synthesized TPDA@graphene displayed a reversible specific capacitance of 522 F g-1 in a 6.0 mol L-1 aqueous KOH electrolyte, superior to the previously reported COPs with inconspicuous capacitance storage properties in alkaline media. Its specific capacitance also reached 390 F g-1 in 2.0 mol L-1 H2SO4. The impressive capacitance storage properties of this composite can be ascribed to its unique structure with abundant pendulous anthraquinone redox groups and better electrical conductivity enhanced by the coupled graphenes.

Efficient Nitrate Reduction over Novel Covalent Ag-Salophen Polymer-Derived "Vein-Leaf-Apple"-like Ag@Carbon Structures.

Efficient electrocatalysts for nitrate reduction reaction (NO3--RR) that could selectively transfer nitrate into harmless nitrogen are required for water-denitrification treatment. The most widely used electrodes for NO3--RR including noble metals, transition metals, and their alloys still face many challenges such as lower selectivity and efficiency, high cost, and easy corrosion properties. Metallic Ag with acceptable cost possesses strong corrosion resistance in electrolysis, but its activity is often incompetent for NO3--RR. In this work, Ag nanoparticles with a lower loading content (1.99 wt %) on a nitrogen-doped carbon support was successfully used as the robust electrocatalyst for NO3--RR in a Cl--free neutral solution. This Ag@carbon catalyst exhibited an impressive electrochemical performance for NO3--RR, with a NO3--N conversion yield of 53% and a N2-N selectivity of 97% at a low electrolysis overpotential (-0.29 V vs RHE). In particular, the prepared Ag@carbon showed better stability and no secondary Ag ion pollution in electrolysis. Its impressive electrocatalytic performance was attributed to the unique "vein-leaf-apple"-like Ag@carbon structures, prepared by thermal conversion of Ag-salophen polymers@CNTs. CNTs served as veins to enhance the electron transportation in electrocatalysts. Salophen polymer-derived mesoporous N-doped carbon plates acted as leaves to concentrate NO3- from the electrolyte. Like apples on trees, Ag nanoparticles of about 10-20 nm highly dispersed on carbons selectively converted NO3--N into N2-N. It opens up a cost-acceptable and corrosion-resistant Ag-less electrocatalytic pathway for NO3--RR, and the special "vein-leaf-apple"-like Ag@carbon structure could enhance the electrolytic efficiency and N2-N selectivity for NO3--RR.

3D Graphene-Carbon Nanotube Hybrid Supported Coupled Co-MnO Nanoparticles as Highly Efficient Bifunctional Electrocatalyst for Rechargeable Zn-Air Batteries.

The development of high-efficiency and low-cost catalysts is one of the core and important issues to improve the efficiency of electrochemical reactions on electrodes, and it is also the goal we ultimately pursue in the commercialization of large-scale clean energy technologies, such as metal-air batteries. Herein, a nitrogen-doped graphene oxide (GO)-carbon nanotube (CNT) hybrid network supported coupled Co/MnO nanoparticles (Co/MnO@N-C) catalyst was prepared with a hydrothermal-pyrolysis method. The unique three-dimensional network structure of substrate allowed for the uniform dispersion of Co-MnO nanoparticles in the carbon skeleton. These characters enable the Co/MnO@N-C to possess the excellent bifunctional electrocatalysts. In alkaline electrolyte, the Co/MnO@N-C presents the outstanding oxygen evolution reaction (OER) performance comparable to the commercial RuO2 catalyst and the exceedingly good oxygen reduction reaction (ORR) activity with positive half-wave potential of 0.90 V vs. RHE outperforming commercial Pt/C (0.84 V vs. RHE) and the recently reported analogous electrocatalysts. When it is applied to homemade Zn-air batteries, such a non-noble metal electrocatalyst can deliver a better power density, specific capacity and cycling stability than mixed Pt/C and RuO2 catalyst, and exhibits a wide application prospect and great practical value.

Synthesis of cube-rod-tube triblock asymmetric nanostructures for enhanced heterogeneous catalysis.

A triblock asymmetric nanostructure composed of a core-shell Fe2O3@SiO2 cube as the head, SiO2 rod as the body and SiO2 tube as the tail is fabricated via a sequential growth process combining solution-liquid-solid and droplet soft templating mechanisms, which can be used as a nano stir bar with accelerated catalytic performance.

A three-dimensional supramolecular vanadium hydroxylamide complex: poly[di-mu2-aqua-bis(hydroxylamido)-mu3-malonato-oxidosodiumvanadium(V)].

The crystal structure of the title compound, [NaV(C3H2O4)(NH2O)2O(H2O)2], is built up of NaO6 and VO5N2 polyhedra connected through malonate bridges. The NaO6 octahedra are linked by edge sharing in the equatorial plane to form one-dimensional infinite chains. These chains are linked together by the malonate bridges to form two-dimensional layers. The distorted VO5N2 pentagonal bipyramid is grafted on to the layer by a malonate carboxylate O atom. Adjacent layers are connected through O-H...O and N-H...O hydrogen bonds to build up a three-dimensional supramolecular structure.

Sn(OH)x-assisted synthesis of mesoporous Mn-porphyrinic frameworks and their carbon derivatives for electrocatalysis.

5,10,15,20-Tetrakis (4-aminophenyl) Mn-porphyrin and 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde were combined into a new mesoporous organic framework by a Schiff-base-type reaction. Sn(OH)x helped in improving the yield of this Mn-COF. Further, S-containing dimethyl sulfoxide solvent molecules were tripped in the pores of Mn-COFs. Such heteroatoms-enriched Mn-COFs could be used to fabricate Mn-S-N-doped carbons (Mn-S-N-Cs) with abundant mesopores. In particular, Mn-Nx sites could be partly maintained and highly dispersed on the surface of Mn-S-N-Cs; impressively, Mn-N-S-C-800 could be catalyzed for oxygen electroreduction in both alkaline and acidic media. Its half-wave potential reached 0.86 V in 0.1 M KOH, with a very low yield of HO2- (4.02%) and better durability. The thermal conversion of the synthesized mesoporous porphyrinic Mn-COFs provided an efficient strategy for fabricating high-dispersion Mn-Nx sites on mesoporous S and N codoped carbons.

Pyrolytic Carbon-coated Cu-Fe Alloy Nanoparticles with High Catalytic Performance for Oxygen Electroreduction.

Well-dispersed carbon-coated or nitrogen-doped carbon-coated copper-iron alloy nanoparticles (FeCu@C or FeCu@C-N) in carbon-based supports are obtained using a bimetallic metal-organic framework (Cu/Fe-MOF-74) or a mixture of Cu/Fe-MOF-74 and melamine as sacrificial templates and an active-component precursor by using a pyrolysis method. The investigation results attest formation of Cu-Fe alloy nanoparticles. The obtained FeCu@C catalyst exhibits a catalytic activity with a half-wave potential of 0.83 V for oxygen reduction reaction (ORR) in alkaline medium, comparable to that on commercial Pt/C catalyst (0.84 V). The catalytic activity of FeCu@C-N for ORR (Ehalf-wave =0.87 V) outshines all reported analogues. The excellent performance of FeCu@C-N should be attributed to a change in the energy of the d-band center of Cu resulting from the formation of the copper-iron alloy, the interaction between alloy nanoparticles and supports and N-doping in the carbon matrix. Moreover, FeCu@C and FeCu@C-N show better electrochemical stability and methanol tolerance than commercial Pt/C and are expected to be widely used in practical applications.

Single-Composition White Light Emission from Dy3+ Doped Sr2CaWO6.

A series of Dy3+ ion doped Sr2CaWO6 phosphors with double perovskite structure were synthesized by traditional high temperature solid-state method. It was found that there is significant energy transfer between Dy3+ and the host lattice, and the intensities of emission peaks at 449 nm (blue), 499 nm (cyan), 599 nm (orange), 670 nm (red), and 766 nm (infra-red) can be changed by adjusting the concentration of dopant amount of Dy3+ ion in Sr2CaWO6. The correlated color temperature of Dy3+ ion doped Sr2CaWO6 phosphors can be tuned by adjusting the concentration of Dy3+ ion. Upon optimal doping at 1.00 mol% Dy3+, white light with chromaticity coordinate (0.34, 0.33) was emitted under excitation at 310 nm. Thus, single composition white emission is realized in Dy3+ doped Sr2CaWO6.

Construction of highly pure nanocrystalline heteropoly acid inside the channels of mesoporous material with the imprisoned hydrolyzation reaction of heteropoly acid etherate.

A novel technique was developed to prepare highly pure heteropoly acid (HPA) nanocrystals inside mesoporous SBA-15 by the imprisoned reaction of HPA etherate and water, which was utilized as a main driving force for the transportation of building-blocks. The transmission electron microscopy, X-ray diffraction, FT-IR spectrum and NMR characterizations unambiguously demonstrate that this method allows the highly pure heteropoly acid nanocrystals with intact Keggin-type structure controlled directionally self-assembly within mesopores of silica SBA-15. Such method may open up a new entry to the highly pure multicomponent nanocrystalline particles inside the cavity of the porous materials.

Electroactive Cu-P-Coupled Moieties Doped in Hierarchically Porous Carbon as Efficient Catalysts for the Oxygen-Reduction Reaction.

A porous carbon material that was co-doped with copper and phosphorus (Cu-P-C) was synthesized by the direct thermal conversion of [(Ph3 P)2 CuCl2 ] in the channels of an SBA-15 template and found to be an impressive Cu-based electrocatalyst. The prefabricated Cu-Px moieties in the starting [(Ph3 P)2 CuCl2 ] were retained during the preparation process of the catalyst. These Cu-Px active sites effectively catalyzed the oxygen-reduction reaction (ORR). Moreover, the hierarchically porous morphology of the Cu-P-C material, which demonstrated a large specific surface area, allowed for a higher density of the Cu-Px active sites, thereby facilitating mass transfer and further boosting the electrocatalytic activity of the Cu-P-C catalyst. The as-obtained catalyst exhibited surprising catalytic activity, with a halfwave potential of 0.833 V in alkaline medium, which was comparable to that of the commercial Pt/C-JM catalyst, and possessed the highest activity among the reported M-P-C catalysts for the ORR.

Covalent Porphyrin Framework-Derived Fe2P@Fe4N-Coupled Nanoparticles Embedded in N-Doped Carbons as Efficient Trifunctional Electrocatalysts.

A new porous covalent porphyrin framework (CPF) filled with triphenylphosphine was designed and synthesized using the rigid tetrakis(p-bromophenyl)porphyrin (TBPP) and 1,3,5-benzenetriboronic acid trivalent alcohol ester as building blocks. The carbonization of this special CPF has afforded coupled Fe2P and Fe4N nanoparticles embedded in N-doped carbons (Fe2P/Fe4N@N-doped carbons). This CPF serves as an "all in one" precursor of Fe, N, P, and C. The porous property and solid skeleton of the CPF endow Fe2P/Fe4N@N-doped carbons with porous structure and a high degree of graphitization. As a result, Fe2P/Fe4N@N-doped carbons exhibited highly efficient multifunctional electrocatalytic performance for water splitting and oxygen electroreduction. Typically, Fe2P/Fe4N@C-800, obtained at a heat-treatment temperature of 800 °C, showed an ORR half-wave potential of 0.80 V in alkaline media and 0.68 V in acidic media, close to that of commercial Pt/C catalysts. Fe2P/Fe4N@C-800 also displayed efficient OER and HER activities, comparable to other phosphide and nitride electrocatalysts. The coupled Fe4N and Fe2P nanoparticles embedded in carbons exert unique catalytic efficiency for water splitting and fuel cells.

Space-confined synthesis of multilayer Cu-N-doped graphene nanosheets for efficient oxygen electroreduction.

Cu-based carbon electrocatalysts for the oxygen reduction reaction are difficult to compare with the corresponding Fe- or Co-based electrocatalytic materials, owing to their insufficient catalytic activity and stability. Herein, as an impressive Cu-based electrocatalyst, a multilayer Cu-N-doped graphene sheet (Cu-N-GR) is directly synthesized by the thermal conversion of copper(ii) 2,2'-bipyridine in the confined space of lamellar montmorillonites. The open layered morphology of Cu-N-GR materials facilitated the exposure of more active centers and enhanced the flexibility and mobility of charge carriers. Combining the unique electronic properties of layered morphology and the synergistic effect of Cu and N, the obtained Cu-N-GR exhibits surprising results in terms of ORR catalytic activity, particularly in catalytic stability and methanol-tolerant properties in alkaline media.

A New Route to Organic Intercalates Consisting of Vanadium Pentoxide and Pyridines: (4-H2 N-C5 H5 NH)V2 O5.

Light at the end of the tunnel! Intercalates of pyridine and layered inorganic compounds have intrigued chemists for at least two decades, but their structure determination has always been difficult owing to a lack of suitable single crystals. The intercalate (4-H2 N-C5 H5 NH)V2 O5 has now been characterized by X-ray crystal structure analysis, and its electronic structure and magnetic properties have been studied in detail.

Preparation and visible light photocatalytic activity of Ag/TiO2/graphene nanocomposite.

Great efforts have been made to develop efficient visible light-activated photocatalysts in recent years. In this work, a new nanocomposite consisting of anatase TiO(2), Ag, and graphene was prepared for use as a visible light-activated photocatalyst, which exhibited significantly increased visible light absorption and improved photocatalytic activity, compared with Ag/TiO(2) and TiO(2)/graphene nanocomposites. The increased absorption in visible light region is originated from the strong interaction between TiO(2) nanoparticles and graphene, as well as the surface plasmon resonance effect of Ag nanoparticles that are mainly adsorbed on the surface of TiO(2) nanoparticles. The highly efficient photocatalytic activity is associated with the strong adsorption ability of graphene for aromatic dye molecules, fast photogenerated charge separation due to the formation of Schottky junction between TiO(2) and Ag nanoparticles and the high electron mobility of graphene sheets, as well as the broad absorption in the visible light region. This work suggests that the combination of the excellent electrical properties of graphene and the surface plasmon resonance effect of noble metallic nanoparticles provides a versatile strategy for the synthesis of novel and efficient visible light-activated photocatalysts.

An innovative method for oxidative degradation of chitosan with molecular oxygen catalyzed by metal phthalocyanine in neutral ionic liquid.

A novel aqueous solution-ionic liquid biphasic catalytic system was established for the oxidative degradation of chitosan under mild conditions. In this process, the environmentally acceptable and inexpensive molecular oxygen was first used as oxidant, the metal phthalocyanine was immobilized in ionic liquid as catalyst, and the aqueous solution as medium carried the reactants and the products. Under vigorous stirring and heating, the reactants fully contacted the catalysts in the emulsion and chitosan efficiently degraded into water-soluble materials. At the end of the reaction, the catalytic system could be easily separated by simple decantation and could also be reused in subsequent runs without apparent change in activity. These characters are in favor of the elimination of pollution and the reduction of the economic cost in the large-scale production of the water-soluble chitosan derivatives in chemical industry.