Visible Light-Induced Photocatalysis:Self-Fenton Degradation of p-CIPhOH Over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst

Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.

The self-assembly of gold nanoparticles in large-pore ordered mesoporous carbons

Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyrene-block-polyethylene-oxide(PS-b-PEO)diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions(30℃)in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.

Research Progress on Photocatalytic/Photoelectrocatalytic Oxidation of Nitrogen Oxides

The emission of nitrogen oxides(NO_(x))increases year by year,causing serious problems to our livelihoods.The photocatalytic oxidation of NO_(x)has attracted more attention recently because of its effi cient removal of NO_(x),especially for low concentra-tions of NO_(x).In this review,the mechanism of the photocatalytic oxidation of NO_(x)is described.Then,the recent progress on the development of photocatalysts is reviewed according to the categories of inorganic semiconductors,bismuth-based compounds,nitrogen carbide polymer,and metal organic frameworks(MOFs).In addition,the photoelectrocatalytic oxida-tion of NO_(x),a method involving the application of an external voltage on the photocatalytic system to further increase the removal effi ciency of NO_(x),and its progress are summarized.Finally,we outline the remaining challenges and provide our perspectives on the future directions for the photocatalytic oxidation of NO_(x).

A highly selective magnetic sensor with functionalized Fe/Fe_3O_4 nanoparticles for detection of Pb^(2+)

A magnetic sensor for detection of Pb^2＋ has been developed based on Fe/Fe3O4 nanoparticles modified by3-（3,4-dihydroxyphenyl）propionic acid（DHCA）. The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb^2＋ thus inducing the transformation of Fe/Fe3O4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time（T2） of the surrounding water protons. Upon addition of the different concentrations of Pb^2＋ to an aq. solution of DHCA functionalized Fe/Fe3O4 nanoparticles（DHCA-Fe/Fe3O4 NPs）（[Fe] = 90 mmol/L）, the change of T2 values display a good linear relationship with the concentration of Pb^2＋ from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb^2＋, DHCA-Fe/Fe3O4 NPs exhibited a high selectivity over other metal ions.

Photoelectrocatalytic reduction of CO_2 to methanol over a photosystem Ⅱ-enhanced Cu foam/Si-nanowire system

A solar-light double illumination photoelectrocatalytic cell（SLDIPEC） was fabricated for autonomous CO2 reduction and O2 evolution with the aid of photosystem II（PS-II, an efficient light-driven water-oxidized enzyme from nature） and utilized in a photoanode solution. The proposed SLPEC system was composed of Cu foam as the photoanode and p-Si nanowires（Si-NW） as the photocathode. Under solar irradiation, it exhibited a super-photoelectrocatalytic performance for CO2 conversion to methanol, with a high evolution rate（41.94 mmol/hr）, owing to fast electron transfer from PS-II to Cu foam.Electrons were subsequently trapped by Si-NW through an external circuit via bias voltage（0.5 V）, and a suitable conduction band potential of Si（-0.6 e V） allowed CO2 to be easily reduced to CH3 OH at the photocathode. The constructed Z-scheme between Cu foam and Si-NW can allow the SLDIPEC system to reduce CO2（8.03 mmol/hr） in the absence of bias voltage. This approach makes full use of the energy band mismatch of the photoanode and photocathode to design a highly efficient device for solving environmental issues and producing clean energy.

Electrochemical construction of porous gold nanostructures on DVD substrate and its application as nonenzymatic hydrogen peroxide sensor

A simple acid-etching method was used to leach out silver from a bimetallic gold-silver based Digital Video Disc(DVD), which was further treated via a cyclic voltammetric scanning in 1 mmol/L HAu Cl4 solution to create a porous gold nanostructure. The as-fabricated electrode was characterized by field-emission scanning electron microscopy, energy-dispersed X-ray spectroscopy and X-ray diffraction. The high electro-catalytic activity of the resulting electrode toward the reduction of hydrogen peroxide(H2O2) presented excellent linear relationship in the range of 8.0×10?5 to 1.26×10?2 mol/L with the detection limit of 2.0×10-5 mol/L(S/N=3). The as-developed non-enzyme-sensor showed good reproducibility, stability, and selectivity.

Cytotoxicity of mitochondrial-targeting silica-coated manganese oxide nanoparticles

The mitochondrion is a promising target for diagnosis and therapy. Mitochondrial-targeting silica-coated manganese oxide nanoparticles(Mn O@Si O2-PPh3+ NPs) were successfully synthesized to explore the mitochondrial cytotoxicity of nanoparticles. The mitochondrial targeting property was confirmed by a laser scanning confocal microscopy experiment. Even after incubation for only 4 h, the cytotoxicity of Mn O@Si O2-PPh3+ NPs against cancer cells was obvious; the ATP content was significantly decreased to 40%; and the mitochondrial membrane potential was depleted. All of these results indicated the collapse of mitochondrial function and the start of a cell apoptosis pathway. Our findings suggest that mitochondrial-mediated apoptosis could be strengthened by targeting to the subcellular compartment.

Preparation and synergetic catalytic effects of amino-functionalized MCM-41 catalysts

Four amine functionalized mesoporous catalysts were synthesized by grafting primary, dualistic and two secondary amines onto the channel walls of mesoporous silica, MCM-41. We examined the effects of organoamine loading amount on the acid-base synergism of the catalysts in the self-condensation reaction of n-butanal, a Knoevenagel condensation and a Henry reaction. We observed the balance of the amine and residual silanol amounts is crucial to the catalytic performances of the functionalized mesoporous catalysts. An optimum organoamine loading amount exists, which is dependent on the organoamine type. There is little difference in the optimum organoamine loading amount between different reactions. The secondary organoamine functionalized MCM-41 exhibits the best catalytic performance in the experimental range.

Barley leaves mediated biosynthesis of Au nanomaterials as a potential contrast agent for computed tomography imaging

Over the past few years, environment-friendly green synthetic methods for metal nanoparticles(NPs) have received considerable attention. The use of plant extracts is considered as potential for the biosynthesis of metal NPs due to its easier obtainment, cheap accessibility to industrial scale-up and high biosecurity. Herein, with the aqueous leaf extract of barley leaves as the template, we reported a rapid, single step, cost-effective and eco-friendly synthetic route to prepare new gold nanoparticles(BL-Au NPs).Significantly, except for the key role as the reducing, barley leaves was further utilized as the capping agent that ensure the stability of the BL-Au NPs. The characterization results of TEM, FTIR and UV-vis indicated that the gold nanoparticles coated with barley leaves extract were successfully synthesized. In vitro and zebra fish toxicity and stability assays demonstrated its good biocompatibility and high colloidal stability. The CT images in vitro demonstrated that the constructed BL-Au NPs possessed superiority in X-ray attenuation ability compared to clinically commonly used iodinated small molecular contrast agent. And BL-Au NPs can be used as contrast agent for effective CT imaging of zebra fish model. These results suggest the potential utility of BL-Au NPs as a CT imaging contrast agent in clinical CT imaging based diagnosis.

Catalytic reduction of low-concentration CO_2 with water by Pt/Co@NC

The reduction of low-concentration carbon dioxide with water to organic fuels is still a huge challenge. In this study, we successfully designed the partially oxidized cobalt nanoparticles coated by the nitrogendoped carbon layer(Co@NC) of 2-8 nm via a facile method and then interspersed with different amount of Pt nanoparticles. The Co@NC decorated with 1 wt% Pt exhibits the best ability for COreduction to CHand a CHproduction rate of 14.4 μmol·g·his achieved. It is worth noting that the system is carried out under low-concentration CO(400 ppm) circumstance without any sacrificial agent, which could be meaningful to the design of catalysts for atmospheric COreduction.

One-pot enantioselective construction of 3,4-dihydro-2H-1,4-oxazines over Ru/Au relay catalysis and its mechanistic serendipity

The preparation of enantiomerically pure 1,4-oxazines remains a continuous challenge in synthetic chemistry because of their potential application in the total synthesis of morpholines.Herein,a one-pot asymmetric transfer hydrogenation/cyclization enantio-relay process catalyzed by Ru and Au bimetallic catalysts was developed.This enantio-relay process firstly allows the asymmetric transfer hydrogenation of alkynones to form chiral alkynols in the presence of(S,S)-mesityleneRuClTsDPEN(TsDPEN=N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine)and then the chiral alkynols could be converted into 3,4-dihydro-2H-1,4-oxazines in moderate to good yields with excellent enantioselectivity retention accompanied by AuCl(PPh_(3))/AgNTf_(2) and HCOOH.A series of sulfonamide-tethered alkynones were well tolerated in this process.Mechanistic studies indicated that the alkynols formed in the first step were initially transformed into a methylenemorpholine intermediate when AuCl(PPh_(3))/AgNTf_(2) and HCOOH were added,which can be further isomerized into chiral 3,4-dihydro-2H-1,4-oxazines with the addition of a second HCOOH.This protocol offers not only a practical method to access 3,4-dihydro-2H-1,4-oxazines from alkynones in an enantioselective version,but also enriches the arsenal of gold chemistry from a mechanistic point of view.

Immobilization of chiral Rh catalyst on glass and application to asymmetric transfer hydrogenation of aryl ketones in aqueous media

A chiral catalyst, Cp＊RhTsDPEN （Cp＊ = pentamethyl cyclopentadiene, TsDPEN = substitutive phenylsulfonyl-l,2-diphenylethylenediamine）, was synthesized and immobilized at the surface of glass. The immobilized catalyst exhibited good catalytic efficiency for asymmetric transfer hydrogenation of aromatic ketones in water with HCOONa as hydrogen source.

Engineering Pt heterogeneous catalysts for accelerated liquid–solid redox conversion in Li-S batteries

The shuttle effect caused by soluble lithium polysulfides (LiPSs) deteriorates multiphase transformation reaction kinetics of sulfur species,and gives rise to an unserviceable lithium-sulfur (Li-S) battery.Catalysis,as a process optimization approach,offers an option to eliminate the intrinsic issues.However,exploring and understanding the role of catalysts on electrode reaction remains critical bottlenecks,particularly as they are prone to continuous evolution under complex dynamic environment.Herein,platinum nanoparticles loaded on MXene nanosheets,as sulfur host,and the action of catalysts on the reaction process are investigated via ex-situ monitors upon solid–liquid–solid chemical transformation of sulfur species.These traces confirm that the high performance originates from electron transfer between catalysts and LiPSs,which lowers the nucleation barrier from liquid LiPSs to solid Li_(2)S/Li_(2)S_(2).Further,the accelerated liquid–solid conversion can alleviate the accumulation of LiPSs,and boost the reaction kinetics in Li-S batteries.The findings corroborate the electronic modulation between catalysts and LiPSs,which is a generalizable strategy to optimize energy conversion efficiency of Li-S batteries.

A polyoxometalate-functionalized two-dimensional titanium carbide composite MXene for effective cancer theranostics

As a new family of two-dimensional （2D） nanomaterials, MXenes have recently attracted much attention because of high performance in versatile applications including energy storage and electrochemistry, but their specific application to biomedicine has been rarely reported, especially for theranostic nanomedicine, i.e., concurrent diagnostic imaging and therapy. This study shows for the first time surface engineering and functionalization of 2D Ti3C2 MXene nanosheets by the integration of GdWl0-based polyoxometalates （POMs）. These multifunctional GdWlo@Ti3C2 composite nanosheets provide hypertherrnal treatment with magnetic resonance （MR） and/or computed tomography （CT） imaging guidance toward tumor cells or xenografts. A tumor was effectively eradicated without further reoccurrence during the observation period. GdW10 nanoclusters that were integrated onto the surface of Ti3C2 nanosheets were demonstrated to serve as a contrast agent for contrast-enhanced CT and MR imaging based on their unique composition, thus showing the potential for diagnostic-imaging guidance and monitoring for tumor hyperthermia nanotherapy. The high in vivo biocompatibility of GdW10@TiaC2 composite nanosheets was demonstrated to guarantee their subsequent translation into a medical treatment. This study provides a novel strategy for broadening the biomedical applications of MXenes by surface engineering and multifunctionalization, which is expected to promote further exploration of biomedical applications of MXenes in nanotheranostics.

Two-dimensional Ni（OH）2 nanoplates for flexible on-chip m icrosu pe rcapac itors

有集成电路的在薄片上几何学的在薄片上 microsupercapacitors (MSC ) 兼容机也能在 microelectronic 设备或作为精力存储或精力受体附件单位被用作分开的电源供应。在这个工作，我们报导灵活二维的 Ni 的制造(哦)基于 nanoplates 的 MSC，它在扫描完成了 8.80 F/cm 3 的一个特定的电容 100 mV/s 评估的 2 ，仅仅在 10,000 控告 / 解除以后失去 0.20% 它的原来的价值骑车。而且， MSC 到达了 0.59 mWh/cm 3 的精力密度和电源密度直到比得上传统的基于碳的设备的 1.80 W/cm 3, 。当使遭到了到以各种各样的条件弯曲时，灵活 MSC 展出了好电气化学的稳定性，说明象为便携精力存储的电极的有希望的申请。

Reversible fluorescent probes for chemical and biological redox process

Oxidation and reduction are important chemical and biological processes. The redox state is related with physical functions and health. Thus, it is meaningful to develop tools for study the redox process.Fluorescence is a powerful method to connecting the microcosm and macrocosm. In this review, we discuss the recent progress of reversible fluorescent probes for chemical and biological redox process according to different active centers.

Acid-induced tunable white light emission based on triphenylamine derivatives

A series of triphe nylamine(TPA)derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect.On account of the existence of pyridine units,these TPA derivatives exhibited acid-induced tunable multicolor fluorescence emission including white light emission.In addition,acid-induced fluorescence regulation of these compounds has been also realized in the solid state,which enable them to be successfully constructed the stimuli-responsive fluorescent films and fluorescent inks for inkjet printing.

Fluorescence-resonance energy transfer(FRET)within the fluorescent metallacycles

During past few years,the construction of fluorescent metallacycles featuring the fluorescenceresonance energy transfer behavior has attracted extensive attention due to their diverse applications such as real-time monitoring the dynamics of coordination-driven self-assembly,photoswitching fluorescence-resonance energy transfer,and light-controlled generation of singlet oxygen for cancer therapy.This review focuses on the recent advances on the design principles,preparation methods,optical properties,and the wide applications of fluorescent metallacycles with the FRET property.