Preparation of Oxygen-Doping Nongraphitic Carbon Nitride via Efficiency Exfoliation for the Application of Photocatalytic Degradation.

E-OLCN photocatalyst was synthesized by oxygen doping of low molecular weight carbon nitride (LCN) with ethanol solvent stripping. The enhanced light absorption, fast electron transport rate, and photogenerated carrier separation efficiency of E-OLCN leads to the excellent photocatalytic degradation performance compared with the original materials. The synergistic effect of oxygen doping and ethanol solvent stripping plays a significant role for the modulation of electronic and structural properties of the prepared catalysts. Methyl orange (MO) and rhodamine B (RhB) are chosen as typical pollutants for the application of photocatalytic degradation. The E-OLCN sample exhibits outstanding photocatalytic degradation performance, where the rate constant k (1 × 10-2 min-1) of E-OLCN (1.68) is 2.9 times than that of O-LCN (0.58) and 8.8 times than that of pristine LCN (0.19) for MO. Moreover, modulated E-OLCN shows good stability after cycling experiments and the activity still achieved 90%. The detailed mechanism for MO degradation was proposed with the technical support of liquid chromatography-mass spectrometry (LC-MS) and electron spin resonance (EPR). The superoxide radical (·O2-) is the main active species and the MO molecule could be decomposition completely.

Exploring the In Situ Formation Mechanism of Polymeric Aluminum Chloride-Silica Gel Composites under Mechanical Grinding Conditions: As a High-Performance Nanocatalyst for the Synthesis of Xanthene and Pyrimidinone Compounds.

The use of mechanical ball milling to facilitate the synthesis of organic compounds has attracted intense interest from organic chemists. Herein, we report a new process for the preparation of xanthene and pyrimidinone compounds by a one-pot method using polymeric aluminum chloride (PAC), silica gel, and reaction raw materials under mechanical grinding conditions. During the grinding process, polymeric aluminum chloride and silica gel were reconstituted in situ to obtain a new composite catalyst (PAC-silica gel). This catalyst has good stability (six cycles) and wide applicability (22 substrates). The Al-O-Si active center formed by in situ grinding recombination was revealed to be the key to the effective catalytic performance of the PAC-silica gel composites by the comprehensive analysis of the catalytic materials before and after use. In addition, the mechanism of action of the catalyst was verified using density functional theory, and the synthetic pathway of the xanthene compound was reasonably speculated with the experimental data. Mechanical ball milling serves two purposes in this process: not only to induce the self-assembly of silica and PAC into new composites but also to act as a driving force for the catalytic reaction to take place. From a practical point of view, this "one-pot" catalytic method eliminates the need for a complex preparation process for catalytic materials. This is a successful example of the application of mechanochemistry in materials and organic synthesis, offering unlimited possibilities for the application of inorganic polymer materials in green synthesis and catalysis promoted by mechanochemistry.

Transition Metal Doping Induces Ti3+ to Promote the Performance of SrTiO3 @TiO2 Visible Light Photocatalytic Reduction of CO2 to Prepare C1 Product.

Transition metal Fe, Co, Ni and Cu doped strontium titanate-rich SrTiO3 @TiO2 (STO@T) materials were prepared by hydrothermal method. The prepared doped materials exhibit better photocatalytic CO2 reduction to CH4 ability under visible light conditions. Among them, Fe-doped and undoped SrTiO3 @TiO2 under visible light conditions CO2 reduction products only CO, while M-STO@T (M=Co, Ni, Cu) samples converted CO2 to CH4 . The average methane yield of Ni-doped STO@T samples are as high as 73.85 µmol g-1 h-1 . The production of methane is mainly due to the increase in the response of the doped samples to visible light. And the increase in the separation rate of photogenerated electrons and holes and the efficiency of electron transport caused by the generation of impurity levels. The impurity level caused by Ti3+ plays an important role in the production of methane by CO2 visible light reduction. Ni doping effectively improves the photocatalytic performance of STO@T and CO2 reduction mechanism were explained.

Copper and palladium bimetallic sub-nanoparticles were stabilized on modified polyaniline materials as an efficient catalyst to promote C-C coupling reactions in aqueous solution.

Modified polyaniline self-stabilizing Cu/Pd bimetallic sub-nanocluster composite materials (Cu/Pd@Mod-PANI-3OH) are obtained through the three steps of oxidative polymerization, structural modification, and metal self-trapping. Palladium and copper are confined and coordinated in the composite material by participating in the reaction and are highly uniformly dispersed in the carrier in the form of sub-nano clusters. The Cu/Pd@Mod-PANI-3OH micro-nano reactor catalyst formed by the self-assembly of copper, palladium and polyaniline has excellent electronic effects, including a tunable microenvironment, metal-carrier and metal-metal synergy, and the stabilizing effect of metal by polyaniline materials. It can efficiently catalyse C-C coupling (Sonogashira and Suzuki) reactions in aqueous solution with high catalytic activity and a wide range of applications (40 substrates). The characterization test results show that the Cu/Pd@Mod-PANI-3OH composite material obtained by self-trapping metal is a kind of prefabricated catalyst. During the reaction process, the high-valent metals in the pre-catalyst are in situ converted into active zero-valent metals. The catalyst's pre-fabrication strategy well protects the catalytic active centre, largely prevents agglomeration of the metal particles (can be recycled 8 times) and exhibits excellent interfacial domain-limited catalysis. The research strategy of modulation of catalytic active sites to improve the properties of materials at the molecular and atomic level reported in this article will open a new door in the research of polyaniline materials.

The new life of traditional water treatment flocculant polyaluminum chloride (PAC): a green and efficient micro-nano reactor catalyst in alcohol solvents.

Polyaluminum chloride (PAC) is an inorganic polymer material that has the advantages of a simple preparation process and special electronic structure. It is considered to be the most efficient and widely used flocculation material for water treatment. In this work, PAC has been used as a Lewis acid catalyst in interdisciplinary fields because of its polynuclear Al-O cation structure. Further, its catalytic mechanism in green organic synthesis has been studied in detail by using the multicomponent Biginelli reaction as the probe. The effect of solvent on the self-assembly and aggregation process of PAC materials was investigated using optical microscopy, UV-Vis spectrophotometry, particle size analysis, XPS, IR, SEM and HR-TEM. The results show that the PAC materials have different morphological characteristics in different solvents. The Al-O-Al cations were transformed in the ethanol solvent to form new multi-nuclear cation aggregates Alb, which could be used as inorganic micro-nano reactors with unique synergistic catalysis in catalytic reactions. This is the first time the role of PAC in the Biginelli reaction has been analyzed with a liquid in situ infrared instrument, which provided favorable evidence for the speculated reaction mechanism. The PAC-ethanol system is, therefore, considered to be a green, efficient (best yield >99%), economic and recyclable catalyst for catalyzing organic synthesis reactions. The development and utilization of PAC materials in organic synthesis will bring new vitality to this cheap material, which is widely used in industries.

A water resistance magnetic graphene-anchored zeolitic imidazolate framework for efficient adsorption and removal of residual tetracyclines in wastewater.

Water-resistant magnetic graphene-anchored zeolite imidazolate (Fe3O4/ZIF-8-G) composite materials with the largest surface area are formed by directly growing a hydrophobic ZIF-8 skeleton onto a graphene support through self-assembly in methanol. Fe3O4/ZIF-8-G hybrid composite has water resistance and super strong adsorption capacity, and is used as an effective adsorbent for adsorption and removal of residual tetracycline in wastewater. The morphologies and structure, as well as water resistance of Fe3O4/ZIF-8-G, were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry analysis (TGA), N2 adsorption and pHPZC. The adsorption for tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) followed pseudo-second-order kinetics and fitted the Freundlich adsorption model with the simultaneous adsorption capacity for TC (382.58 mg g-1), OTC (565.94 mg g-1) and CTC (608.06 mg g-1) at pH 5-6 for 10 h. These were much higher than previously reported results for the removal of tetracycline from aqueous solutions. The used Fe3O4/ZIF-8-G could be effectively reused and recycled at least five times without significant loss of adsorption capacity. The hydrophobic and π-π interaction between the aromatic rings of TCs and the aromatic imidazole rings of the ZIF-8-G framework were the main adsorption mechanism on the surface of Fe3O4/ZIF-8-G. Constructing a hydrophobic surface of ZIF-8/G framework resulted in a reduction of the hydrophilic sites of the surface. This can improve stability and selective adsorption of ZIF-8-G framework. In addition, the results show no significant difference in the adsorption kinetics and adsorption capacity of Fe3O4/ZIF-8-G for TC, OTC and CTC in pure water and wastewater.

High acidity cellulose sulfuric acid from sulfur trioxide: a highly efficient catalyst for the one step synthesis of xanthene and dihydroquinazolinone derivatives.

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g-1) was successfully prepared by SO3 gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

Influence of coal ash on potassium retention and ash melting characteristics during gasification of corn stalk coke.

This study experimentally investigated the potassium fixation ability and ash fusion characteristics during the gasification of corn stalk coke blended with coal ash in CO2 atmosphere. The ash samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). FactSage was also employed to calculate the components and quantities of solid and liquid phase. The results show that the ratio of potassium retained in the biomass ash decreases with the increase in the gasification temperature. In addition, the retention ratio increases with more coal ash added. The improvement of potassium retention ratio is due to the reaction of potassium with alumina/silica to form the solid/slag phase of the potassium aluminosilicates. On the other hand, the ash fusion temperatures of the blended ash are increased by adding the coal ash, compared with the biomass ash. The study confirms that coal ash is a potential additive for not only fixing potassium, but also increasing the ash fusion temperatures of easy-to-slagging biomass.

[Determination of metformin hydrochloride, melamine and dicyandiamide in metformin hydrochloride preparations by tandem dual solid phase extraction cartridges-high performance liquid chromatography-electrospray ionization multi-stage mass spectrometry].

A method for the confirmation and quantification of metformin hydrochloride and its relative substances melamine and dicyandiamide using tandem dual solid phase extraction (SPE) cartridges and high performance liquid chromatography-electrospray ionization multi-stage mass spectrometry (HPLC-ESI-MSn) was developed. The samples were extracted with anhydrous ethanol containing 0.1% (v/v) acetic acid under ultrasound-assisted conditions. The extracts were concentrated and purified using Cleanert PCX and C18 tandem dual solid phase extraction cartridges, and eluted with 5% (v/v) ammonia methanol solution. The separation was performed on a Kromasil-C18 column (100 mm×4.6 mm, 3.5 µm) with gradient elution. The detection was performed in selected ion monitoring (SIM) mode using electrospray ionization multi-stage mass spectrometry. The external standard method was used for quantification. The extraction solvents, types of SPE cartridges and eluents were optimized by comparing the recoveries under different conditions. The results showed that the detector response of each target compound was linear in corresponding mass concentration ranges with the correlation coefficients (r2) ≥ 0.9992. The limits of detection (LODs) and the limits of quantification (LOQs) of the three analytes were 1.48-13.61 µg/kg and 5.96-45.67 µg/kg, respectively. The recoveries of the three analytes were 65.02%-118.33% spiked at low, medium and high levels. The relative standard deviations (RSDs) were no more than 13.41%. The method is reliable, easy, and has a better purification effect. The method can be applied to the routine analysis of metformin hydrochloride and its relative substances melamine and dicyandiamide in different preparations of metformin hydrochloride.

Mo2 C as Non-Noble Metal Co-Catalyst in Mo2 C/CdS Composite for Enhanced Photocatalytic H2 Evolution under Visible Light Irradiation.

Co-catalysts are a major factor to enhance photocatalytic H2 activity; they are mainly composed of expensive noble metals. Here, we reported a new non-noble-metal co-catalyst Mo2 C that efficiently improves the photocatalytic H2 evolution of CdS under visible light irradiation. Mo2 C is prepared by temperature-programmed reaction with molybdenum oxide as precursor, and the Mo2 C/CdS composite is prepared by deposition of CdS on Mo2 C. The optimum composite 2.0 % Mo2 C/CdS shows a high H2 evolution rate of 161 µmol h(-1) , which is ten times higher than that of CdS alone and 2.3 times higher than the optimum for 1.0 % Pt/CdS. Moreover, the Mo2 C/CdS is stable for 50 h. This study presents a new low-cost non-noble-metal co-catalyst as a photocatalyst to achieve highly efficient H2 evolution.

Phase transition of silica in the TMB-P123-H2O-TEOS quadru-component system: a feasible route to different mesostructured materials.

Various siliceous structures were obtained using a nonionic block copolymer (Pluronic P123) surfactant and trimethylbenzene (TMB) as a hydrophobic additive by hydrolysis and condensation of tetraethoxysilane (TEOS) in a sol-gel process. The resultant materials were characterized by small-angle X-ray diffraction (SAXRD), nitrogen adsorption analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results revealed the structure transformation from hexagonal structure (HEX) to multilamellar vesicles (MLVs) and then to mesocellular foams (MCFs) in the TMB-P123-H2O-TEOS quadru-component system. The morphology of the mesoporous silica was mainly controlled by the mass ratio of TMB/P123 resulted from the increasing volume of the hydrophobic chain of micelle of P123 that caused by more amount of TMB dissolved in the PPO segment of polymer. The fact that the occurrence of rod-like particles with curved ends and the coexistence of the MLVs and the HEX structure indicates that the MLVs are developed from the ends of HEX structures, rather than formed by a direct cooperative self-assembly mechanism. Further increasing of packing parameter of surfactant resulted from TMB addition transforms lamellar micelles to reversed micelles, leading to the formation of MCFs.