Limei Zhou

Synthesis of Copper Graphene Materials Functionalized by Amino Acids and Their Catalytic Applications

Graphene oxide and its derivative have attracted extensive interests in many fields, including catalytic chemistry, organic synthesis, and electrochemistry, recently. We explored whether the use of graphene after chemical modification with amino acids to immobilize copper nanoparticles could achieve a more excellent catalytic activity for N-arylation reactions. A facile and novel method to prepare copper supported on amino-acid-grafted graphene hybrid materials (A-G-Cu) was first reported. The as-prepared hybrid materials were characterized by a variety of techniques, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and inductively coupled plasma-atomic emission spectrometry. The results showed that the morphology, distribution, and loading of copper nanoparticles could be well-adjusted by controlling the type of amino acids grafted on graphene. Moreover, most A-G-Cu hybrid materials could catalyze N-arylation of imidazole with iodobenzene with yields more than 90%, while the copper supported on graphene (G-Cu) displayed a yield of just 65.8%. The high activity of A-G-Cu can be ascribed to the good synergistic effects of copper nanoparticles (Cu NPs) and amino-acid-grafted graphene.

Highly efficient pollutant removal of graphitic carbon nitride by the synergistic effect of adsorption and photocatalytic degradation

Environmental remediation based on semiconducting materials offers a green solution for pollution control in water. Herein, we report a novel graphitic carbon nitride (g-C3N4) by one-step polycondensation of urea. The novel g-C3N4 material with a surface area of 114 m2 g−1 allowed the repetitive adsorption of the rhodamine B (RhB) dye and facilitated its complete photocatalytic degradation upon light irradiation in 20 min. This study provides new insights into the fabrication of g-C3N4-based materials and facilitates their potential application in the synergistic removal of harmful organic pollutants in the field of water purification.

Cu nanoparticles immobilized on montmorillonite by biquaternary ammonium salts: a highly active and stable heterogeneous catalyst for cascade sequence to indole-2-carboxylic esters

Copper nanoparticles immobilized on montmorillonite (MMT) by biquaternary ammonium salts (N1,N6-dibenzyl-N1,N1,N6,N6-tetramethylheptane-1,6-diaminium bromide, Q) were prepared by cation-exchange and impregnation–reduction and designated Cu-Q-MMT. The material was extensively characterized by various characterization techniques such as FTIR, XRD, XPS, SEM, TEM, and N2 adsorption–desorption. The Cu-Q-MMT could be used as a highly active heterogeneous catalyst for cascade sequence to indole-2-carboxylic esters from ortho-bromobenzaldehydes with ethyl acetamidoacetate. Even for inactive chlorobenzaldehydes, a good yield could be obtained. In addition, the catalyst can be reused six times without any significant loss of activity. The high activity and stability of the Cu-Q-MMT catalyst is mainly attributed to the excellent synergistic effects of biquaternary ammonium salts, Cu nanoparticles and the nanospace structure of MMT.

Synthesis and characterization of 1,3-diamino-graphene as a heterogeneous ligand for a CuI-catalyzed C–N coupling reaction

1,3-Diamino-graphene (NH2-G-NH2) materials were synthesized using a simple chemical method. The as-prepared materials were characterized using FT-IR, TG, XRD, XPS, and SEM measurements. The results revealed that a 1,3-diamino group was successfully grafted on graphene and could immobilize CuI by coordination interactions. The NH2-G-NH2 materials can be used as heterogeneous ligands for CuI-catalyzed C–N coupling reactions, and the desired products were obtained with good yields. The reaction system is much smoother at lower temperature compared with others previously reported. Additionally, the new method can easily realize the purification of products and recycling of catalysts.

Recyclable hydrophobic copper (II) phthalocyanine catalyzed N-arylation of imidazoles in dimethylsulfoxide

Abstract Copper (II) phthalocyanine (CuPc) was used as a catalyst for the N-arylation of imidazoles with aryl iodides or bromides. The catalyst showed high activity and could be reused 3 times without any significant loss in activity. The catalyst was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy.

Preparation and inhibition of 2-methyl cetyl pyridine bromide for X70 steel in 5M HCl

Abstract 2-Methyl cetyl pyridine bromide (namely MCPB) was synthesised and characterised by 1H NMR,13C NMR and Fourier transform infrared spectroscopy. The inhibitive effect of MCPB on X70 steel in 5M HCl was investigated by weight loss, Tafel polarisation and electrochemical impedance spectroscopy. Results showed that the adsorption of MCPB on X70 steel surface obeyed the Langmuir adsorption isotherm. Inhibition efficiency increased with MCPB concentration and was up to 98·18% at 10 μM of MCPB. Cathodic and anodic polarisation curves of X70 steel indicated that MCPB acted as a mixed type inhibitor. The values of , and manifested a spontaneous and exothermic adsorption of MCPB on X70 steel surface accompanied by entropy increase.

Comparison of Fe/surfactant improved montmorillonite: adsorbing and in situ decomposing methylene blue and recycling use

AbstractMontmorillonite (MMt) was intercalated by polymeric Fe, or by N-ethyl dodecyl nicotinate bromide (EDNB), or by both. The improved MMt designated as Fe/MMt, EDNB/MMt, and EDNB/MMt/Fe, respectively. A comparison was performed on the improved MMt in the uptake and in the degradation of methylene blue (MB) as well as in the recycling use. The results showed that EDNB/MMt adsorbed more MB than the other two; however, Fe/MMt and EDNB/MMt/Fe acted faster than the former. The adsorption of MB on the three adsorbents followed Langmuir isotherm and pseudo-second-order kinetics. In addition, MB adsorbing on EDNB/MMt was also well described by intraparticle diffusion model. MB removal by EDNB/MMt experienced an endothermic and entropy driving process, but an exothermic and entropy declining process by the other two. pH of the solution affected MB removal. When pH of the solution is high than 10, MB uptake diminished on Fe/MMt and EDNB/MMt/Fe; however, it slightly increased on EDNB/MMt. MB could be decomposed ...