Study On The Photoreactions Reaction And The C-H Activation Reaction Catalyzed By Transition Metal And Its Derivatives

In recent years,with the increasing problem of environmental pollution,the concept of green chemistry has been increasingly recognized by people.The photocatalytic reaction,which is recognized as one of the cheap and efficient green technologies,has been used by scientific research workers to solve the water pollution problem caused by some organic pollutants in the water environment.The traditional photocatalyst can only use the ultraviolet region,and the new photocatalyst suitable for the visible region is continuously developed by scientists.Although there is still a lot of work to be done in crystal structure,catalytic mechanism,etc.,the use of solar energy to drive chemical reactions has received considerable attention and has been taken as an important way to pursue environmental protection and green synthesis.The surface plasmon resonance effect of metal Ag nanoparticles enables it to have a strong ability to absorb visible light.Therefore,the preparation of a new type of composite photocatalyst with elemental Ag can not only improve the utilization of solar energy by photocatalyst,but also can effectively shorten the reaction time of catalytic degradation.Due to the transition metal has an unfilled d orbits,the chemical properties they exhibited are clearly different from those of other main group elements and showed higher activity.Because of their small size and large specific surface area,nanoscale materials often exhibit new properties different from conventional materials in some chemical reaction systems.Therefore,the research on the preparation,properties,and application of nanoscale materials has been received attention of the researchers at home and abroad.From the perspective of sustainable development of resources,the search for cheap and high-utilization catalysts has become one of the goals of scientific researchers.We have tried to use cheap transition metals instead of precious metals to catalyze certain organic reactions.The contents of the paper as follows:(1)We prepared cube-like nano Ag@AgCl crystals successfully through a one-pot process,and no surfactant was used during the reaction.We evaluated the photocatalytic properties of the prepared cube-like nano Ag@AgCl crystals by photodegradation reaction of model pollutant methyl orange(MO).The prepared nanocomposites were characterized by X-ray diffraction,scanning electron microscopy,energy dispersive x-ray spectroscopy,transmission electron microscopy,x-ray photoelectron spectroscopy,and ultraviolet-visible spectroscopy.The results showed that the pure cubic Ag@AgCl crystal had good photocatalytic properties under visible light.(2)We also studied a preparation of a spherical nano Ag@AgBr composite photocatalyst.The Ag@AgBr composited photocatalyst prepared by this method exhibits excellent degradation activity for aqueous organic dye solutions under sunlight irradiation,and also demonstrates that the catalyst can efficiently and stably catalyze some photoreactions under visible light.The good photocatalytic activity was due to the synergistic bidirectional optical excitation between the nanoparticle Ag plasma and the narrow band gap of the AgBr semiconductor.The prepared nanocomposites were also characterized by X-ray diffraction,scanning electron microscopy,energy dispersive x-ray spectroscopy,transmission electron microscopy,X-ray photoelectron spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis),fluorescence spectrophotometer,respectively.(3)We successfully prepared nano-copper by hydrothermal method and verified it by scanning electron microscopy.However,the allylation reaction of benzyl alcohol catalyzed by cheap nano-copper catalysts had failed,and the reason for the failure remains to be analyzed.