Study On The Photocatalytic Performance Of Composites Based On Metal-porphyrin Frameworks/two-dimensional Carbon Materials

Photocatalytic degradation of pollutants,which can utilize solar energy effectively and degrade organic pollutants efficiently,is an important measure to alleviate the problems of environment and energy.The key to photocatalysis is to find efficient,stable and low-cost photocatalysts.In this paper,a metal-porphyrin framework PCN-222(Zn)was selected as the photocatalyst,and it was compounded with two kinds of two-dimensional carbon materials,graphene and graphdiyne,respectively,to prepare the composite photocatalysts,which achieved efficient degradation of the organic dye rhodamine B(Rh B)under visible light irradiation.The influence of carbon materials type and amount on the performance of the photocatalysts was explored.The main research contents and conclusions are as follows:1.Pyridine-graphene(py GR)was prepared from graphene oxide(GO),and the composites PCN-222(Zn)with GO and py GR were prepared by in-situ hydrothermal method.We characterized the obtained samples and compared the photocatalytic performance of the two composites in the degradation of Rh B.In addition,we conducted a kinetic simulation of the degradation process.The performance of PCN-222(Zn)/py GR is more excellent when with the equal amount of GO and py GR.The effect of py GR amount on performance of composite was explored,and the reactive species and possible photocatalytic mechanism were determined through the trapped experiments.PCN-222(Zn)/py GR composite possesses the optical performance when the mass fraction of py GR is 1.2 %,its reaction kinetic constant is 1.93 times that of PCN-222(Zn),and it exhibited good recyclability and stability.2.Graphdiyne(GD)film was prepared by liquid-liquid interface method,and modified to prepare pyridine-graphene(py GD).Composites of PCN-222(Zn)with GD and py GD were prepared and characterized.And we compared the photocatalytic performance of the two composites in the degradation of Rh B.The performance of PCN-222(Zn)/GD is better.We explored the effect of GD amount on performance of composite,and determined the reactive species and possible photocatalytic mechanism through the trapped experiments.PCN-222(Zn)/GD possesses the optimal performance when the mass fraction of GD is 0.6 %,its reaction kinetic constant is 1.99 times that of PCN-222(Zn),and it exhibited good recyclability and stability.The above experimental results showed that the introduction of carbon materials into the structure of the metal-porphyrin framework PCN-222(Zn)can effectively improve its photocatalytic performance by inhibiting the recombination of photogenerated electron-hole.The key to improve the photocatalytic performance of composites is the ordered interaction between the two components.