Study On The Preparation And Properties Of Porphyrins Photoelectric Composites

In recent decades,semiconductor photocatalysis has attracted much more attention owing to particular features of green and high efficiency.It is considered as one of the effective methods to solve the environmental and energy problems.At present,many photocatalytic materials have been developed,but they have problems such as a large probability of carrier recombination,which restricts their wide application.In order to improve the photocatalytic properties of semiconductors,they were modified.Porphyrin,as a n type organic semiconductor,has been widely applied in the field of optoelectronic materials and solar cells,because of its suitable band gap,better photoelectric performance,faster electron injection efficiency and slower charge recombination kinetics.However,the single porphyrin also has the problem of low quantum efficiency.Therefore,porphyrin is used as a sensitizer to combine with nanomaterials to improve the overall catalytic performance.At present,the performance analysis method of photoelectric materials is single and limited.Only macroscopic comparisons were made on materials,and there was no deeper microscopic explanation.Therefore,in this paper,we use photoelectrochemical platform to build new analytical methods for materials.We comprehensively evaluate the excellence of our materials through multi angle performance analysis.The following work is divided into three parts.1.Study on preparation and photocatalytic properties of type II Bi2WO6/Zn-TCPP p-n heterojunction nanocompositesBi2WO6 is a common visible photocatalyst.It has good spectral response and catalytic performance.However,Bi2WO6 is difficult to be applied in the field of photocatalysis on a large scale,mainly due to its relatively high probability of photo-charge recombination.Therefore,we choose Zn-TCPP to combine with it,and utilize the heterojunction structure of organic and inorganic hybrid to accelerate the electron transfer rate and improve its catalytic performance.We optimized proportion of Bi2WO6/Zn-TCPP composite to prepare.At the same time,the photoelectric property test shows that the composite photocurrent is much larger than that of the pure material.It is also consistent with interfacial electron transfer rate obtained by scanning electrochemical microscope(SECM)platform.So combining the above two methods of analysis,we also explain the success of material modification.Finally,we optimized its wavelength and intensity,when 441 nm of the wavelength and 90% of the intensity of light,the response is best.2.Study on preparation and photocatalytic properties of THPP@Pt core-shell nanocompositesThe Core-shell nanomaterials have received extensive attention in recent years due to their large surface area and excellent light harvesting properties.In this chapter,the platinum nanoparticles and porphyrin were used to prepare THPP@Pt nano core-shell composite materials,to improve its performance by surface modified materials.The successful preparation of THPP@Pt was clearly seen by SEM and TEM.Then the proportion of composite was optimized and choosed the best proportion of 50:1.Through macroscopic photoelectric performance test,it is found that the interfacial resistance of composites decreases significantly,and its photocurrent increases.Finally,the above test results are verified by SECM,and the electron transfer path is explained reasonably.3.Study on preparation and photocatalytic properties of ZnO/Zn-TCPP NWs nanocompositesZnO is an ultraviolet photocatalyst.Due to its narrow spectral response,its performance and application are greatly limited.The unique one-dimensional structure of nanowires allows electronic transmission faster.Moreover,the light scattering and reflection can occur in the array structure,so that the optical absorption ability is enhanced.Therefore,the morphology of ZnO has been modified and sensitized it with porphyrin.In this chapter,ZnO/TCPP NWs and ZnO/Zn-TCPP NWs were prepared.After that,conventional characterizations were completed to prove that the materials were successfully prepared.Finally,two aspects of macroscopic photoelectric performance test and microscopic electron transfer analysis were selected to test their properties.The test results showed that the electron transfer rate of the composite material was significantly improved which further indicates that the modification of materials is successful.