Polycyclic HPAHs Conjugated Molecules Promote High Efficiency Transfer Of Hot Electrons In Metal Nanoparticles Of Copper And Their Photocatalytic Reduction Of CO₂

In recent years,plasma photocatalysts with local surface plasmon resonance（LSPR）have attracted extensive attention in the field of photocatalytic technology.Metal nanoparticles（Au,Pt,Ag,Cu,etc.）can effectively convert low-energy solar photons into chemical energy through metal local surface plasmon resonance（LSPR）.However,the metal nanoparticles themselves have the problem of high carrier recombination rate,which leads to too low hot electron transport efficiency.Therefore,in this paper under a simple photocatalytic system,we first explored the different local surface plasmon resonance（LSPR）of metal and metal copper of different shape of the local surface plasmon resonance（LSPR）,the effect of further through organic precision guidance synthesis for a class of polycyclic complex aromatics conjugated molecular load copper nanoparticles（Cu NPs）.The plasma composite catalyst can greatly improve the thermal electron transfer efficiency of copper.The separation and transfer process of thermoelectric charge excited by LSPR effect of composite materials were further studied by component analysis and photoelectric characterization,so as to reveal the photocatalytic reaction mechanism of LSPR effect.Specific research work is as follows:（1）In situ reduction experiments were carried out on common metals by in-situ reduction method and their photocatalytic reduction performance was tested.Cu NPS has the best photocatalytic performance,and the production rates of CO and CH₄ are404.46 and 42.59μmol g^-1 h^-1,respectively.Through qualitative analysis of XRD,it is confirmed that the substance generated in this system is elemental metal nanoparticles.Then a series of elemental copper with different morphologies were synthesized by different reduction methods and the photocatalytic reduction performance of elemental copper with different morphologies in this system was studied.Finally,the possible mechanism of photocatalytic reduction of CO₂ by Cu NPs was speculated.（2）A class of conjugated polycyclic heteroaromatic hydrocarbons（PAHs）were designed and synthesized.Cu NPs were supported by a simple in situ photoreduction strategy.Among them,the best photocatalytic performance of Cu NPs supported by1,3,5-tri（10H-phenothiazin-10-yl）benzene（TPB）was obtained.The CO generation rate of TPB-Cu composite was significantly increased to 1308.8μmol g^-1 h^-1,which was 3.2 times higher than that of the original Cu NPs.However,the activities of the other two gas products（H₂ and CH₄）did not change significantly.The photocatalytic activity of Cu NPs with different number of phenothiazine units was explained by photoelectric characterization.The effects of heteroatom（S）and molecular structure on the photocatalytic performance of 1,3,5-tri（10H-phenothiazin-10-yl）benzene were further studied.The distribution of Cu NPs in the composite TPB-Cu was analyzed by TEM and EDS,etc.It was shown that the agglomeration of Cu NPs was restricted and the migration of hot electrons of Cu NPs was promoted,thus the photocatalytic performance of the composite TPB-Cu was enhanced.