Study On The Degradation Properties Of Black Phosphorene And Its Composites Prepared By Ball Milling

The application of photodegradation technology depends on materials with high carrier mobility and suitable bandgap structures.Black phosphorus is a glaring two-dimensional monelemental material with a graphene-like layered structure.The band gap is distributed between 0.3 eV and 2.0 eV,and the band gap is adjusted with the thickness of the layers,which enables it to absorb visible light to near-infrared light and it has an ultra-high carrier migration of 1000 cm²V^-1S^-1.In addition,black phosphorus also has the oustanding characteristics of large specific surface area and good biocompatibility.Therefore,black phosphoene as a photocatalyst in the field of photocatalytic degradation shows a broad application prospect.On the other hand,the unique curly structure of MWCNTs leads to the sp³ hybridization of some carbon atoms inside the MWCNTs.And it also has the sp² hybridized atoms in the layers which could form conjugated large?bonds after mixing with the sp³ hybridized atoms.The existence of this electronic structure enables the MWCNTs to have a carrier transport system.This has important implications for electron-hole pair separation and electron transport in photocatalysts.Because of their large specific surface area and tubular structure,MWCNTs are also considered to be a highly effective adsorbent.This dissertation is started at the preparation of black phosphorene,explored on the optimized condition through high energy ball-milling method.The photocatalytic degradation ability of pure black phosphoene was also determined.We further connected MWCNTs which with no photocatalytic activity on the surface of black phosphoene to prepared the 2D/1D black phosphoene-MWCNTs hybrids material,and explored its photocatalytic degradation ability.The dissertation mainly carried out the following two aspects of work:(1)A simple and efficient high energy ball-milling method was used to prepare a few layers of black phosphoene,and its photodegradation ability was also measured.In this dissertation,we would carried out these experiments with the bulk black phosphorus prepared by ourselves.These experiments include exploration of the optimal ball-milling conditions and photodegradation test of few layers of black phosphoene.The ball-milling condtions consist of the mass ratio of material to grinding ball,ball-milling time,ball-milling speed and pretreatment influence.Through a series of experiments,we conclude that the optimal conditions are the mass ratio of material to grinding ball is 1:10,the ball-milling speed is 350 rpm,the ball-milling time is 12hours and pretreated by NaCl.Through AFM characterization,we successfully prepared a few layers of black phospholene with thickness of about 4-10 nm.It can degrade 33.84%of RhB solution at a concentration of 0.005 mg/ml in 60 min under visible light,while the bulk has little effect on Rh B.The reason of the effect of black phosphoene is not good enough is its rapid oxidation under ambient conditions.Therefore,it is necessary to improve its stability by preparing composite materials.(2)On the basis of the previous work,a new 2D/1D hybrids material with MWCNTs covalently bonded on the surface of black phosphoene was prepared by high-energy ball-milling method.After the morphology characterizations and a series of spectral and energy spectrum characterization.We draw a conclusion:MWCNTs was hybridized on the surface of black phosphoene by forming stable P-C covalent bonds.We also analyzed and tested the photodegradation ability,stability,recyclability,ROS groups and band structure of the hybrids material.We found that after 60 min of visible light irradiation,the degradation rate of the hybrid material to the concentration of 0.01mg/ml Rh B was 88.42%,and the degradation rate of black phosphoene was only22.02%.After several cycles,the photocatalytic activity of the hybrids material was retained steadly.The optical absorption also remained after being placed in natural conditions for 5 days.We found that when the mass ratio of MWCNTs was 15%,the hybrids material had the highest photocatalytic activity.The quenching experiment also proved that the ROS of the hybrids material in photodegradation is·O₂^-.Finally,through theoretical calculation and energy band test,we also analyzed the photodegradation mechanism of hybrid materials.