Study On Preparation And Properties Of Cu₂O And Cu₂O/CNTs Composite Materials

ZnO and TiO₂ are the most commonly used photocatalysts.However,it is a pity that both of them can only be excited by ultraviolet light and near-ultraviolet light because of their broad band gap,hence only less than 5%solar energy can be utilized.Therefore,searching a kind of semiconductor photocatalyst which can make full use of solar energy has attracted the attention of researchers.The majority of irradiation?about 43%?of sunlight lies in the visible range,so photocatalysts that can be excited by visible light and make good use of solar energy.As a typical narrow band gap semiconductor materials,Copper oxide?Cu₂O?can be excited by visible light and making good use of solar energy.Therefore,Cu₂O has a good application prospect in the field of solar cell and visible photocatalytic degradation.Compared with single-phase photocatalysts,the composite photocatalyst materials exhibit good catalytic activity because they reduce the recombination of photo-electron and holes.In this paper,Cu₂O nanocrystals and Cu₂O/CNTs composites were synthesized,and the effects of different conditions on the structure,morphology,and properties of the materials were studied.In addition,a Cu₂O modified iron red epoxy primer was also prepared and its performance in the degradation of ethylbenzene was studied.The contents of this paper are summarized as follows:1.The shape-controlled hollow sphere Cu₂O nanomaterials were prepared by one-step solvothermal method at 180°C,and used Cu?NO₃?₂·3H₂O as raw material,ethylene glycol as reductant and PVP as surfactant.In this study,the influence of different Cu?NO₃?₂·3H₂O/PVP mass ratio and reaction time on the crystal structures,morphologies,surface area and optical properties of Cu₂O was researched.The photocatalytic mechanism of Cu₂O nanocrystals are also investigated.The results show that when the mass ratio of Cu?NO₃?₂·3H₂O/PVP was 45,it can be clearly seen that the surface of the hollow spheres is covered with Cu₂O crystal thorn.As the mass radio of Cu?NO₃?₂·3H₂O/PVP decreases from45 to 15,the surface of the hollow spheres is covered with Cu₂O crystal nanocubes.Decreasing the radio of Cu?NO₃?₂·3H₂O/PVP from 15 to 9,the surface of the hollow spheres is made from an assembly of smaller spherical particles.The surface of the spheres covered with Cu₂O crystal thorn show the optimal photocatalytic activity,and at the 10 min of irradiation,the photodegradation efficiency of methyl orange solution can reach up to94.3%.2.Acid-treated CNTs were obtained by acidification of pristine CNTs with a volumetric ratio of 3:1 mixture of sulfuric acid?H₂SO₄?and nitric acid?HNO₃?,and Cu₂O/CNTs composites were synthesized by one-step solvothermal method using Acid-treated CNTs as the carrier.The influence of the concentration of CNTs on the crystal structures,morphologies,surface area and optical properties of Cu₂O/CNTs composite materials was researched.The photocatalytic mechanism of Cu₂O/CNTs composite materials are also investigated.The results show that acid treatment enhanced the dispersibility of CNTs in water,so Cu₂O/CNTs composites with uniform dispersion of CNTs were synthesized.Moreover,the introduction of CNTs enhances the specific surface area and visible light absorption intensity of Cu₂O,and reduces the recombination between photo-electron and holes under visible excitation.Therefore,the photocatalytic activity performance of Cu₂O/CNTs composites is better than Cu₂O nanomaterials.In addition,with the increase of CNTs content,the photodegradation efficiency of the Cu₂O/CNTs composites increased first and then decreased.When the CNTs content was 0.2 g,the photodegradation efficiency was best,and at the 60 min of irradiation,the photodegradation efficiency of methyl orange solution can reach up to 92.1%.3.A Cu₂O modified iron red epoxy primer was prepared.The influence of the concentration of Cu₂O on the degradation efficiency of ethylbenzene was researched.The results show that the photodegradation efficiency of the coating increased first and then decreased.When the Cu₂O content was 3%,the degradation efficiency of ethylbenzene was best under visible light,and at the 24 h irradiation,the photodegradation efficiency of ethylbenzene can reach up to 37.9%.