The Preparation,Characterization And Dye Catalytic Degradation Over Cu₂O-Cu/Ni And Ag-Cu/Cu₂O/Ni

The organic dye wastewater has of color depth,toxicity,complex composition and it is hard to be degraded,which is a huge threat to the environment and human health.In this paper,hydrothermal and thermal oxidation method were employed to prepare Cu2O-Cu/Ni and Ag-Cu/Cu2O/Ni composite catalysts for dye degradation.Crystal phase,surface element valence,morphology,light absorption range,recombination rate of photogenerated electron-hole pairs and dye degradation effect of Cu2O-Cu/Ni and Ag-Cu/Cu2O/Ni were respectively measured by X-ray diffraction(XRD),X-ray photoelectron spectra(XPS),Scanning electron microscope(SEM),UV-vis diffuses reflectance spectra(DRS),Photoluminescence spectra analysis(PL)and UV-vis spectrophotometer.By changing the amount of covered Cu on catalyst surface,calcination temperature and nitric acid pre-treatment concentration,the best condition was optimized for the growth of Cu2O nanowire.The result showed that there were lots of Cu2O nanowire evenly growing on catalyst surface when the condition was as follow:1.437g copper acetate were added,calcination temperature reached 350 °C and nitric acid pre-treatment concentration was 5%.By optimizing preparation condition of Ag-Cu/Cu2O/Ni,the result showed that A07 degradation effect reached 88.6%when the added amount of AgNO3 was 0.06g,hydrothermal temperature was 160 ?,the ratio of ethylene glycol and water was 50:20.By optimizing pH and reaction temperature,the result showed that it reached the best A07 degradation effect(94.3%)when the pH was in the range of 3-5 and reaction temperature was at 40 ?.A07 degradation mechanism in dark and visible light condition over Ag-Cu/Cu2O/Ni were studied as well.In darkness,a high standard reduction potential difference exists between Cu and Ag,Cu,as anode,tends to lose electrons and the electrons are spontaneously transferred to a higher potential(Ag electrode).Electrons in Ag will be immediately captured by O2,forming ·O2-,the dye pollutant can be decomposed to H2O and CO2 by ·O2-because of its super oxidability.In visible light condition,photogenerated electrons and holes are excited,the electrons could be swiftly transferred to Cu electrode as a result of schottky barrier at Cu2O/Cu interface?The potential difference are broadened when electrons are in Cu electrode,leading to the migration of electrons from Cu to Ag,which effectively curbs the recombination of photogenerated electrons and holes,so the prepared Ag-Cu/Cu2O/Ni catalyst exhibits excellent catalytic performance.Besides,the experimental results showed that the addition of triethanolamine(TEOA)obviously declined catalytic effect,indicating thath+ is the main active species.