Synthesis Of Cu/N-UiO Composite Matetials And Their Visible-light-driven Photocatalytic Properties

At present,the photocatalytic reactivity of metal-organic frameworks（MOFs）which have been found is very low,especially under the visible light irradiation.Therefore,effective CO₂ capture and activation is a prerequisite step for highly efficient CO₂ reduction.Based on the previous studies,it is proved that Cu can effectively activate CO₂,and reduce the energy barrier of CO₂ reduction under the visible light.In this experiment,we intend to prepare Cu/NH₂-UiO-66（Cu/N-UiO）composite photocatalyst to study the effect of Cu on CO₂ reduction under the visible light irradiation.In this experiment,we prepare N-UiO with H₂ATA and ZrCl₄ as raw materials,by the solvothermal method.The thermal stability of most MOFs is worse than that of ordinary semiconductor photocatalysts.The preparation of Cu-modified Ni-UiO is based on the method of Duff and Baiker,using THPC as reductant and stabilizer achieving loading metal Cu on the surface of N-UiO,preventing destroying N-UiO structure from high temperature.The prepared sample was characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,UV-Vis spectroscopy,X-ray photoelectron spectroscopy（XPS）,fluorescence spectroscopy and nitrogen adsorption-desorption.The photocatalytic activity of Cu/N-UiO was evaluated by reduction of CO₂ under irradiation of visible light.The photocatalytic activity of Cu/N-UiO prepared by D.B.method was high and showed high selectivity of products,only generating syngas consisting by CO and H₂.In addition,in this experiment,metal Pt,Au,Ir,Pd and Rh were loaded on the surface of N-UiO were compared with Cu/N-Ui O on the photocatalytic and photoelectrochemical properties.Cu/N-UiO（D.B.）exhibited the best photocatalytic and photoelectrical properties.It has been found that Cu could not only effectively converge electrons,inhibit the recombination of photo-generated electrons and holes,but also effectively activate CO₂,reducing the barrier potential of CO₂ reduction reaction,leading to the improved photocatalytic activity.