Preparation And Photocatalytic Properties Of Pr-TiO₂/Ag₃PO₄ Nanomaterials

Semiconductor photocatalysis technology is a new way of efficient utilization of solar energy developed in recent years,which can use photon energy through catalysts to deeply degrade environmental pollutants,photolyse water to produce hydrogen,and reduce carbon dioxide,so there is a considerable application prospect in the field of energy,environment,and health,in which Ti O₂has become the most widely used photocatalyst due to its stable chemical properties,non-toxicity to organisms and good photocatalytic activity.However,the realistic application of Ti O₂usually encounters low visible light utilization and quantum efficiency,which immensely limits its further development in the area of photocatalysis.Aiming at the problem of low utilization of visible light,this work adopted the rare earth element praseodymium doping method to prepare praseodymium-doped Ti O₂nanomaterials（Pr-Ti O₂）.The research results demonstrated that the phases of the prepared Pr-Ti O₂were all anatase Ti O₂,and no related phase of praseodymium was observed;the Pr doping effectively inhibited the growth of Ti O₂grains,promoted the improvement of the specific surface area of the material,and broadened the visible light response scope of Ti O₂;in the Pr-Ti O₂system,Pr coexisted with+3 and+4 in the material,which can generate traps to capture photogenerated holes and elevate the effective separation of photogenerated electrons and holes;the photocatalytic degradation rate of Pr-Ti O₂prepared under the optimal process parameters of Pr doping content was 20%,hydrothermal temperature was 160°C,and hydrothermal time was 14 h for methyl orange solution was 98%within 120 min of photocatalytic reaction time.Aiming at the problem of low quantum efficiency,this work adopted the method of heterostructure construction to prepare Pr-Ti O₂/Ag₃PO₄nanocomposite materials,which facilitated the separation of electron and hole pairs and improves the quantum efficiency of Ti O₂.The results demonstrated that the phases of anatase Ti O₂and Ag₃PO₄coexisted in the composite material,and the related phase of praseodymium was not found.The material was composed of two kinds of microscopic particles with different densities,and the EDS surface scanning results showed that the dense and loose structure were Pr-Ti O₂and Ag₃PO₄,respectively.Compared with the XPS spectra of Ag₃PO₄and Pr-Ti O₂,it was found that the binding energy of Ag 3d in Pr-Ti O₂/Ag₃PO₄was shifted to the negative direction by 0.3 e V,and the binding energy of Ti 2p was shifted to the positive direction by 0.1 e V,indicating that there was a strong interaction between the Pr-Ti O₂and Ag₃PO₄heterointerfaces.The results of photocatalytic experiments showed that with the increase of Ag₃PO₄composite amount,the photocatalytic performance of Pr-Ti O₂/Ag₃PO₄demonstrated a trend of increasing first and then decreasing.When the composite amount of Ag₃PO₄was 25%,the photocatalytic performance of Pr-Ti O₂/Ag₃PO₄was optimal.Through the photocatalytic cycle test,Pr-Ti O₂/Ag₃PO₄had higher photostability,and when this photocatalyst was cycled 3 times,the photocatalytic degradation rate of Pr-Ti O₂/Ag₃PO₄was still more than 80%.