| Lanthanum ferrite（La Fe O3）shows unique superiority in the fields of photovoltaic and catalysis due to its diversified morphology,variable oxidation state and defect structure and abundant physical and chemical properties.However,high recombination rate of photogenerated carrier in the process of photocatalytic degradation limits the utilization of La Fe O3.To further improve the photocatalytic performance of La Fe O3,electron acceptor and binary semiconductor composites were introduced to inhibit recombination of photogenerated electron-hole.The main details are summarized as follows:（1）Porous spherical La Fe O3oxide powders were synthesized by ultrasound-assisted glycerol solvothermal method to explore degradation activity of RB5 with the synergistic effect of perdisulfide（PDS）under 25 W UV irradiation.The results showed that the La Fe O3oxide powders with the particle size of 200 nm～1μm prepared in 50%glycerol solvent displayed the best catalytic degradation performance.The decolorization rate of RB5 within 50 min could reach 98.19%and the degradation rate of aromatic ring structure and COD were 43.92%and 75.24%,respectively.Radical quenching experiments showed that all of 1O2、SO4·-and·OH played roles in the catalytic degradation process.In the UV/PDS/La Fe O3system,the capture of photogenerated electrons by PDS promoted the separation of electron hole pairs of La Fe O3to some extent.Meanwhile,a large number of SO4·-were generated by means of stimulation for PDS by the transition metal element Fe as a catalyst.Therefore,under the synergistic effect of La Fe O3photocatalysis and advanced oxidation based on SO4·-radical,the degradation process of organic was further accelerated.（2）Based on the sheet Bi OCl prepared by low temperature alcohol hydrolysis,a series of La Fe O3/Bi OCl binary heterojunction photocatalytic materials were synthesized by dehydration and contraction method on the basis of spherical La Fe O3.The photocatalytic activity was evaluated by desorbing methylene blue（MB）,RB5 and rhodanine B（Rh B）under 300 W xenon lamp.The results indicated that the La Fe O3/Bi OCl with a mass ratio of3:7 exhibited the best visible light catalytic performance,and 95%of RB5 and Rh B could be removed within 70 min.The MB degradation rate merely decreased 9.70%after three cycles,indicating excellent photocatalytic stability of the composite material.Radical quenching experiments showed that the main active species involved in the reaction were·OH and 1O2.The binary heterojunction La Fe O3/Bi OCl induced transfer of photogenerated electron to the conduction band of Bi OCl,while photogenerated hole to the valence band of La Fe O3,resulting in the reduction and oxidation reactions respectively.Thus,a large number of active radicals with the ability of oxidation and degradation were generated. |
