| Nowadays,photocatalytic degradation of dyes is one of the optimal technologies to solve the problems of environment and energy.As the typical example in BiOX（X=Cl,Br,I）photocatalysts,BiOI displays the excellent visible light response due to its narrow band gap（～1.7 eV）.However,the application in pollutant degradation has been limited by its fast recombination of e--h+pairs.Thus,it is urgent to reduce the recombination of e--h+pairs for expanding the application of BiOI.In this paper,the BiOI-based photocatalytic composites have successfully prepared using simple solvothermal synthesis,microwave-assisted synthesis and electro-spinning techniques in order to handle the issues in pollution degration.The main contents are as follows:1.Macroporous/mesoporous NiO/BiOI heterojunction（step-type）photocatalyst was prepared via solvothermal-calcination method by using Bi（NO3）3·5H2O and Ni（CH3COO）2-4H2O as the sources of Bi and Ni,respectively.The NiO/BiOI sample showed the remarkable performance of photodegration RhB(1x10-5 mol/L)under 300 W xenon lamp.The results suggested that the mass ratio of NiO in NiO/BiOI photocatalyst had a great effect on the photocatalytic performance.When the ratio of NiO to BiOI was 10%,the sample showed the best performance in RhB photodegradation.A S-scheme heterojunction mechanism was proposed to explain the enhanced photocatalytic performance of NiO/BiOI sample in the photodegradation of RhB.2.TiO2/BiOI heterojunction（p-n type）photocatalyst was successfully synthesized by simple electrostatic spinning and microwave-assisted synthesis technology using tetrabutyl titanate and Bi（NO3）3·5H2O as precursors.The photocatalytic performance of all samples was evaluated via photodegradation of 1 x 10-5 mol/L RhB aqueous solution under visible light（λ≥ 420 nm）at room temperature.The experimental results suggested that the mass ratio of TiO2 to BiOI had a great effect on the photocatalytic performance.When the mass ratio of TiO2 to BiOI was 20%,the k value was 53.3 x 10-3 min-1,which was 2.0 and 3.9 times than those of pure BiOI and pure TiO2,respectively.The capturing experiments results displayed that h+was the main active material and O2-was the secondary active material.A possible mechanism of the enhanced phtocatalytic activity of TiO2/BiOI sample was also proposed.3.Bi/BiOI composite photocatalyst was rapidly synthesized by simple microwave-assisted synthesis method using Bi（NO3）3·5H2O and ethylene glycol as the Bi source and reducing agent,respectively.The Bi element substance,as a channel for transporting electrons,effectively promoted the separation of e--h+pairs in BiOI The photocatalytic performance of Bi/BiOI flower sphere was evaluated via degradation of 1 x 10-5 mol/LRhB aqueous solution undervisible light（λ≥ 420 nm）at room temperature.Compared with pure BiOI,the Bi/BiOI composite showed greater photocalytic performance.When the loading of Bi was 20%,the Bi/BiOI showed the best performance.This is ascribed to the fact that Bi element had the SPR effect,which promoted the transfer of e-,thereby increasing the visible light response range of BiOI.In the degradation reaction for Bi/BiOI,the h+and·O2-were the main active substants,and·OH was secondary active substant. |
