Design,Preparation Of Bismuth-based Heterogeneous Junction Photocatalyst With High Quality Interface

Since the 21 st century,the problem of energy shortage and environmental pollution has become a key problem in restricting China's economic development.Photocatalytic technology is an effective solution to the current energy and environmental problems.As the heterogeneous structure of photocatalyst can effectively improve the photon quantum yield,inhibition of photo-generated electron-hole pairs of composite advantages,has been widely concerned.However,in practical studies,it has been found that although the heterojunction can effectively improve the photocatalytic activity,the stability is still poor(the loaded semiconductor is easy to fall off,the interface disappears,and the catalytic activity is deactivated after several times).This is mainly due to the quality of the junction interface is not high.The development of heterojunction photocatalyst with high interface quality is a hotspot in recent years.Therefore,in this paper,we mainly studied the synthesis and photocatalytic performance of bismuth-based heterojunction with high quality interface.The main research contents are as follows:1.Novel one-dimensional Bi2O3-Bi14MoO24 heterostructures with high interface quality were synthesized by high temperature calcining Bi2MoO6-Bi(OHC2O4)·2H2O precursors.Bi14MoO24 grew on the Bi2O3 porous rod by crystallographic-oriented epitaxial growth,which increases the interface quality and then provides the smallest penetration barrier for electron-hole pairs transfer between Bi2O3-Bi14MoO24 interfaces.The results show that Bi2O3-Bi14MoO24 heterostructure displays higher photocatalytic activity than pure phase Bi2O3 and Bi14MoO24,and 100% phenol(10 mg/L)can be degraded in 80 min under visible light irradiation using Bi2O3-Bi14MoO24(DS-2)heterostructure as photocatalyst.This enhanced photocatalytic performance is ascribed to the synergistic effect of the suitableband alignment of the Bi2O3 and Bi14MoO24,high interface quality and onedimensional ordered nanostructure.Radical scavenger experiments proved that the photogenerated holes and ·O2-play the key role during the photodegradation process.This work would offer an effective route to design and fabrication of junction structures with high interface quality for photocatalytic applications.2.Bi2O2CO3 nanosheets were prepared by hydrothermal method using Bi2O3 nanorods and urea as raw materials and cetyltriylammonium bromide(CTAB)as a surfactant.The experimental results show that Br-doped Bi2O2CO3 exhibits excellent photocatalytic activity for degradation of methyl orange(MO)and rhodamine B(RhB).Under the simulated sunlight,100%methyl orange(10 mg/L)and rhodamine B(10 mg/L)can be degraded in 12 min and 15 min under solar light irradiation using Br-doped Bi2O2CO3 as photocatalyst degraded,respectively.Significant photocatalytic performance is due to the synergistic effect of the following two factors:(1)Br-doped Bi2O2CO3 nanosheets,broadening the absorption range of light;(2)ultra-thin Bi2O2CO3 nanosheets provide carriers Shorter transmission path.Free radical scavenging experiments showed that superoxide radical(·O2-)and hole(h+)were the main active species of photocatalysis.This work will provide an effective design approach for the application of photocatalysts.3.Br-Bi2O2CO3-110-BiOI heterostructures has been synthesized by low temperature stirring method using Br-Bi2O2CO3 nanosheets as templates.BiOI nanosheets were grown vertically on the(110)plane of Br-Bi2O2CO3 nanosheets.100% MO(10 mg/L)can be degraded in 30 min under visible light irradiation using Br-Bi2O2CO3-110-Bi OI heterostructures(S2)as photocatalyst.Br-Bi2O2CO3-110-BiOI heterojunctions also have good photocatalytic activity for degradation of dyes(phenol and rhodamine B)under simulated sunlight.And its photocatalytic activity is better than that of single Br-Bi2O2CO3 nanosheet and BiOI nanosheets.This enhanced photocatalytic performance is ascribed to the synergistic effect of high interface quality and the formation of Br-Bi2O2CO3-110-BiOI heterojunctionon the(110)plane,which facilitates the rapid transfer of electrons excited by BiOI to the(110)plane of Br-Bi2O2CO3,Br-Bi2O2CO3 of the(110)plane is the electron-active surface.Radical scavenging experiments show that superoxide radical(·O2-)and hole(h+)are the main active species in photocatalysis.This work will provide an effective design approach in the application of photocatalysts.