铋基金属有机骨架合成多孔炭负载Bi2O3/Bi三元可见光催化剂用于高效去除水中有机污染物

Preparation of visible-light photocatalysts of Bi2O3/Bi embedded in porous carbon from Bi-based metal organic frameworks for highly efficient Rhodamine B removal from water

利用高温碳化铋基金属有机骨架CAU-17(Bi)得到一系列不同炭化温度的多孔炭负载Bi2O3/Bi三元可见光催化材料(Bi2O3/Bi/PC),并对材料进行了详细的鉴定和表征。随后,通过在可见光下降解水中罗丹明B染料研究材料的光催化性能。结果表明,通过改变炭化温度可以调节三元光催化材料中的Bi2O3与Bi的比例。在炭化温度为800℃时,Bi2O3/Bi/PC表现出最高的光催化活性。同时,在降解罗丹明B的过程中,材料的3个组分表现出良好的协同效应,并且光催化材料在较宽的pH范围内均表现出良好的光催化活性。在光催化过程中,空穴和超氧自由基作为主要的活性物种主导污染物的降解。本研究通过高温炭化将金属有机骨架直接转化为三元光催化材料,为可用于高效降解水中有机污染物的可见光催化材料的设计与合成提供了新思路。

A series of ternary composite photocatalysts of Bi2O3/Bi embedded in porous carbon(Bi2O3/Bi/PC)was prepared by the high-temperature pyrolysis of a bismuth-based metal organic framework(CAU-17(Bi)).They were used as photocatalysts for the degradation of organic Rhodamine B dye(RhB)in water under visible light.Results showed that the Bi2O3/Bi/PC composites with different Bi2O3/Bi ratios could be obtained through changing the extent of the carbothermal reduction of Bi2O3 during pyrolysis.The photocatalyst pyrolyzed at 800 ℃ showed the highest photocatalytic performance and had a wide applicable pH value range and excellent recyclability and stability.The components in the ternary composites exhibited a synergetic effect in the remova l of RhB,where Bi2O3 acted as a low-band gap semiconductor,metallic Bi transferred electrons generated by visible light excitation to the graphitic structure in porous carbon to inhibit the recombination of electrons with holes.The holes and peroxide radicals were the main active species.This study provides a new way for the design and preparation of visible-light active and high-performance photocatalysts for organic contaminant degradation in aqueous media by using metal organic frameworks as a multicomponent precursor.