软铋矿Bi_(12)MnO_(20)的制备及利用超氧自由基提升其去除有机污染物光催化活性  

Preparation of sillenite-type Bi_(12)MnO_(20) with enhanced photocatalytic activity for removal of organic pollutants via superoxide radicals

作　　者：湛菁 王焕伟 李启厚 王志坚 房鑫 Jing ZHAN;Huan-wei WANG;Qi-hou LI;Zhi-jian WANG;Xin FANG(School of Metallurgy and Environment,Central South University,Changsha 410083,China;Hunan Rare Earth Metal Material Research Institute,Changsha 410083,China)

机构地区：[1]中南大学冶金与环境学院,长沙410083 [2]湖南稀土金属材料研究院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第11期3570-3582,共13页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51974378);the Natural Science Foundation of Hunan province,China(No.2020JJ4735);the Hunan Key Laboratory for Rare Earth Functional Materials,China(No.2017TP1031).

摘　　要：通过湿法球磨联合煅烧方法制备软铋矿型光催化材料Bi_(12)MnO_(20),其光吸收能力覆盖200~2200nm光谱范围。Bi_(12)MnO_(20)的晶体结构可以视为Mn^(4+)掺入到亚稳立方γ-Bi_(2)O_(3)的四面体中所得,并且Bi_(12)MnO_(20)的能带结构中出现禁带宽度为1.25eV的子带隙。这种能带结构的优化有利于Bi_(12)MnO_(20)光催化剂加速转化溶液中O_(2)为超氧自由基(·O_(2)^(-)),以改善光催化降解过程中的电荷分离和转移。结果表明,在模拟阳光照射下,Bi_(12)MnO_(20)对pH8溶液中浓度为10mg/L的孔雀石绿降解率达到95%以上。经过4次光降解实验后,Bi_(12)MnO_(20)对孔雀石绿的降解率保持在74.9%。Sillenite-type photocatalytic material Bi_(12)MnO_(20) with photo-absorptive ability in the spectrum range of 200-2200 nm was prepared by wet ball milling followed by calcination.The crystal structure of Bi_(12)MnO_(20) can be viewed as the metastable cubicγ-Bi_(2)O_(3) with the incorporation of Mn^(4+) into tetrahedral sites.The entry of Mn^(4+) intoγ-Bi_(2)O_(3) crystal creates a sub-bandgap of 1.25 eV appearing in the energy band structure of Bi_(12)MnO_(20).The Bi_(12)MnO_(20) photocatalyst can accelerate the transformation of O_(2) in solution into superoxide radicals(·O_(2)^(-)),thereby improving charge separation and transfer during photocatalytic degradation.As a result,the degradation rate of over 95%to the malachite green(MG)with a concentration of 10 mg/L in the pH=8 solution by Bi_(12)MnO_(20) is achieved under simulated sunlight.After four cycles of photo-degradation,the removal rate of MG by Bi_(12)MnO_(20) remains at 74.9%.

关 键 词：Bi_(12)MnO_(20) 光催化 降解 能带 超氧自由基 

分 类 号：X703[环境科学与工程—环境工程] O644.1[理学—物理化学] O643.36[理学—化学]