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%.
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)
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).
