Effect of halogen atoms on photocatalytic activity of bismuth oxyhalide (BIOX, X = Cl, Br, I)
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摘要: 利用水热法和溶剂热法制备了BiOCl、BiOBr和BiOI三种光催化剂,通过XRD、SEM、光电流密度与UV-vis DRS表征了光催化剂的晶体结构、表面形貌与光电性能,DFT计算结果表明,随着卤素原子序数升高,光催化剂导带附近的费米能级的分散度降低,禁带宽度变小。在可见光照射下,通过水溶液中罗丹明B的降解效果来评价光催化剂的光催化活性,BiOI具有最好的光催化活性,60 min内,罗丹明B的降解效率达到100%,同时通过自由基捕获实验探究了卤氧化铋光催化降解过程的主要活性基团。Abstract: BiOCl, BiOBr and BiOI were prepared by hydrothermal and solvothermal methods. XRD, SEM, photocurrent density curve and UV-vis were used to characterize the crystal structure, surface morphology and photoelectric properties. The band structure and density of states of BiOX were calculated by DFT. With the atomic number of halogen increase, the dispersion of the Fermi level near the semiconductor conduction band decreases, and the band gap becomes smaller. The photocatalytic activity of BiOCl, BiOBr and BiOI was evaluated by photocatalytic degradation of Rhodamine B (RhB), and the degradation rate of RhB in 60 min for BiOI could reach 100%. Meanwhile, the main active groups in the process of photocatalytic degradation of RhB were explored by radical trapping experiment.
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Key words:
- BiOX /
- halogen atom /
- photocatalysis /
- photocatalytic performance
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表 1 BiOBr、BiOCl和BiOI的一级反应动力学参数
Table 1 First-order reaction kinetic parameters of BiOBr, BiOCl and BiOI
Sample BiOBr BiOCl BiOI k/min−1 0.010 0.0188 0.0649 R2 0.982 0.993 0.997 -
[1] FENG X F, YU Z X, SUN Y X, LONG RX, SHAN M Y, LI X H, LIU Y C, LIU J H. Review MXenes as a new type of nanomaterial for environmental applications in the photocatalytic degradation of water pollutants[J]. Ceram Int,2020,47(6):7321−7343. [2] 祝泽周. 界面位点调控光/电催化CO2还原性能研究[D]. 合肥: 中国科学技术大学, 2020.ZHU Ze-zhou. Engineering the interface sites for photocatalytic/electrocatalytic CO2 reduction[D]. Hefei: University of Science and Technology of China, 2020. [3] AHMAD K, GHATAK H R, AHUJA S M. A review on photocatalytic remediation of environmental pollutants and H2 production through water splitting: A sustainable approach[J]. Environ Technol Innovation,2020,19:100893. [4] FUJISHIMA, A., HONDA, K. Photolysis of water at a semiconductor electrode[J]. Nature,1972,238:37−38. doi: 10.1038/238037a0 [5] 杨帆. 氧化钛复合材料的结构精确调控及其光催化性能研究[D]. 合肥: 中国科学技术大学, 2020.YANG Fan. Precise structure control of TiO2 composite materials and its photocatalytic performance[D]. Hefei: University of Science and Technology of China, 2020. [6] HUANG X J, GUO Q B, YAN B C, LIU H, CHEN K, WEI S S, WU Y H, WANG L. Study on photocatalytic degradation of phenol by BiOI/Bi2WO6 layered heterojunction synthesized by hydrothermal method[J]. J Mol Liq,2021,322:114965. doi: 10.1016/j.molliq.2020.114965 [7] LIU H J, WANG B J, CHEN M, ZHANG H, PENG J B, DING L, WANG W F. Simple synthesis of BiOAc/BiOBr heterojunction composites for the efficient photocatalytic removal of organic pollutants[J]. Sep Purif Technol,2021,261:118286. doi: 10.1016/j.seppur.2020.118286 [8] MOKHTARI F, TAHMASEBI N. Hydrothermal synthesis of W-doped BiOCl nanoplates for photocatalytic degradation of rhodamine B under visible light[J]. J Phys Chem Solids,2021,149:109804. doi: 10.1016/j.jpcs.2020.109804 [9] WANG Y, SUNARSO J, ZHAO B, GE C H, CHNE G H. One-dimensional BiOBr nanosheets/TiO2 nanofibers composite: Controllable synthesis and enhanced visible photocatalytic activity[J]. Ceram Int,2017,43(17):15769−15776. doi: 10.1016/j.ceramint.2017.08.140 [10] YE L Q, JIN X L, LENG Y M, SU Y R, XIE H Q, LIU C. Synthesis of black ultrathin BiOCl nanosheets for efficient photocatalytic H2 production under visible light irradiation[J]. J Power Sources,2015,293:409−415. doi: 10.1016/j.jpowsour.2015.05.101 [11] CUI Y H, YANG L L, ZHENG J, WANG Z K, LI B R, YAN Y, MENG M J. Synergistic interaction of Z-scheme 2D/3D g-C3N4/BiOI heterojunction and porous PVDF membrane for greatly improving the photodegradation efficiency of tetracycline[J]. J Colloid Interf Sci,2021,586:335−348. doi: 10.1016/j.jcis.2020.10.097 [12] BARHOUMI M, SAID M. Correction of band-gap energy and dielectric function of BiOX bulk with GW and BSE[J]. Optik,2020,216:164631. doi: 10.1016/j.ijleo.2020.164631 [13] YE L Q, DENG K J, XU F, TIAN LH, PENG T Y, ZAN L. Increasing visible-light absorption for photocatalysis with black BiOCl[J]. Chem Chem Phys, 2012, 14: 82–85.