光催化
材料科学
兴奋剂
铁电性
无机化学
催化作用
光电子学
化学
有机化学
电介质
作者
Jafar Hussain Shah,Afia Malik,Ahmed Mahmoud Idris,Saadia Rasheed,Hongxian Han,Can Li
出处
期刊:Chinese Journal of Catalysis
[China Science Publishing & Media Ltd.]
日期:2021-06-01
卷期号:42 (6): 945-952
被引量:22
标识
DOI:10.1016/s1872-2067(20)63713-5
摘要
The development of stable and efficient visible light-absorbing oxide-based semiconductor photocatalysts is a desirable task for solar water splitting applications. Recently, we proposed that the low photocurrent density in film-based BiFeO 3 (BFO) is due to charge recombination at the interface of the domain walls, which could be largely reduced in particulate photocatalyst systems. To demonstrate this hypothesis, in this work we synthesized particulate BFO and Mn-doped BiFeO 3 (Mn-BFO) by the sol-gel method. Photocatalytic water oxidation tests showed that pure BFO had an intrinsic photocatalytic oxygen evolution reaction (OER) activity of 70 μmol h -1 g -1 , while BFO-2, with an optimum amount of Mn doping (0.05%), showed an OER activity of 255 μmol h -1 g -1 under visible light ( λ ≥ 420 nm) irradiation. The bandgap of Mn-doped BFO could be reduced from 2.1 to 1.36 eV by varying the amount of Mn doping. Density functional theory (DFT) calculations suggested that surface Fe (rather than Mn) species serve as the active sites for water oxidation, because the overpotential for water oxidation on Fe species after Mn doping is 0.51 V, which is the lowest value measured for the different Fe and Mn species examined in this study. The improved photocatalytic water oxidation activity of Mn-BFO is ascribed to the synergistic effect of the bandgap narrowing, which increases the absorption of visible light, reduces the activation energy of water oxidation, and inhibits the recombination of photogenerated charges. This work demonstrates that Mn doping is an effective strategy to enhance the intrinsic photocatalytic water oxidation activity of particulate ferroelectric BFO photocatalysts. Mn-doped BiFeO 3 enhances intrinsic photocatalytic OER activity due to synergetic improvement of light absorption and charge separation as well as lowering the water oxidation activation energy.
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