Hybridization of Nanodiamond and CuFe-LDH as Heterogeneous Photoactivator for Visible-Light Driven Photo-Fenton Reaction: Photocatalytic Activity and Mechanism
Hybridization of Nanodiamond and CuFe-LDH as Heterogeneous Photoactivator for Visible-Light Driven Photo-Fenton Reaction: Photocatalytic Activity and Mechanism
复制标题
纳米金刚石和 CuFe-LDH 的杂化作为可见光驱动光芬顿反应的异相光活化剂：光催化活性和机制
DOI：
10.3390/catal9020118
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发表时间：
2019-02-01
期刊：
影响因子：
3.9
通讯作者：
Li, Hongdong
中科院分区：
文献类型：
--
作者：
Liu, Lu;Li, Shijun;Li, Hongdong
建立两种半导体催化剂的异质结是提高光催化活性的一种很有前途的方法。本研究利用共沉淀法将纳米金刚石（ND）与铜铁层状双氢氧化物（LDH）杂化，作为一种新型的异质结来光活化H2 O2。结果表明，ND/LDH具有类水滑石结构，比表面积大（S-BET = 99.16m2/g），可见光吸收强，带隙低（E-g = 0.94eV）。在ND/LDH投加量为0.0667 g/L、H2 O2浓度为19.6 mmol/L、初始pH值不调的条件下，10 mg/L亚甲基蓝（MB）在120 min内降解率为93.5%，而LDH代替ND/LDH时，MB的降解率仅为78.3%。ND/LDH表现出优异的稳定性，并保持相对较高的活性，足以光活化H2 O2，即使在5个循环后。机理研究表明，在ND/LDH异质结中，从LDH（Cu/Fe 3d t（2g））价带转移到LDH（Cu/Fe 3d e（g））导带的光电子能自发迁移到ND导带，促进了光生电荷的分离.因此，光电子有足够的时间来加速Cu 3 +/Cu 2+和Fe 3 +/Fe 2+的氧化还原循环，以光活化H2 O2产生羟基自由基，导致优异的光Fenton降解MB的效率。
Establishing a heterojunction for two kinds of semiconductor catalysts is a promising way to enhance photocatalytic activity. In this study, nanodiamond (ND) and CuFe-layered double hydroxide (LDH) were hybridized by a simple coprecipitation method as a novel heterojunction to photoactivate H2O2. The ND/LDH possessed a hydrotalcite-like structure, large specific surface area (S-BET = 99.16 m(2)/g), strong absorption of visible-light and low band gap (E-g = 0.94 eV). Under the conditions of ND/LDH dosage 0.0667 g/L, H2O2 concentration 19.6 mmol/L, and without initial pH adjustment, 93.5% of 10 mg/L methylene blue (MB) was degraded within 120 min, while only 78.3% of MB was degraded in the presence of LDH instead of ND/LDH. The ND/LDH exhibited excellent stability and maintained relatively high activity, sufficient to photoactivate H2O2 even after five recycles. The mechanism study revealed that in the heterojunction of ND/LDH, the photoelectrons transferred from the valence band of LDH (Cu/Fe 3d t(2g)) to the conduction band of LDH (Cu/Fe 3d e(g)) could spontaneously migrate onto the conduction band of ND, promoting the separation of photo-induced charges. Thus, the photoelectrons had sufficient time to accelerate the redox cycles of Cu3+/Cu2+ and Fe3+/Fe2+ to photoactivate H2O2 to produce hydroxyl radicals, resulting in excellent photo-Fenton efficiency on MB degradation.