Influence of TiO2 morphology on the photocatalytic efficiency of direct Z-scheme g-C3N4/TiO2 photocatalysts for isoniazid degradation
Influence of TiO2 morphology on the photocatalytic efficiency of direct Z-scheme g-C3N4/TiO2 photocatalysts for isoniazid degradation
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DOI：
10.1016/j.cej.2015.06.120
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发表时间：
2015-12-01
影响因子：
15.1
通讯作者：
Natarajan, Thillai Sivakumar
中科院分区：
文献类型：
--
作者：
Jo, Wan-Kuen;Natarajan, Thillai Sivakumar
采用湿浸渍法制备了不同g-C3N4负载量的直接Z型石墨化氮化碳（g-C3N4）/TiO2（纳米颗粒和纳米管）光催化剂。采用水热法合成了TiO2纳米管。以异烟肼为目标降解物，研究了TiO2形貌对直接Z型g-C3N4/TiO2光催化剂光催化效率的影响。采用粉末X射线粉末衍射、场发射扫描电子显微镜、透射电子显微镜、X射线光电子能谱和傅里叶变换红外光谱研究了g-C3N4和TiO2之间的牢固连接。随后，两种直接Z-方案的光催化剂用于异烟肼的分解。我们的研究结果表明，Z型g-C3N4/TiO2纳米管（3%-CN/TNT）光催化剂表现出增强的光催化活性，（90.8%，4 h）的光催化活性，并且g-C3N4/TiO2纳米颗粒（5%-CN/TNP）具有较高的活性（79.5%，4 h）比具有其他g-C3N4负载量、TiO 2纳米管（73.3%，4 h）、TiO 2纳米颗粒（56.3%，4 h）和g-C3N4（13.5%，4 h）的光催化剂更好。推测光催化活性的增强是由于通过Z-方案机制有效分离g-C3N4和TiO2之间的载流子。使用光致发光和光电流测量证实了载流子的分离。通过自由基（h（+）、（OH）-O-中心点和O-2（中心点-））清除和羟基（（OH）-O-中心点）自由基测定研究证实了直接Z-方案电荷转移过程。使用3%-CN/TNT光催化剂增强的（OH）-O-中心点自由基生成也可以导致比其他光催化剂增强的光催化性能。我们提出了一个机制，提高光催化活性和可能的降解途径异烟肼。使用动力学研究和化学需氧量分析进一步确认异烟肼降解。我们的研究结果表明，TiO2的形态显着影响的直接Z-计划的光催化剂在我们的反应条件下的光催化效率。(C)2015 Elsevier B.V.版权所有。
Direct Z-scheme graphitic carbon nitride (g-C3N4)/TiO2 (nanoparticle and nanotube) photocatalysts with different g-C3N4 loadings were prepared using a facile wetness impregnation method. TiO2 nanotubes were synthesized using a hydrothermal method. The influence of the TiO2 morphology on the photocatalytic efficiency of the direct Z-scheme g-C3N4/TiO2 photocatalysts was studied through the photodegradation of isoniazid. The firm connection between g-C3N4 and TiO2 was investigated using powder X-ray powder diffraction, field emission-scanning electron microscopy, transmission electron microscopy, X-ray photoelectron and Fourier-transform infrared spectroscopy. Subsequently, both the direct Z-scheme photocatalysts were used for the decomposition of isoniazid. Our results revealed that the Z-scheme g-C3N4/TiO2 nanotube (3%-CN/TNT) photocatalyst exhibited enhanced (90.8%, 4 h) photocatalytic activity, and the g-C3N4/TiO2 nanoparticles (5%-CN/TNP) had a higher activity (79.5%, 4 h) than the photocatalysts with other g-C3N4 loadings, TiO2 nanotubes (73.3%, 4 h), TiO2 nanoparticles (56.3%, 4 h), and g-C3N4 (13.5%, 4 h). Presumably the enhancement of photocatalytic activity was due to effective separation of the charge carriers between g-C3N4 and TiO2 through the Z-scheme mechanism. The separation of the charge carriers was confirmed using photoluminescence and photocurrent measurements. A direct Z-scheme charge transfer process was confirmed through free radicals (h(+), (OH)-O-center dot, and O-2(center dot-)) scavenging and hydroxyl ((OH)-O-center dot) radical determination studies. The enhanced (OH)-O-center dot radical generation using 3%-CN/TNT photocatalyst could also lead to enhanced photocatalytic performance than the other photocatalysts. We proposed a mechanism for the enhanced photocatalytic activity and the probable degradation pathway for isoniazid. Further confirmation of the isoniazid degradation was performed using kinetic studies and chemical oxygen demand analysis. Our results suggested that the TiO2 morphology significantly influenced the photocatalytic efficiency of the direct Z-scheme photocatalysts under our reaction conditions. (C) 2015 Elsevier B.V. All rights reserved.