Controllable Synthesis of Mesoporous TiO2 Polymorphs with Tunable Crystal Structure for Enhanced Photocatalytic H2 Production
Controllable Synthesis of Mesoporous TiO2 Polymorphs with Tunable Crystal Structure for Enhanced Photocatalytic H2 Production
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可控合成具有可调晶体结构的介孔 TiO2 多晶型物以增强光催化 H-2 生产
DOI：
10.1002/aenm.201901634
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发表时间：
2019-08-01
影响因子：
27.8
通讯作者：
Zhang, Hongjie
中科院分区：
文献类型：
--
作者：
Xiong, Hailong;Wu, Lanlan;Zhang, Hongjie
多相二氧化钛（TiO 2）具有丰富的异质结，已被广泛用于各种光催化应用。目前多相TiO 2的合成主要涉及热处理和多步剧烈反应过程，不利于控制多相TiO 2的晶相和相比。同时，所得产物具有相对低的表面积和无孔结构。在这里，一个简单的聚合物辅助的配位介导的自组装方法，合成介孔TiO 2多晶型可控异相结和大表面积，通过使用聚乙烯亚胺作为致孔剂在酸性水合成系统的报告。使用这种方法，通过选择合适的酸性介质，可以很容易地定制晶相（三相、双相和单相）和相组成（0-100%）。此外，比表面积（77-228 m（2）g（-1））和孔径（2.9-10.1 nm）容易通过改变反应温度来定制。通过光催化析氢反应评价了介孔TiO 2多晶型物的光催化活性。与其他多晶型物相比，三相TiO 2表现出优异的光催化H-2产生速率为3.57 mmol h（-1）g（-1），这归因于异相结和介观结构的协同效应。还阐明了三相TiO_2可能的电子转移途径的能带图。
Multiphasic titanium dioxide (TiO2) possessing abundant heterophase junctions have been widely used for various photocatalytic applications. Current synthesis of multiphasic TiO2 mainly involves the process of thermal treatment and multiple steps of rigorous reactions, which is adverse to controlling the crystal phases and phase ratios of multiphasic TiO2. Meanwhile, the resulting products have relatively low surface area and nonporous structure. Here, a facile polymer-assisted coordination-mediated self-assembly method to synthesize mesoporous TiO2 polymorphs with controllable heterophase junctions and large surface area by using polyethylenimine as the porogen in an acidic aqueous synthesis system is reported. Using this approach, the crystal phases (triphase, biphase, and monophase) and phase compositions (0-100%) are easily tailored by selecting the suitable acidic media. Furthermore, the specific surface areas (77-228 m(2) g(-1)) and pore sizes (2.9-10.1 nm) are readily tailored by changing the reaction temperature. The photocatalytic activity of mesoporous TiO2 polymorphs is evaluated by photocatalytic hydrogen evolution. The triphasic TiO2 exhibits an excellent photocatalytic H-2 generation rate of 3.57 mmol h(-1) g(-1) as compared to other polymorphs, which is attributed to the synergistic effects of heterophase junctions and mesostructure. The band diagram of possible electron transfer pathway for triphasic TiO2 is also elucidated.