Two-dimensional H-TiO2/MoS2(WS2) van der Waals heterostructures for visible-light photocatalysis and energy conversion
Two-dimensional H-TiO2/MoS2(WS2) van der Waals heterostructures for visible-light photocatalysis and energy conversion
复制标题
用于可见光光催化和能量转换的二维H-TiO2/MoS2(WS2)范德华异质结构
DOI：
10.1016/j.apsusc.2019.144425
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发表时间：
2019
影响因子：
6.7
通讯作者：
Wang Ling Ling
中科院分区：
文献类型：
--
作者：
Xiao Wen Zhi;Xu Liang;Rong Qing Yan;Dai Xiong Ying;Cheng Chuan Pin;Wang Ling Ling
二氧化钛（TiO2）由于其低廉的成本、优异的导电性和优异的电化学活性，在光催化和能量转换器件中有着广阔的应用前景。然而，它的大带隙和表面尺寸不足阻碍了它在可见光辐射下的应用，因此设计一个高效的二氧化钛电极结构是一个挑战。在此，我们使用二维六边形TiO2（H-TiO2）和二维MoS2（WS2）组分构建了新的范德华（vdW）异质结构。通过密度泛函理论，我们发现二维h - tio2具有强大的能量和力学稳定性，并且比石墨烯和MoS2具有更高的延展性。估算的间接带隙在4.30 ~ 4.62 eV之间，几乎没有可见光吸收。MoS2/ tio2和WS2/ tio2的vdW异质结构具有以下特点：直接带隙，ii型带对准，内置电子场，迁移率与MoS2（WS2）一样高，并且显著提高了可见光吸收。这些特点使异质结构具有很高的光催化性能和太阳能到电力的转换效率。因此，这些材料在光催化水分解和太阳能转换装置中具有很高的应用潜力。
Titanium dioxide (TiO2) has promising applications in photocatalysis and energy-conversion devices due to its low cost, outstanding conductivity, and excellent electrochemical activity. However, its large band gap and insufficient-sized surface hinder its applications under visible-light radiation, so designing a highly efficient TiO2-based electrode structure is challenging. Herein, we constructed novel van der Waals (vdW) heterostructures using two-dimensional hexagonal TiO2(H-TiO2) and 2D MoS2(WS2) components. By density functional theory, we found that the 2D H-TiO2has robust stability in energy and mechanics, as well as higher ductility than graphene and MoS2. The estimated indirect band gap ranged within 4.30–4.62 eV, resulting in hardly any visible-light absorbance. The vdW heterostructures of MoS2/TiO2and WS2/TiO2had the following characteristics: direct band gap, type-II band alignment, built-in electronic field, mobility as high as that of MoS2(WS2), and remarkably improved visible-light absorption. These features enabled the heterostructures to have highly improved photocatalytic performance and solar-to-electric power conversion efficiency. Thus, these materials have high potential application in photocatalytic water splitting and solar energy-conversion devices.