Direct Z-Scheme Water Splitting Photocatalyst Based on Two-Dimensional Van Der Waals Heterostructures.
Direct Z-Scheme Water Splitting Photocatalyst Based on Two-Dimensional Van Der Waals Heterostructures.
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DOI：
10.1021/acs.jpclett.8b02369
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
Ruiqi Zhang;Lili Zhang;Qijing Zheng;P. Gao;Jin Zhao;Jinlong Yang
中科院分区：
文献类型：
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作者：
Ruiqi Zhang;Lili Zhang;Qijing Zheng;P. Gao;Jin Zhao;Jinlong Yang
模拟植物的光合作用，Z型水分解是一种很有前途的提高光催化活性的策略。直接Z型光催化剂的研究具有重要意义，而影响光催化效率的关键因素是两个光系统界面处的光生电子-空穴复合速率。基于含时从头算非绝热分子动力学（NAMD）方法，我们首次报道了一种由单层BCN和C2 N组成的二维无金属货车德瓦耳斯（vdW）异质结构，该异质结构有望作为直接Z型光催化剂用于水裂解.结果表明，BCN/C2 N的电子-电子复合时间尺度在2 ps以内。在这些电子-氢复合事件中，85%以上是通过界面处的电子-氢复合。基于冻结声子方法的NAMD模拟证明了这种超快层间e-h复合是由层内光学声子模和vdW相互作用诱导的层间剪切声子模辅助的。在这些关键的声子模式，层间的相对运动，缺乏传统的异质结构与强相互作用，但普遍存在于各种二维vdW异质结构，是显着的。我们的研究结果表明，二维vdW异质结构家族是令人信服的一种新型的直接Z计划的光催化剂的搜索。
Mimicking the natural photosynthesis in plants, Z-scheme water splitting is a promising strategy to improve photocatalytic activity. Searching for the direct Z-scheme photocatalysts is urgent and the crucial factor for the photocatalytic efficiency is the photogenerated electron-hole ( e-h) recombination rate at the interface of two photosystems. In this report, based on time-dependent ab initio nonadiabatic molecular dynamics (NAMD) investigation, we first report a two-dimensional (2D) metal-free van der Waals (vdW) heterostructure consisting of monolayer BCN and C2N as a promising candidate for direct Z-scheme photocatalysts for water splitting. It is shown that the time scale of e-h recombination of BCN/C2N is within 2 ps. Among such e-h recombination events, more than 85% are through the e-h recombination at the interface. NAMD simulations based on frozen phonon method prove that such an ultrafast interlayer e-h recombination is assisted by intralayer optical phonon modes and the interlayer shear phonon mode induced by vdW interaction. In these crucial phonon modes, the interlayer relative movements which are lacking in traditional heterostructures with strong interactions, yet exist generally in various 2D vdW heterostructures, are significant. Our results prove that the 2D vdW heterostructure family is convincing for a new type of direct Z-scheme photocatalysts searching.