Ultra-small freestanding amorphous molybdenum sulfide colloidal nanodots for highly efficient photocatalytic hydrogen evolution reaction
Ultra-small freestanding amorphous molybdenum sulfide colloidal nanodots for highly efficient photocatalytic hydrogen evolution reaction
复制标题
用于高效光催化析氢反应的超小型独立式非晶硫化钼胶体纳米点
DOI：
10.1016/j.apcatb.2018.03.087
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发表时间：
2018-09-15
期刊：
影响因子：
--
通讯作者：
Ye, Jinhua
中科院分区：
文献类型：
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作者：
Chang, Kun;Pang, Hong;Ye, Jinhua
近年来，硫化钼及其无定形化合物具有比析氢反应(HER)更高的活性，使其成为开发新的HER催化剂的高潜力材料。本文介绍了一种简便的化学方法合成直径小于2 nm的无定形无定形硫化钼(a-MOSX)超小胶体纳米点。电催化HER测试表明，与原位热处理的c-MoS_2相比，独立的a-Mosx胶体纳米点在STARK中表现出更高的催化氢活性。将超小的α-MOX纳米点应用于光催化HER，在双功能分子连接剂的辅助下，可以与二氧化钛形成紧密的界面，这有助于降低两组分之间的界面肖特基势垒，并允许从光收集器向共催化剂中快速注入光激电子。研究结果表明，α-MoSx@MPaTiO2光催化氢气提升率的显著提高主要是由HER过程中原位还原生成的不饱和Mo(IV)活性中心提供的。生成的不饱和Mo(IV)位的协同效应和更多暴露的本征活性边的存在进一步促进了a-Mosx纳米点上催化H-2活性的提高。
Recently, molybdenum sulfide with its amorphous counterpart was found to hold a high activity versus the hydrogen evolution reaction (HER), making it a high potential material to explore new HER catalysts. Here we present a facile chemical method to synthesize ultra-small freestanding amorphous molybdenum sulfide (a-MoSx) colloidal nanodots with diameter of lower than 2 nm. Electrocatalytic HER tests show that freestanding a-MoSx colloidal nanodots exhibit an enhanced catalytic hydrogen activity in stark in contrast with in-situ annealed c-MoS2. When applied as a co-catalyst in photocatalytic HER, ultra-small a-MoSx nanodots could form a compact interface with the TiO2 when assisted by a bifunctional molecular linker, as the mercaptopropionic acid (MPA), which facilitates the decrease of the interfacial Schottky barrier occurring between the two components and allows for a fast injection of photo-excited electrons from the photoharvester into the co-catalyst. Our results demonstrate that the drastic enhancement of the photocatalytic H-2 promotion rate of a-MoSx@MPA-TiO2 is mainly provided by unsaturated Mo(IV) active sites generated by the in-situ reduction during the photocatalytic HER process. The synergistic effect of generated unsaturated Mo(IV) sites and the presence of more exposed intrinsic active edges further promotes the enhancement of the catalytic H-2 activity on a-MoSx nanodots.