Solar light driven photoelectrocatalytic hydrogen evolution and dye degradation by metal-free few-layer MoS2 nanoflower/TiO2(B) nanobelts heterostructure
Solar light driven photoelectrocatalytic hydrogen evolution and dye degradation by metal-free few-layer MoS2 nanoflower/TiO2(B) nanobelts heterostructure
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DOI：
10.1016/j.solmat.2018.05.056
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发表时间：
2018-10-01
影响因子：
6.9
通讯作者：
Giri, P. K.
中科院分区：
文献类型：
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作者：
Paul, Kamal Kumar;Sreekanth, N.;Giri, P. K.
合理设计无金属分层纳米结构对于实现下一代光催化系统至关重要。过渡金属二硫属化物，例如具有形状控制的TiO2的基于MoS2的异质结构（HS），由于其独特的晶体结构、形貌和化学性质，在可见光电催化领域引起了极大的关注。在此，我们展示了在多孔 TiO2(B) 纳米带 (NB) 上低温溶剂热生长几层 MoS2 纳米花 (NF)，以增强酸性介质中的析氢反应 (HER)，以及改善有机染料罗丹明-B (RhB) 在可见光下的光催化降解。高分辨率 TEM 成像显示，横向尺寸为 130-350 nm 的少层 MoS2 NF 已成功在 TiO2 NB 上生长。 EDS 映射确认了 HS 样品中的元素组成及其空间分布。 MoS2/TiO2 NBs HS在黑暗下表现出极高的吸附能力（40分钟后66％），并且在可见光照射下对RhB具有增强的光催化降解效率（60分钟后80％）。系统的光电化学测量表明，MoS2/TiO2 NBs HS在酸性电解质中表现出优异的HER活性，具有过电势，在10 mA/cm(2)和95 mV/dec时估计塔菲尔斜率分别为-320 mV，远低于可见光下测量的原始TiO2 NBs的分别为-792 mV和135 mV/dec。结果表明，Volmer-Heyrovsky 机制导致在多孔 TiO2 NB 上边缘缺陷富集的少层 MoS2 制成的工作电极上产生极高的氢气。
A rational design of metal-free hierarchical nanostructures is critical for achieving next-generation photo catalytic system. Transition metal dichalcogenide, e.g., MoS2 based heterostructures (HSs) with shape-controlled TiO2 have attracted great attention in visible light electrocatalysis owing to their unique crystal structure, morphology and chemical properties. Herein, we demonstrate a low temperature solvothermal growth of few layer MoS2 nanoflowers (NFs) over the porous TiO2(B) nanobelts (NBs) for enhanced hydrogen evolution reaction (HER) in acidic media as well as improved photocatalytic degradation of organic dye rhodamine-B (RhB) under visible light. Few-layer MoS2 NFs with lateral sizes 130-350 nm were successfully grown on TiO2 NBs, as revealed from the high resolution TEM imaging. EDS mapping confirms the elemental composition and their spatial distribution in the HS sample. MoS2/TiO2 NBs HS exhibits extremely high adsorption ability (66% after 40 min) under dark as well as enhanced photocatalytic degradation efficiency (80% after 60 min) of RhB under visible light irradiation. A systematic photoelectrochemical measurements demonstrate that the MoS2/TiO2 NBs HS exhibits excellent HER activity in acidic electrolyte with an overpotential and estimated Tafel slope to be -320 mV at 10 mA/cm(2) and 95 mV/dec, respectively, which is much lower than that of the pristine TiO2 NBs measured to be-792 mV and 135 mV/dec, respectively, under visible light. It is shown that the Volmer-Heyrovsky mechanism leads to the extremely high hydrogen generation at the working electrode made with edge-defect enriched few layer MoS2 on porous TiO2 NBs.