We have demonstrated an ultrahigh degradation activity of the single-layer and few-layered MoSe₂ nanoflowers for decomposing the Rhodamine (RhB) dye by the piezo-catalyst effect. The MoSe₂ nanoflowers can successfully decompose the RhB dye by 90% in 30 s through the application of the mechanical force (e.g., ultrasonic vibration) in dark. The size of the MoSe₂ nanoflowers has a diameter of less than 3 µm, which exhibits a great number of the single- and few-layers with a plentiful amount of active surface sites. The interlayer spacing between each single-layer MoSe₂ is ~ 0.67 nm. The piezoresponse force microscopy (PFM), and the tunneling atomic force microscopy (TUNA), further evidence that the MoSe₂ nanoflowers exhibit a significantly piezoelectric potential as created by the internal electric fields in different polarization domains of the single- and few-layered MoSe₂. The observed k_obs rate constant is 0.3 (ppm s⁻¹) with an ultra-fast degradation rate of ~ 69,889 ppm L mole⁻¹ s⁻¹. This is the fastest degradation rate in the dark among all reported catalysts. A redox process of the MoSe₂ nanoflowers as induced by mechanical force in dark have been evidenced by XPS spectra. The electron paramagnetic resonance (EPR) spin trapping with 5,5-dimethylpyrroline-1-oxide (DMPO) spectra indeed demonstrated the formation of the hydroxyl radical from the MoSe₂ nanoflowers during the ultrasonic vibration in dark, which is the major reactive oxygen species (ROS) for destroying the dye molecules. This is first work to demonstrate the very efficient catalyst and redox processes by piezo-catalyst effect using the MoSe₂ nanoflowers.

我们已经证明了单层和几层MoSe ₂纳米花的超高降解活性，可以通过压电催化剂作用分解罗丹明（RhB）染料。通过在黑暗中施加机械力（例如超声振动），MoSe ₂纳米花可以在30 s内成功地将RhB染料分解90％。MoSe ₂纳米花的大小具有小于3 µm的直径，它表现出大量的单层和少数层，并具有大量的活性表面位点。每个单层MoSe ₂之间的层间距为〜0.67 nm。压电响应力显微镜（PFM）和隧道原子力显微镜（TUNA）进一步证明了MoSe ₂纳米花表现出显着的压电势，这是由单层和少数MoSe _2的不同极化域中的内部电场产生的。观察到的k _obs速率常数为0.3（ppm s ^-1），超快降解速率为〜69,889 ppm Lmol ^-1  s ^-1。在所有报道的催化剂中，这是在黑暗中最快的降解速率。XPS光谱证明了在黑暗中由机械力诱导的MoSe ₂纳米花的氧化还原过程。5,5-二甲基吡咯啉-1-氧化物（DMPO）光谱的电子顺磁共振（EPR）自旋俘获确实证明了MoSe ₂形成了羟基自由基在黑暗中超声振动过程中产生纳米花，这是破坏染料分子的主要活性氧（ROS）。这是第一项工作，以演示使用MoSe ₂纳米花通过压电催化剂作用实现的非常有效的催化剂和氧化还原过程。