Slow Proton Transfer in Nanoconfined Water
Slow Proton Transfer in Nanoconfined Water
复制标题
DOI：
10.1021/acscentsci.0c00340
复制
发表时间：
2020-06
影响因子：
18.2
通讯作者：
O. Sofronov;H. Bakker
中科院分区：
文献类型：
--
作者：
O. Sofronov;H. Bakker
质子在纳米受限环境中的传输，例如在生物或人造质子传导膜的纳米通道中，对于化学、生物学和纳米技术是必不可少的。在水中，质子扩散通过质子在水分子之间的跳跃而发生。这个过程涉及许多氢键的重排，因此可以受到纳米限制的强烈影响。利用偏振分辨飞秒红外瞬态吸收光谱研究了阳离子表面活性剂稳定的水纳米液滴中水合质子的振动和结构动力学。我们确定的时间尺度的质子跳跃的中心的水纳米液滴从各向异性的瞬态吸收信号的动力学。我们发现，在直径<4 nm的小纳米液滴中，质子跳跃比在本体水中慢10倍以上。即使在相对较大的纳米液滴直径为1.7nm，我们发现，质子跳跃的速度是由1.44倍相比，散装水减慢。
The transport of protons in nanoconfined environments, such as in nanochannels of biological or artificial proton conductive membranes, is essential to chemistry, biology, and nanotechnology. In water, proton diffusion occurs by hopping of protons between water molecules. This process involves the rearrangement of many hydrogen bonds and as such can be strongly affected by nanoconfinement. We study the vibrational and structural dynamics of hydrated protons in water nanodroplets stabilized by a cationic surfactant using polarization-resolved femtosecond infrared transient absorption spectroscopy. We determine the time scale of proton hopping in the center of the water nanodroplets from the dynamics of the anisotropy of the transient absorption signals. We find that in small nanodroplets with a diameter <4 nm, proton hopping is more than 10 times slower than in bulk water. Even in relatively large nanodroplets with a diameter of ∼7 nm, we find that the rate of proton hopping is slowed by ∼4 times compared with bulk water.