David Rolf, Tuladhar Aashish, Zhang Le, Arges Christopher, Kumar Revati
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
J Phys Chem B. 2020 Sep 17;124(37):8167-8178. doi: 10.1021/acs.jpcb.0c05282. Epub 2020 Sep 2.
The interfacial region of the graphene oxide (GO)-water system is nonhomogenous due to the presence of two distinct domains: an oxygen-rich surface and a graphene-like region. The experimental vibrational sum-frequency generation (vSFG) spectra are distinctly different for the fully oxidized GO-water interface as compared to the reduced GO-water case. Computational investigations using ab initio molecular dynamics were performed to determine the molecular origins of the different spectroscopic features. The simulations were first validated by comparing the simulated vSFG spectra to those from the experiment, and the contributions to the spectra from different hydrogen bonding environments and interfacial water orientations were determined as a function of the oxidation level of the GO sheet. The ab initio simulations also revealed the reactive nature of the GO-water interface.
富氧表面和类石墨烯区域，氧化石墨烯（GO）-水体系的界面区域是不均匀的。与还原的GO-水体系相比，完全氧化的GO-水界面的实验振动和频产生（vSFG）光谱明显不同。使用从头算分子动力学进行了计算研究，以确定不同光谱特征的分子起源。首先通过将模拟的vSFG光谱与实验光谱进行比较来验证模拟结果，并根据GO片的氧化水平确定不同氢键环境和界面水取向对光谱的贡献。从头算模拟还揭示了GO-水界面的反应性质。
