Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany.
Small. 2011 Apr 18;7(8):1086-97. doi: 10.1002/smll.201001931. Epub 2011 Mar 29.
The proton conductivity of benzene-periodic mesoporous silica (PMO) materials functionalized with sulfonic acid groups is investigated using experimental and theoretical techniques. The SO(3) H functionalization of pristine benzene-PMO is realized by three different pathways based on a grafting method in which surface silanol groups and/or benzene rings are used to anchor SO(3) H groups for enhanced proton conductivity. The functionalized material is experimentally characterized using X-ray diffraction, small-angle neutron scattering, and argon adsorption isotherms. After pressing the functionalized benzene-PMOs into pellets, the proton conductivity is deduced from Bode plots of impedance spectra taken in the temperature range of 333-413 K at 100% relative humidity. Using quantum mechanical approaches for selected proton-conduction mechanisms, the free energy barriers for proton transport as well as the local water environment at the surface are calculated. These calculations indicate that different mechanisms from purely bulk water transport are important for the benzene-PMO proton conduction, in agreement with experimental data.
采用实验和理论技术研究了磺酸基团功能化的苯周期性介孔硅（PMO）材料的质子电导率。通过基于接枝法的三种不同途径实现了原始苯-PMO 的 SO3H 功能化，其中表面硅醇基团和/或苯环用于锚定 SO3H 基团以提高质子电导率。使用 X 射线衍射、小角中子散射和氩气吸附等温线对功能化材料进行了实验表征。在将功能化的苯-PMO 压制成颗粒后，从在 100%相对湿度下的 333-413 K 温度范围内的阻抗谱的 Bode 图推导出质子电导率。通过对选定质子传导机制的量子力学方法，计算了质子传输的自由能势垒以及表面处的局部水环境。这些计算表明，与纯体相水传输不同的机制对于苯-PMO 质子传导很重要，这与实验数据一致。
