Cao D, Lu G-Q, Wieckowski A, Wasileski S A, Neurock M
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
J Phys Chem B. 2005 Jun 16;109(23):11622-33. doi: 10.1021/jp0501188.
The dual path mechanism for methanol decomposition on well-defined low Miller index platinum single crystal planes, Pt(111), Pt(110), and Pt(100), was studied using a combination of chronoamperometry, fast scan cyclic voltammetry, and theoretical methods. The main focus was on the electrode potential range when the adsorbed intermediate, CO(ad), is stable. At such "CO stability" potentials, the decomposition proceeds through a pure dehydrogenation reaction, and the dual path mechanism is then independent of the electrode-substrate surface structure. However, the threshold potential where the decomposition of methanol proceeds via parallel pathways, forming other than CO(ad) products, depends on the surface structure. This is rationalized theoretically. To gain insights into the controlling surface chemistry, density functional theory calculations for the energy of dehydrogenation were used to approximate the potential-dependent methanol dehydrogenation pathways over aqueous-solvated platinum interfaces.
利用计时电流法、快速扫描循环伏安法和理论方法相结合的方式，研究了在定义明确的低米勒指数铂单晶平面Pt(111)、Pt(110)和Pt(100)上甲醇分解的双路径机制。主要关注点是吸附中间体CO(ad)稳定时的电极电位范围。在这种“CO稳定性”电位下，分解通过纯脱氢反应进行，此时双路径机制与电极 - 底物表面结构无关。然而，甲醇通过平行路径分解形成除CO(ad)产物之外的其他产物时的阈值电位取决于表面结构。这在理论上得到了合理的解释。为了深入了解控制表面化学，利用密度泛函理论对脱氢能量进行计算，以近似水合铂界面上电位依赖的甲醇脱氢路径。
