硫酸氢盐存在下铂（111）上氢的电化学还原
The Electrochemical Reduction of Hydrogen in the Presence of Bisulfate on Platinum(111)
摘要：
提出了一个新的析氢反应中间体模型，用于硫酸氢盐存在下铂（111）上氢的电化学还原。这种化合物的形成，一个规则的二维蜂窝状冰晶格，发生一级相变，涉及水分子的重新取向。该模型分析使用新的和简单的有效的聚类方法，突出了系统中的相关过渡。这种方法是基于我们以前在Cu到Au（111）上的UPD研究中成功使用的团簇变分方法，并允许我们探索一个大的参数空间区域，这是研究这个复杂系统的一个基本特征。该理论充分利用了扩散层的性质：水分子随着电势的改变而重新取向。对于正电位，它形成线性链，这是STM观察到的硫酸盐的$\sqrt 3 \times \sqrt 7$结构的原因。在负电位时，水转向，使其偶极子指向Pt。然后它会形成一个由氢键分子组成的规则的蜂窝状网络，硫酸盐位于六边形的中心。然后硫酸氢盐被解吸，留下蜂窝状HER结构。因此，我们的模型提供了一个众所周知的事实，即只有2/3的铂原子参与电解还原的氢的解释。该理论隐含了对水势的几何约束。
英文摘要：
A new model for the intermediate compound of the hydrogen evolution reaction (HER) is proposed, for the electrochemical reduction of hydrogen in the presence of bisulfate on platinum(111). The formation of this compound, a regular 2 dimensional honeycomb ice lattice, occurs by a first order phase transitions that involves the reorientation of water molecules. The model is analyzed using new and simple effective cluster approach which highlights the relevant transitions in system. This method is based on the cluster variation method used successfully in our previous work on the UPD of Cu onto Au(111), and permits us to explore a large region of parameter space, an essential feature to study this complex system. The theory makes full use of the properties of the diffuse layer: The water molecule is reoriented as the potential is changed. For positive potentials it forms linear chains which are responsible for the $\sqrt 3 \times \sqrt 7$ structure of the sulfate observed by STM. At negative potentials water turns so that its dipole points towards the Pt. Then it will form a regular honeycomb network of hydrogen bonded molecules, with the sulfate at the center of the hexagons. Then the bisulfate is desorbed, leaving the honeycomb HER structure behind. Our model thus provides an explanation of the well known fact that only 2/3 of the Pt atoms participate in the electroreduction of the hydrogen. The theory implies geometrical constraints to the water potential.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
