Here, we study the adsorption of methanol vapor under ambient pressure and temperature conditions on low-index Cu surfaces using surface-sensitive infrared (IR) and X-ray spectroscopy techniques. The first step of methanol decomposition, i.e., breaking of the O–H bond to form surface-bound methoxy, readily occurs under ambient conditions. Time-lapse IR spectra clearly indicate a gradually decreasing methoxy coverage, which does not obey well-established kinetic models. We rationalize the initial temperature-independent, high, nonequilibrium coverage of methoxy by a H-bonded methanol assembly in the precursor state. A temperature-dependent equilibrium coverage is achieved as the excess methoxy is eliminated gradually via further dehydrogenation to CO that desorbs to the gas phase. The kinetics of this process displays a significant structure sensitivity with considerably faster kinetics on the Cu(110) surface compared to Cu(111) and Cu(100) surfaces.

中文翻译：

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环境条件下铜表面的甲醇分解：机理、表面动力学和结构敏感性

在这里，我们使用表面敏感红外 (IR) 和 X 射线光谱技术研究了在环境压力和温度条件下甲醇蒸汽在低指数 Cu 表面上的吸附。甲醇分解的第一步，即，在环境条件下很容易发生 O-H 键断裂以形成表面结合的甲氧基。延时红外光谱清楚地表明甲氧基覆盖率逐渐降低，这不符合完善的动力学模型。我们通过在前体状态下的氢键甲醇组装使甲氧基的初始温度独立、高、非平衡覆盖合理化。随着过量甲氧基通过进一步脱氢生成 CO 并解吸到气相中而逐渐消除，从而实现了与温度相关的平衡覆盖。与 Cu(111) 和 Cu(100) 表面相比，该过程的动力学显示出显着的结构敏感性，Cu(110) 表面的动力学明显更快。