Using ab initio calculations we investigate the mechanism of ethanol dehydrogenation on Pt catalyst. The calculated adsorption energies indicate ${\mathrm{CH}}_4$ and ${\mathrm{H}}_2$ as final products, which is consistent with experimental observations. A detailed analysis of reaction pathways with measured and computed data indicates partial desorption of ${\mathrm{CH}}_3\mathrm{CHO}$ and $\mathrm{CO}$, with both processes occurring simultaneously and rapidly. We found that the latter is not preceded by the formation of surface CO species and results from: (1) a kinetic process due to the high activation barrier for C–C bond breaking during the ethanol degradation process and (2) an initial CO configuration that favors its desorption. Besides deciphering the new mechanism, our calculations validate previously suggested degradation pathways and show that the combination of experiment and simulations is an effective approach to improve our understanding of catalytic reactions.

通过从头计算，我们研究了Pt 催化剂上乙醇脱氢的机理。计算的吸附能表明${\mathrm{CH}}_4$和${\mathrm{H}}_2$作为最终产品，这与实验观察结果一致。通过测量和计算数据对反应途径进行详细分析表明部分解吸${\mathrm{CH}}_3\mathrm{CHO}$和$\mathrm{一氧化碳}$，两个过程同时快速发生。我们发现，后者并不先于表面CO物种的形成，其结果是：（1）由于乙醇降解过程中C-C键断裂的高活化能垒而导致的动力学过程和（2）初始CO构型这有利于其解吸。除了破译新机制之外，我们的计算还验证了之前提出的降解途径，并表明实验和模拟的结合是提高我们对催化反应理解的有效方法。