Mechanistic Insights into Solution-Phase Oxidative Esterification of Primary Alcohols on Pd(111) from First-Principles Microkinetic Modeling

We
present an ab initio microkinetic model for the oxidative esterification
of 1-propanol to methyl propionate over Pd(111). The model fully accounts
for solvation of solution-phase species and added catalytic base and
provides key insights into the factors that limit the activity of
unpromoted Pd aerobic oxidation catalysts. In particular, we find
that the activity is limited by the large steady-state surface H coverage,
which destabilizes other adsorbed intermediates via lateral interactions,
and substantial barriers governing the formation of O–H bonds,
which is required for the reduction of O2 and removal of
H byproducts from the catalyst surface.

本工作报道了Pd(111)晶面上1-丙醇氧化酯化制备丙酸甲酯的从头算（ab initio）微动力学模型。该模型全面考虑了溶液相物种与外加催化碱的溶剂化效应，为揭示未促进钯基好氧氧化催化剂的活性限制机制提供了关键洞见。具体而言，研究发现催化剂活性受限于较高的稳态表面氢覆盖度：该覆盖度通过横向相互作用破坏了其他吸附中间体的稳定性；同时，调控O-H键形成的显著能垒同样构成活性限制因素——这一过程是氧气还原与催化剂表面氢副产物脱除的必要步骤。