Group Additivity for Thermochemical Property Estimation of Lignin Monomers on Pt(111)

Conversion of biomass has received considerable attention, but theoretical investigation is challenging due to the large computational burden. In this contribution, we explore group additivity for computing the thermochemistry of lignin monomers, and by extension to single-ring aromatic hydrocarbons, on Pt(111). We find that the previous framework developed for open-chain molecules and furanics is inadequate for lignin monomers due to conjugation. Using quantum theory of atoms in molecules (QTAIM), we find that the type of binding of the adsorbate atoms with the surface sites, for example, σ, σσ, or σπ, has an important impact on the conjugation of bonds in adsorbates. We introduce two new models that account for the type of binding of the central atom and its nearest neighbors, namely, a conjugation-based and a site-based scheme, which result in significant improvement. A total of 591 density functional theory data points were regressed; cross-validation of the site-based scheme reveals that mean absolute errors are 2.81 kcal/mol in ΔHf,298, 1.07 cal/(mol K) in ΔS298, and 0.25 cal/(mol K) in Cp,300. The slightly simpler conjugation-based model, which does not resolve the binding type of all nearest neighbors, also performs well.

生物质转化领域已受到广泛关注，但由于计算量巨大，相关理论研究颇具挑战性。本研究针对Pt(111)晶面，探索了用于计算木质素单体热化学性质的基团加和法，并将其推广至单环芳烃类化合物。我们发现，此前针对开链分子与呋喃类化合物开发的理论框架，因共轭作用的影响，并不适用于木质素单体。借助分子中的原子量子理论（QTAIM），我们发现吸附质原子与表面位点的结合类型（如σ型、σσ型或σπ型），对吸附质内化学键的共轭效应具有显著影响。我们提出了两种新模型，分别纳入中心原子及其最近邻的结合类型：基于共轭的方案与基于位点的方案，二者均实现了性能的显著提升。本研究共回归拟合了591组密度泛函理论计算数据；针对基于位点的方案进行交叉验证结果显示，其298 K标准生成焓（ΔHf,298）、298 K标准熵（ΔS298）以及300 K定压摩尔热容（Cp,300）的平均绝对误差分别为2.81 kcal/mol、1.07 cal/(mol·K)与0.25 cal/(mol·K)。虽未区分全部最近邻的结合类型，但更为简洁的基于共轭的模型同样表现优异。