Reaction mechanism and catalytic activities of methanol (CH₃OH) and CO formations from CO₂ hydrogenation at all the different surface oxygen vacancy (O_v) sites on the stable cubic In₂O₃ (c-In₂O₃) (111) flat surface and (110) flat and (110) step surfaces were thoroughly investigated in order to establish the structure-performance relationship using density functional theory calculations. For CH₃OH formation, the R2 step for bidentate formate intermediate (bi-HCOO*) hydrogenation to the dioxymethylene intermediate (H₂COO*), or the R3 step for H₂COO* dissociation to the formaldehyde intermediate (CH₂O*) and surface O atom, was calculated to be the rate-determining step (RDS), whereas for CO formation, the R1a step for bent CO₂ adsorbate (bt-CO₂*) protonation to the carboxylate intermediate (COOH*), was calculated to be the only RDS. Further data science analysis using the perceptron learning and decision tree algorithms shows that the RDS for CH₃OH formation for a given O_v site can be determined by the stability of two key reaction intermediates (H₂COO* and CH₂O*) along with the formation energy of the O_v site. Linear regression analysis was also performed to establish linear relationships between the activation barriers and corresponding reaction energies for R2 and R3 steps, which can also be useful in determining the actual RDS for CH₃OH formation. Although the adsorption energies of the linear CO₂ configuration intermediate (ln-CO₂*) and the bt-CO₂* as well as the difference between the activation barriers of the RDS for CO and CH₃OH formations are required for reliably predicting the catalytic activity and product selectivity, our studies suggest a simple and intuitive structure-performance relationship for the c-In₂O₃ catalyst that tri-coordinated O_v sites favor CH₃OH formation, whereas bi-coordinated O_v sites favor CO formation.

在稳定的立方In ₂ O ₃（c -In ₂ O ₃）（111）上所有不同表面氧空位（O _v）处，甲醇（CH ₃ OH）和CO ₂加氢生成的CO的反应机理和催化活性为了使用密度泛函理论计算建立结构与性能的关系，对平坦表面和（110）平坦表面和（110）台阶表面进行了彻底研究。对于CH ₃ OH的形成，R2步骤用于将甲酸酯中间体（bi-HCOO *）氢化成二甲醛中间体（H ₂ COO *），或R3步骤用于H ₂分解为甲醛中间体（CH ₂ O *）和表面O原子的COO *被计算为速率确定步骤（RDS），而对于形成CO而言，弯曲的CO ₂被吸附物（bt-CO ₂ * ）质子化为羧酸盐中间体（COOH *），据计算是唯一的RDS。使用感知器学习和决策树算法进行的进一步数据科学分析表明，对于给定的O _v位点，CH ₃ OH形成的RDS可以通过两个关键反应中间体（H ₂ COO *和CH ₂ O *）的稳定性来确定。与O _v的形成能地点。还进行了线性回归分析以建立活化势垒与R2和R3步骤的相应反应能之间的线性关系，这对于确定CH ₃ OH形成的实际RDS也可能有用。尽管需要线性CO ₂构型中间体（ln-CO ₂ *）和bt-CO ₂ *的吸附能，以及RDS对CO和CH ₃ OH形成的活化能垒之间的差异，才能可靠地预测催化活性和产物选择性，我们的研究表明c -In ₂ O ₃具有简单直观的结构-性能关系三配位的O _v位有利于CH ₃ OH的形成，而双配位的O _v位有利于CO的形成的催化剂。