Exploration of catalyst structure and environmental sensitivity for C–O bond scission is essential for improving the conversion efficiency because of the inertness of CO₂. We performed density functional theory calculations to understand the influence of the properties of adsorbed water and the reciprocal action with oxygen vacancy on the CO₂ dissociation mechanism on Zn₂GeO₄(010). When a perfect surface was hydrated, the introduction of H₂O was predicted to promote the scission step by two modes based on its appearance, with the greatest enhancement from dissociative adsorbed H₂O. The dissociative H₂O lowers the barrier and reaction energy of CO₂ dissociation through hydrogen bonding to preactivate the C–O bond and assisted scission via a COOH intermediate. The perfect surface with bidentate-binding H₂O was energetically more favorable for CO₂ dissociation than the surface with monodentate-binding H₂O. Direct dissociation was energetically favored by the former, whereas monodentate H₂O facilitated the H-assisted pathway. The defective surface exhibited a higher reactivity for CO₂ decomposition than the perfect surface because the generation of oxygen vacancies could disperse the product location. When the defective surface was hydrated, the reciprocal action for vacancy and surface H₂O on CO₂ dissociation was related to the vacancy type. The presence of H₂O substantially decreased the reaction energy for the direct dissociation of CO₂ on O_2c1- and O_3c2-defect surfaces, which converts the endoergic reaction to an exoergic reaction. However, the increased decomposition barrier made the step kinetically unfavorable and reduced the reaction rate. When H₂O was present on the O_2c2-defect surface, both the barrier and reaction energy for direct dissociation were invariable. This result indicated that the introduction of H₂O had little effect on the kinetics and thermodynamics. Moreover, the H-assisted pathway was suppressed on all hydrated defect surfaces. These results provide a theoretical perspective for the design of highly efficient catalysts.

中文翻译：

---

Zn ₂ GeO ₄（010）上CO ₂还原过程中水和氧缺陷在C–O断裂中的关键作用

由于CO ₂的惰性，探索C–O键断裂的催化剂结构和环境敏感性对于提高转化效率至关重要。我们进行了密度泛函理论计算，以了解吸附水的性质以及氧空位的相互作用对Zn ₂ GeO ₄（010）的CO ₂离解机理的影响。当完美的表面被水合时，根据其外观，H ₂ O的引入可通过两种模式促进分裂过程，最大程度地促进了离解性吸附H ₂ O的分解。离解性H ₂ O降低了势垒和反应能的CO₂通过氢键解离以预激活C–O键，并通过COOH中间体辅助断裂。具有二齿结合的H ₂ O的理想表面比具有单齿结合的H ₂ O的表面在能量上更有利于CO ₂分解。前者在能量上有利于直接离解，而单齿H ₂ O促进了H辅助途径。有缺陷的表面对CO _2的分解具有比完美表面更高的反应性，因为氧空位的产生会分散产物的位置。当缺陷表面被水化时，空位和表面H ₂ O对CO ₂的相互作用解离与空缺类型有关。H的存在₂ ö基本上降低了反应能量为CO的直接离解₂ O对_2C1 -和O _3C2 -defect表面，其转换为放热反应的吸热反应。但是，增加的分解势垒使该步骤在动力学上不利，并降低了反应速率。当O _2c2缺陷表面上存在H ₂ O时，直接离解的势垒和反应能均不变。该结果表明H ₂的引入O对动力学和热力学影响很小。此外，在所有水合缺陷表面上均抑制了H辅助途径。这些结果为高效催化剂的设计提供了理论依据。