CO₂ hydrogenation to produce useful chemicals (such as CO, CH₄, CH₃OH, C₂H₄ and C₂H₆) plays a pivotal role in future energy conversion and storage, in which catalysts lie at the heart. We first performed density functional theory calculations to investigate the mechanism for the CO₂ hydrogenation to CO through the reverse water–gas shift (RWGS) reaction over M₁/W₆S₈ (M = Fe, Ru, and Os) single-atom catalysts (SACs). The results showed that mechanism C (formic acid mechanism) on the Fe₁/W₆S₈ single-atom catalyst is the most suitable pathway for RWGS with 30.1 kcal/mol rate-determining energy barrier. Additionally, on the basis of the energetic span model (ESM) and d-band center position, it is demonstrated that Fe₁/W₆S₈ is effective catalysts for the reaction. Afterward, we chose the most higher catalytic activity catalysts Fe₁/W₆S₈ for CO hydrogenation to CH₄·CH₃OH, C₂H₄ and C₂H₆. CH₄* is formed via CO* → COH* → HCOH* → CH* → CH₂* → CH₃* → CH₄*, the effective barrier for CH₄* formation is 24.8 kcal/mol. CH₃OH* is formed via CO* → COH* → HCOH* → H₂COH* → CH₃OH*, the effective barrier for CH₃OH* formation is 26.0 kcal/mol. On Fe₁/W₆S₈, the CH* species is the most favorable monomeric CHx* species for production of C₂H₄ and C₂H₆, whose formation goes through a path of CO* → COH* → HCOH* → CH*. Once CH* is produced, it will be more selective to C₂H₄ via C–C coupling of CH*, rather than its hydrogenation to CH₄ due to the higher hydrogenation barrier of CH₂ species relative to the barriers for CH* + CH* coupling and subsequent conversion to C₂H₄. Ultimately, C₂H₆ can be produced from further hydrogenation of C₂H₄ with moderate barriers. The present insights are helpful for the design and optimization of highly efficient Fe₁/W₆S₈ SACs used in C₂H₄ and C₂H₆ formation from CO₂ hydrogenation.

CO ₂氢化产生有用的化学物质（例如CO，CH ₄，CH ₃ OH，C ₂ H ₄和C ₂ H ₆）在未来的能量转换和存储中起着关键作用，其中催化剂位于核心位置。我们首先进行密度泛函理论计算，以研究在M ₁ / W ₆ S ₈（M = Fe，Ru和Os）单原子上通过反向水煤气变换（RWGS）反应将CO ₂加氢成CO的机理。催化剂（SAC）。结果表明，Fe ₁ / W ₆ S _8的机理C（甲酸机理）单原子催化剂是具有30.1 kcal / mol速率确定能垒的RWGS最合适的途径。另外，基于高能跨度模型（ESM）和d带中心位置，证明Fe ₁ / W ₆ S ₈是该反应的有效催化剂。之后，我们选择了催化活性最高的催化剂Fe ₁ / W ₆ S ₈进行CO加氢成CH ₄ ·CH ₃ OH，C ₂ H ₄和C ₂ H ₆。CH ₄ *是通过CO *→COH *→HCOH *→CH *→CH ₂ *→CH _3形成的*→CH ₄ *，CH ₄ *形成的有效势垒为24.8 kcal / mol。CH ₃ OH *是通过CO *→COH *→HCOH *→H ₂ COH *→ CH ₃ OH *形成的，形成CH ₃ OH *的有效势垒为26.0 kcal / mol。在Fe ₁ / W ₆ S _8上，CH *是最适合生产C ₂ H ₄和C ₂ H _6的单体CHx * ，其形成过程通过CO *→COH *→HCOH *→ CH *。生成CH *后，它将对C ₂ H ₄更具选择性通过CH *的C–C偶联，而不是将其氢化为CH _4，这是因为CH ₂物种的氢化屏障相对于CH * + CH *偶联和随后转化为C ₂ H _4的屏障更高。最终，C ₂ H ₆可以由具有中等阻挡层的C ₂ H ₄进一步氢化而产生。目前的见解有助于设计和优化用于由CO ₂形成C ₂ H ₄和C ₂ H _6的高效Fe ₁ / W ₆ S ₈ SAC。 氢化。