Using ambient pressure XPS (APXPS), we explored carbon dioxide (CO₂) adsorption and CO₂ hydrogenation on Pt(1 1 1) single crystal surface to observe the activation of CO₂ and the subsequent reaction mechanism. In pure CO₂, we observed CO adsorbates and adsorbed oxygen on Pt(1 1 1) derived from CO₂ dissociation at room temperature. The introduction of H₂ (at a pressure ratio of 1:1 (H₂:CO₂)) increased the production of CO across all temperatures by facilitating the removal of surface oxygen. As a consequence, the surface could expose sites that could then be utilized for producing CO. Under these conditions, the reverse water–gas shift (RWGS) reaction was observed starting at 300 ^oC. At higher H₂ partial pressure (10:1 (H₂:CO₂)), the RWGS reaction initiated at a lower temperature of 200 ^oC and continued to enhance the conversion of CO₂ with increasing temperatures. Our results revealed that CO₂ was activated on a clean Pt(1 1 1) surface through the dissociation mechanism to form adsorbed CO and O at room temperature and at elevated temperatures. Introducing H₂ facilitated the RWGS as adsorbed oxygen was consumed continuously to form H₂O, and adsorbed CO desorbed from the surface at elevated temperatures. This work clearly provides direct experimental evidence for the surface chemistry of CO₂ dissociation and demonstrates how hydrogen impacts the RWGS reaction on a platinum surface.

使用环境压力XPS（APXPS），我们探索了Pt（1 1 1）单晶表面上的二氧化碳（CO ₂）吸附和CO ₂加氢，以观察CO ₂的活化及其后续反应机理。在纯CO _2中，我们观察到CO在室温下源自CO ₂分解的Pt（1 1 1）上吸附并吸附了氧气。引入H ₂（压力比为1：1（H ₂：CO ₂））通过促进表面氧的去除增加了在所有温度下CO的产生。结果，表面可能暴露出可用于产生CO的位置。在这些条件下，观察到从300 ^o C开始的水煤气逆反应（RWGS）。在更高的H ₂分压（10：1 （H ₂：CO ₂）），在200更低的温度下开始的RWGS反应^Ò C和继续加强CO的转化₂随温度。我们的结果表明，CO ₂通过离解机理在干净的Pt（1 1 1）表面上活化了三氧化二砷，在室温和升高的温度下形成吸附的一氧化碳和氧。引入H ₂促进了RWGS，因为吸收的氧气不断消耗形成H ₂ O，并且在高温下从表面脱附的吸收的CO。这项工作清楚地为CO ₂解离的表面化学提供了直接的实验证据，并证明了氢如何影响铂表面上的RWGS反应。