Converting carbon dioxide (CO2) into liquid fuels and synthesis gas is a world-wide priority. But there is no experimental information on the initial atomic level events for CO2 electroreduction on the metal catalysts to provide the basis for developing improved catalysts. Here we combine ambient pressure X-ray photoelectron spectroscopy with quantum mechanics to examine the processes as Ag is exposed to CO2 both alone and in the presence of H2O at 298 K. We find that CO2 reacts with surface O on Ag to form a chemisorbed species (O = CO2δ−). Adding H2O and CO2 then leads to up to four water attaching on O = CO2δ− and two water attaching on chemisorbed (b-)CO2. On Ag we find a much more favorable mechanism involving the O = CO2δ− compared to that involving b-CO2 on Cu. Each metal surface modifies the gas-catalyst interactions, providing a basis for tuning CO2 adsorption behavior to facilitate selective product formations.
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机译：将二氧化碳（CO2）转化为液体燃料和合成气是世界范围内的首要任务。但是，没有关于在金属催化剂上进行CO 2电还原的初始原子能级事件的实验信息，可为开发改进的催化剂提供基础。在这里，我们将环境压力X射线光电子能谱与量子力学结合起来，研究了Ag单独暴露于CO2以及在298 K的H2O存在下暴露于CO2的过程。我们发现CO2与Ag上的表面O反应形成化学吸附物种（O = CO2 δ-）。然后加入H2O和CO2导致最多有四个水附着在O = CO2 δ-上，两个水附着在化学吸附的（b-）CO2上。在Ag上，我们发现与Ob = CO2 δ-相比，在Cu上涉及b-CO2的机制更为有利。每个金属表面都会改变气体-催化剂的相互作用，从而为调整CO2的吸附行为提供了基础，以促进选择性的产物形成。
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