Correlating the Reverse Water–Gas Shift Reaction with Surface Chemistry: The Influence of Reactant Gas Exposure to Ni(100)

Using ambient pressure X-ray photoelectron spectroscopy (APXPS) and mass spectrometry (MS) while varying the temperature, we were able to directly understand how sequence of exposing reactant gases, CO2 H2, influenced surface species reverse water–gas shift reaction product formation on Ni(100). When first dosing at room temperature (RT), Ni(100) shows a significant amount oxide due spontaneously dissociating into CO O this is nearly unchanged upon introducing H2. However, when H2 dosed nickel subsequently introduced, spontaneous dissociation still continues yet it forms less pre-adsorbed hydrogen surface. Interestingly, major from both reactions oxide, only small OH observed in either exposure case. This observation confirms that dominant pathway follows redox mechanism. As increases, adsorbed further dissociates atomic carbon oxygen. increase, influence gas no longer exists: desorption as CO(g) takes place cases. It note present even high temperatures over 400 °C, indicating kinetic rate differences between hydrogenation H2O. Our results reveal gases affects reactivity catalyst, providing important insight behavior catalyst surfaces their formation.