Promotional Effect of H2 Pretreatment on the CO PROX Performance of Pt1/Co3O4: A First-Principles-Based Microkinetic Analysis

Atomic Pt studded on cobalt oxide is a promising catalyst for CO preferential oxidation (PROX) dependent on its surface treatment. In this work, the CO PROX reaction mechanism on Co3O4 supported single Pt atom is investigated by a comprehensive first-principles based microkinetic analysis. It is found that as synthesized Pt1/Co3O4 interface is poisoned by CO in a wide low temperature window, leading to its low reactivity. The CO poisoning effect can be effectively mitigated by a H2 prereduction treatment, that exposes Co ∼ Co dimer sites for a noncompetitive Langmuir-Hinshelhood mechanism. In addition, surface H atoms assist O2 dissociation via "twisting" mechanism, avoiding the high barriers associated with direct O2 dissociation path. Microkinetic analysis reveals that the promotion of H-assisted pathway on H2 treated sample helps improve the activity and selectivity at low temperatures.