Promotional Effect of H 2 Pretreatment on the CO PROX Performance of Pt 1 /Co 3 O 4 : 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 Co 3 O 4 supported single Pt atom is investigated by a comprehensive first-principles based microkinetic analysis. It is found that as synthesized Pt 1 /Co 3 O 4 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 H 2 prereduction treatment, that exposes Co ∼ Co dimer sites for a noncompetitive Langmuir-Hinshelhood mechanism. In addition, surface H atoms assist O 2 dissociation via "twisting" mechanism, avoiding the high barriers associated with direct O 2 dissociation path. Microkinetic analysis reveals that the promotion of H-assisted pathway on H 2 treated sample helps improve the activity and selectivity at low temperatures.