Hydroxyl anchoring and electron transfer behaviors of atomic single-layer Pt in NH3 oxidation

Abstract

Platinum (Pt) atomic single-layer (ASL) can trigger synergistic effects between metal atoms and surface moieties of supports, which governs its catalytic activity and product selectivity. The electronic metal-support interaction determines not only the local coordination environment in shaping the stability and reactivity of Pt on support, but also the covalency of Pt–O and electron transfer properties. Here, we reveal the impact of different anchoring mechanisms between Pt ASL and supports on catalytic activity and product selectivity of NH₃ oxidation. The Pt ASL consumes more low-coordination terminal hydroxyls on Al₂O₃, and the lower coordination number leads to the stronger electron transfer between Pt ASL and TiO₂. The imino group acts as the key intermediate on Pt/TiO₂ resulting in higher NH₃ conversion but lower N₂ selectivity, whereas the amino group plays a dominant role on Pt/Al₂O₃ leading to slightly lower NH₃ conversion but higher N₂ selectivity because of rapid NH₃∗ dehydrogenation.