Enhancing molecular oxygen activation by nitrogen-doped carbon encapsulating FeNi alloys with ultra-low Pt loading.

Modulating the electronic structure of noble metals via electronic metal-support interaction (EMSI) has been proven effectively for facilitating molecular oxygen activation and catalytic oxidation reactions. Nevertheless, the investigation of the fundamental mechanisms underlying activity enhancement has primarily focused on metal oxides as supports, especially in the catalytic degradation of volatile organic compounds. In this study, a novel Pt catalyst supported on nitrogen-doped carbon encapsulating FeNi alloy, featuring ultrafine Pt nanoparticles, was synthesized. This catalyst demonstrated exceptional catalytic activity (92%), recyclability, and water tolerance for the deep oxidation of formaldehyde at room temperature. Structural analyses and theoretical calculations revealed a directional electron transfer from FeNi alloy to Pt, even there is no direct contact between them. This electron penetration effect, mediated by carbon, conferred electron-rich properties to Pt, leading to the activation of molecular oxygen by elongating O-O bond length (1.405 Å). Consequently, efficient formaldehyde removal was achieved with an ultra-low Pt loading. This investigation offers a novel perspective on modulating the electronic structure of Pt by engineering a unique EMSI effect between a nonoxide support and active species, thereby enabling efficient oxygen activation for air purification.