Ionic Precursors Transformed Into Vinyl Acetate Synthesis Catalyst via Reaction‐Driven Restructuring

ABSTRACT Conventional preparation of supported bimetallic catalysts relies on solution‐mediated metal salt immobilization and pre‐formation of alloy nanoparticles before reaction. Here, we report a fundamentally different synthesis strategy of using a physical mixture of salt precursors to generate an active catalyst during reaction. The catalytic structure is generated in situ from Pd 3 (OAc) 6 , Au(OH) 3 , and KOAc through H 2 treatment and reaction‐driven restructuring under vinyl acetate monomer (VAM) synthesis conditions. Ascertained from in situ X‐ray diffraction and operando infrared spectroscopy analyses, reduction treatment produces segregated Pd and Au domains, and subsequent exposure to a VAM reaction mixture triggers dynamic extraction of Pd from the metal surface. This latter process, mediated by acetate‐assisted redox cycles, facilitates Pd migration toward Au domains to form a near‐surface localized Pd 50 Au 50 alloy phase. Monometallic Pd domains serve as a reservoir of Pd to the alloy phase, leading to and sustaining a more Pd‐enriched active surface and a higher population of accessible Pd sites, compared to a conventionally prepared K‐PdAu/SiO 2 catalyst. Consequently, this leads to a twofold increase in the VAM formation rate, demonstrating highly active bimetallic catalysts can be generated through the gas‐phase treatment of physically mixed ionic precursors.