Aerosol Spray Drying Guided Synthesis of Ultrasmall Alloyed Bimetallic Nanoparticles Supported on Silica for Catalytic Semihydrogenation. Issue 7 (9th December 2022) - Wang, Hao
Abstract: Supported bimetallic nanoparticles (NPs) with ultrasmall sizes and homogeneous alloying are attractive for catalysis. However, facile synthesis of this type of material remains very challenging. Here, the aerosol drying impregnation method for rapid, scalable, and general synthesis of silica‐supported bimetallic NPs is proposed. The method relies on aerosol spray drying to promote the mixing and dispersing of binary metal precursors on SiO2 . It is capable of controlling the composition and size of bimetallic NPs and avoids the use of expensive metal complex salts and complicated experiment procedures. Twelve permutations combining a noble metal (Pd, Ru, and Pt) and a base one (Fe, Co, Ni, and Cu) with ultrasmall sizes (1.4–2.2 nm in average size), uniform dispersion, and good alloying are synthesized. Interesting activity and selectivity trends in catalytic semihydrogenation of phenylacetylene over the supported Pd‐based NPs can be observed. The silica‐supported PdNi NPs deliver both high activity and styrene selectivity. Spectroscopic and density functional theory calculation results reveal the improved chemoselectivity originated from the suitably down‐shifted d‐band center of the PdNi NPs inducing an increased energy barrier for overhydrogenation and a weakened styrene adsorption. Abstract : Synthesis of ultrasmall bimetallic nanoparticles (NPs) using easily available precursors and industrial compatible processes is challenging. This work proposes the aerosol drying impregnation method for general synthesis of silica‐supported ultrasmall bimetallic NPs. The PdNi NPs show high activity and styrene selectivity in semihydrogenation of phenylacetylene because of the increased barrier for overhydrogenation and decreased barrier for styrene desorption.