Non-Colloidal Nanocatalysts Fabricated Using Arc Plasma Deposition and Their Application in Heterogenous Catalysis and Photocatalysis

Abstract

To understand technologically complex catalytic systems and to tailor both activity and selectivity in heterogeneous catalysis and photocatalysis, there is the challenge of bridging the materials gap that exists between two- and three-dimensional model catalytic systems and real catalysts, which are comprised of highly dispersed, oxide-supported metal nanoparticles. While colloid nanoparticles synthesized using wet chemistry have the potential for tuning size, shape, and composition, there are complexities related to the organic capping layers. Therefore, the development of new model catalysts without a capping layer is crucial. Coaxial vacuum arc plasma deposition (APD) is a method to fabricate non-colloidal nanocatalysts that has the potential for large-scale synthesis of nanocatalysts and, at the same time, allows for systematic investigation of intrinsic factors that affect catalytic activity. In this article, we describe the fabrication of catalytic nanoparticles using APD, and their application in heterogeneous catalysis and photocatalysis research. Direct vaporization of metallic materials to deposit active materials on two-dimensional or three-dimensional oxide supports has drawn considerable interest due to its simplicity, high reproducibility, and the possibility for large-scale production. We highlight recent studies on metal-support interactions, the effect of doping on the oxide, and hot electron-driven chemical reactions. In the case of photocatalysis, APD was used to fabricate metal nanoparticles on a hierarchically porous oxide; enhanced hydrogen evolution by doping and porosity was also demonstrated. Therefore, the materials gap in catalysis can be bridged by the potential for large-scale synthesis of a variety of catalysts using APD.