Ligand‐Free Yolk‐Shell Nanoparticles: Synthesis and Catalytic Applications

Ligand‐Free yolk‐shell nanoparticles (LFYSNs) consist of ligand‐free core (nanoparticle) enclosed in a hollow nanocavity of a porous shell have been attracted great interest owing to their unique nanoarchitecture features, enchanting physicochemical properties and extensive potential applications. LFYSNs are considered as a unique category of conventional yolk‐shell nanoparticles (YSNs). YSNs are usually consist of organic‐capped core (nanoparticle) and the presence of capping ligands on the surface of metal core may show deleterious effects in catalytic applications. Here, a comprehensive overview on the recent progress of LFYSNs synthetic strategies and catalytic applications are discussed. The fabrication methods for LFYSNs are mainly focused on a ‘‘ship‐in‐a‐bottle/pre‐shell’’ approach and sub‐divided into three categories, including volume confined, photochemical and seedless/colloidal methods. The catalytic applications of LFYSNs including chemical and photo catalysis, and electrocatalysis are discussed in detail. Moreover, the superlative catalytic activity of LFYSNs is highlighted. Finally, perspectives on future research direction and development of LFYSNs are discussed briefly.