nanoreactor

Nanoreactor refers to a nanoscale reaction vessel that confines reactants and catalytic sites within a limited volume, thereby influencing reaction pathways, rates, and selectivity. Nanoreactors can be inorganic, organic, or hybrid and take various forms, including core-shell nanoparticles, porous solids, vesicles, or self-assembled assemblies.

Common implementations include core-shell nanoparticles where a catalytic core is encapsulated by a nanometer-scale shell; the shell creates a confined environment that can modify access to active sites and guide product release. Porous materials such as zeolites, mesoporous silica, metal-organic frameworks, and covalent organic frameworks provide fixed nanoscale pores that act as reactors, enabling reactions inside channels with size- and shape-selective effects. Self-assembled systems such as micelles, polymersomes, and dendrimer cages form nanoreactors in solution, while nanoemulsions or microemulsions create aqueous-phase droplets that function as discrete reaction environments. In biology-inspired approaches, liposomes and other vesicles encapsulate enzymes or synthetic catalysts to enable cascade reactions with enhanced stability and controllable diffusion.

Confinement can increase effective concentrations, improve selectivity, enable multi-step catalysis, and simplify product separation. However, challenges include synthesis complexity, limited mass transport, stability of the confined system under reaction conditions, and scalability. Applications include catalysis with improved selectivity and yield; synthesis of nanoparticles with narrow size distributions; multi-step reaction sequences; and drug delivery or biocatalysis. Characterization methods involve transmission electron microscopy, scanning electron microscopy, BET surface area analysis, NMR or infrared spectroscopy, and in situ spectroscopy or diffraction techniques to monitor confinement and reactions.