Metallogel templated nanoparticle fabrication and nanocatalysis

The recent upsurge of integrating self-assembled stimuli-responsive gels with catalytic metal nanoparticles (MNPs) has provided a great opportunity to overcome the individual limitations of both the materials in order to generate efficient nanocatalytic hybrid materials. An alluring approach for the production of these nanocatalytic composites is in situ formation of well arranged MNPs using metallogels as synthetic templates due to the ordered 3-dimensional arrangement of metal ions inside their fibrillar matrices. The flexibility of the gel network, porosity, pre-existing reducing functionalities in gelator molecules, well-defined arrangement of metal ions in gel nanofibers at regular intervals, and dynamic nature of the entrapped solvent synchronously aid in the formation of stable MNPs by in situ reduction of metal ions, as well as preventing agglomeration and leaching by acting as NP capping matrices. This critical review firstly aims to provide an insight into some of the recent advancements in the synthesis of these comparatively less explored metallogel-MNP composites with an insight into the choice of gelators and a deeper understanding of how the metallogels can act as a superior template for the preparation and stabilisation of MNPs. Later on, we provide a thorough discussion of their catalytic application towards various chemical and electrochemical transformations.