‘Dip Catalysts’ Based on Polymer‐Metal Nanocomposite Thin Films: Combining Soft‐Chemical Fabrication with Efficient Application and Monitoring

Abstract

Nanocatalysts can potentially harmonize the advantages of homogeneous and heterogeneous catalysts, provided they are sequestered in a suitable host matrix that not only enables convenient introduction into repeated reaction cycles, but also allows facile access for the reaction system. Polymer-metal/semiconductor nanocomposite thin films fabricated through an in situ protocol offer a promising solution involving eco-friendly synthesis and sustainable application. Salient features of the approach include (i) the simple, softchemical fabrication methodology that also allows real-time observation of the catalyst formation, (ii) efficient nano-catalyst action through the facile movement of the reactants and products to and from the catalyst site enabled by the swelling of the polymer matrix, and (iii) realization of the 'dip catalyst' concept that emphasizes the ease of insertion and retrieval of the thin film into and from the reaction system, coupled with the feasibility of effective catalyst monitoring through multiple uses. An overview of the nanocomposite thin film fabrication, types of nanostructures that have been reported in this context, deployment of the thin film 'dip catalysts' in several reactions, and emerging new directions in the field and open problems are presented.[a] U.

Spray-Assisted Interfacial Polymerization to Form CuII/I@CMC-PANI Film: An Efficient Dip Catalyst for A3 Reaction

“…In 2010, a pioneering researcher Radhakrishnan developed the concept of “dip catalyst”, and successively presented an Ag nanoparticle-embedded PVA thin film for the reduction of 4-nitrophenol by sodium borohydride [ 1 ]. Since then, the dip catalyst, which can switch the reaction on and off instantaneously, by merely dipping in and out of the reaction vessels, has drawn increasing attention for its ease of fabrication, excellent catalytic performance, convenient separation and reusability, and environmental friendliness [ 2 ]. To date, the dip catalyst has emerged as one of the most powerful tools in catalysis, synthetic methodology, materials science, and environmental science.…”

Copper on chitosan-modified cellulose filter paper as an efficient dip catalyst for ATRP of MMA

“…"Dip catalyst" is a nanocomposite thin film based on proper structural materials and noble metal nanoparticles 15 . Recently, dip catalyst by unique properties such as green and easy usage, excellent recovery, simple fabrication, and activation/deactivation reactions through insertion/deletion, has attracted much attention among other catalysts 11 , 16 .…”

“…Dip catalyst, paper-based composite, afforded through dip-coating of FPs 17 , 18 . Dip catalysts as a new generation of catalysts in ATRP reactions with having extensive recyclability, not only cause to decrease toxicity and post-polymerization purification costs but also allow a controlled polymerization through the polymerization start/stop instantaneously by insertion/removal 15 .…”

Metal-Immobilized Micellar Aggregates of a Block Copolymer from a Mixed Solvent for a SERS-Active Sensing Substrate and Versatile Dip Catalysis

“…Metals such as Ag and Pd nanoparticles are efficient catalysts for a number of chemical reactions, but their reuse and easy separation from the reaction mixture are real challenges. It has been reported that polymer thin films where metal nanoparticles are embedded could be an alternative class of efficient, reusable, and easily fabricated catalysts. ,, As discussed earlier, an amphiphilic block copolymer layer containing different micelle structures could be used as a template to fabricate nanostructured surfaces of metal and can be used for reusable, easily separable, and cost-effective catalysts. There are several reports of metal nanoparticle synthesis using block copolymer micelles as templates for catalysis, but in most of cases, the catalyst is in the solution phase. − …”