Polymerized stimuli-responsive microgel hybrids of silver nanoparticles as efficient reusable catalyst for reduction reaction

Biswajit Pany; Amrito Ghosh Majumdar; Suresh Bhat; Satybrata Si; Junpei Yamanaka; Priti S Mohanty

doi:10.1016/j.heliyon.2024.e26244

Polymerized stimuli-responsive microgel hybrids of silver nanoparticles as efficient reusable catalyst for reduction reaction

Heliyon. 2024 Feb 22;10(5):e26244. doi: 10.1016/j.heliyon.2024.e26244. eCollection 2024 Mar 15.

Authors

Biswajit Pany^{1

2}, Amrito Ghosh Majumdar², Suresh Bhat³, Satybrata Si^{1

2}, Junpei Yamanaka⁴, Priti S Mohanty^{1

2}

Affiliations

¹ School of Chemical Technology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar, 751024, India.
² School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar, 751024, India.
³ Polymer Science & Engineering Division, CSIR-National Chemical Laboratory, Pune, 411008, India.
⁴ Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan.

Abstract

We have showcased the potential of polymerized hydrogels (PGMs) with uniform-sized stimuli-responsive microgel particles as promising alternatives to prevent aggregation in solution based nanoparticle systems. In the current work, we implemented the PGM concept by embedding anionic stimuli-responsive microgels (PNIPAM-co-AAc)-silver (Ag) hybrids within a hydrogel matrix. These PGM@AgNP hybrid materials are used as catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride. UV-VIS spectroscopy is used for studying catalytic activity. In the solution based system, the complete reduction of 4-NP to 4-AP took 30 minutes with pure Ag nanoparticles, 24 minutes with PNIPAM-Ag hybrid (Neutral) microgels and 15 minutes with PNIPAM-co-AAc-Ag (Anionic) hybrid microgels. In contrast PGM containing PNIPAM-co-AAc-Ag hybrids achieved full reduction in just 15 minutes, along with a 3-minute induction period. For pure Ag nanoparticles, the first-order rate constant is found to be 0.25 min^-1, for PNIPAM-Ag hybrid (Neutral), it is 0.21 min^-1 and for PNIPAM-co-AAc-Ag (Anionic), it is 0.5 min^-1 where as for PGM containing anionic microgel hybrids it is found to be 0.8 min^-1. Furthermore, the reusability of the PGM-Ag (anionic) materials for catalytic activity remains unaltered even after several washings. In summary, our study highlights the effectiveness of PGM@AgNP materials as efficient catalysts for the reduction of 4-nitrophenol to 4-aminophenol, indicating their versatile potential in various catalytic applications.

Keywords: Light scattering; Microgel-metal hybrids; Nanomaterial catalysts; PNIPAM microgels; Polymerized hydrogel matrix(PGM; Stimuli-responsive microgels.