Cellulose nanocrystal/clay based macroion nanogel as support for stable platinum catalyst for electrochemical oxidation of methanol in alkaline medium

Abstract

Nanogels are well known for their ability to encapsulate metal nanoparticles. However, only few reports exist on the application of such metal nanoparticle-loaded nanogels as electrocatalyst. Here, the formation of a self-assembled macroion nanogel-based complex using sustainable nanomaterials and its functional application as catalyst support for methanol oxidation in alkaline medium is reported. Physico-chemical and morphological investigations of the nanogel showed the formation of micro-nano particles, suggesting the presence of good ionic interactions. Prepared complex was utilized to host catalytically active platinum nanoparticles. On calcination, Pt-loaded nanogels showed good activity towards methanol oxidation in alkaline medium. Further, based on linear sweep voltammetry, it was proposed that for the current system reported here, reaction intermediates formed in methanol oxidation during the cyclic voltammetry analysis get removed from the catalyst surface during the forward scan, instead of the reverse scan. The proposed hypothesis was further supported by impedance analysis and the potential range for removal of intermediates was determined, which was found to be 0.1 V – 0.2 V in alkaline medium during the forward scan. Thus, it has been successfully demonstrated that such catalytic nanoparticle-encapsulated complexes have good electrochemical activity.