Developing an advanced electrocatalyst derived from triangular silver nanoplates@polyvinylpyrrolidone-polyaniline nanocomposites

Abstract

There is a need for developing new and perspective materials for oxygen reduction reaction (ORR) as one of the most essential reactions in the life processes, energy storage, and conversion, in order to exchange the most often used materials based on platinum supported/unsupported substrates, especially carbon supports. Herein, we present low-cost alternative electrode materials consisting of two silver@polyvinylpyrrolidone-polyaniline (Ag@PVP-PANI) nanocomposites that showed great potential as Pt-free ORR electrocatalysts. Simple and effective polymerization processes of aniline in the methanol, using PVP as shape-mediated stabilizator and stimulator of its oxidation by silver ions, led to the formation of nanocomposites with truncated triangular silver nanoparticles dispersed throughout granular and wrinkle-like surfaces of PANI matrix. The behavior of PVP chains in acidic conditions showed great influence on nanocomposites’ conductivities, regardless of the high silver content. Electrocatalytic survey of nanocomposites examined in alkaline media toward ORR pointed out their appreciable activities with high ORR onset potentials. Moreover, for the nanocomposite with lower silver content (18.9 wt. %), the four-electron ORR pathway was evidenced.