Photocatalytic Pt/Ag3VO4 micromotors with inherent sensing capabilities for corroding environments

Abstract

Autonomous self-propelled micromachines based on semiconductors are at the forefront of environmen-tal pollutants degradation research to palliate the effects of the contamination arising from the constant manufacturing of new products. Nonetheless, testing these micromotors with real-life products is almost an unexplored field, limiting the degradation of pollutants to single-component aqueous solutions or sus-pensions at the laboratory scale, which hinders the translation of these micromachines into useful sys-tems. Herein, Ag3VO4 has been devised as a micromotor by an asymmetric deposition of a thin layer of Pt, giving rise to Pt/Ag3VO4 micromotors (Janus particle). Their motion capabilities have been demon-strated under UV light in fuel-free conditions. Their photocatalytic performance at laboratory scale has been confirmed for the degradation of Rhodamine B while, as a first approximation of a real-life applica-tion, the degradation of an energy drink has also been tested. During this latter exploration, the Pt/Ag3VO4 micromotors were corroded by the citric acid present in the pollutant, releasing Ag nanoparticles into the media. As a proof of concept, the position of the generated Ag nanoparticles' surface plasmon resonance absorption maximum has been demonstrated to show a dependency on the concentration of citric acid.