(222d) Plasmonic Purification: Visible-Light-Driven Generation of Reactive Oxygen Species for Water Disinfection

Willis, D., Louisiana State University
McPeak, K. M., Louisiana State University
Taylor, K., Louisiana State University
Stofela, S. K. F., Louisiana State University
Increasing access to clean drinking water is a global sustainability goal1. Solar energy can disinfect water through the generation of reactive oxygen species (ROS), but current methods utilize ultraviolet (UV) light, which makes up only 5% of the solar spectrum. Visible-light-driven ROS generation is a promising alternative but stable, highly absorbing materials with the proper oxidation and reduction potentials are necessary.

Here we report on the fabrication and characterization of a plasmonic photocatalyst for visible-light-driven ROS generation. Our plasmonic photocatalyst is a broadband absorber capturing 90 % of the solar spectrum centered around 600 nm. We test its ability to generate ROS in a custom-built continuous flow microreactor allowing rapid real-time measurements of H2O2 generation. Under UV filtered AM1.5G illumination our photo-microreactor generates ~5 μM H2O2 per minute. We will discuss the performance and stability of our plasmonic photocatalyst and propose a reaction pathway for visible-light-driven ROS generation. The effects of photocatalyst geometry, residence time in the photo-microreactor and excitation spectrum will also be discussed.

1) World Health Organization. 2012. Progress on Drinking Water and Sanitation. Geneva, Switzerland: WHO Press.