Hybrid plasmonic core-shell nanostructures for photocatalysis

Stanford researchers within the Dionne Lab have developed a method to use copper titanium dioxide core-shell nanoparticles for the light driven production of green fuels or removal of contaminants in water.

Current approaches to photocatalysis include semiconductors like titanium dioxide; however, they only absorb ultraviolet light, which forms less than 5% of the sunlight that reaches Earth. A promising approach is the use of hybrid plasmonic metal nanoparticle-semiconductor nanostructures, which are the strongest light absorbers per volume and have a highly tunable absorption cross-section that spans the entire visible and near-IR spectrum. Previous examples of plasmonic-semiconductor hybrids relied on noble metals like gold and silver, which prevented this technology from being scalable for real-world applications.

Stanford researchers instead use core-shell hybrid nanoparticles from earth-abundant copper and titanium precursors. This invention is a simple two step method that can use sunlight to drive photocatalysis. Used for water purification, this invention does not require maintenance, is effective against chemicals, plastics, and pathogens, and results in no toxic byproducts.

Stage of Development

Figure:

Figure description:Copper core absorbs light, and electrons are excited into higher energetic states, leaving behind holes. Electrons and holes are then transferred onto TiO₂. TiO₂ reduces CO2 into solar fuels and industrially useful chemicals (methanol, methane, ethylene). TiO₂ also produces reactive oxygen species (ROS), which can remove contaminants in water.

Image credit: Inventors