Plasmon-enabled degradation of organic micropollutants in water by visible-light illumination of Janus gold nanorods

• Published in: Proceedings of the National Academy of Sciences - PNAS 2020-07, Vol.117 (27), p.15473-15481
• Main Authors: Wei, Haoran, Loeb, Stephanie K., Halas, Naomi J., Kim, Jae-Hong
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Aqueous solutions; Atmospheric chemistry; Charge transfer; Gold; Gold - chemistry; Gold - radiation effects; Gold coatings; Hot electrons; Light; Metal Nanoparticles - chemistry; Metal Nanoparticles - radiation effects; Micropollutants; Nanoparticles; Nanorods; Nanotechnology - methods; Nanotubes - chemistry; Nanotubes - radiation effects; Organic Chemicals - chemistry; Organic Chemicals - toxicity; Oxidation; Oxidation-Reduction - radiation effects; Photochemistry; Photolysis - radiation effects; Physical Sciences; Pollutants; Silica; Silicon dioxide; Silicon Dioxide - chemistry; Silicon Dioxide - radiation effects; Sunlight; Sustainable development; Water - chemistry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Water pollution; Water Pollution, Chemical - prevention & control; Water supply
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2003362117

The development of sustainable methods for the degradation of pollutants in water is an ongoing critical challenge. Anthropogenic organic micropollutants such as pharmaceuticals, present in our water supplies in trace quantities, are currently not remediated by conventional treatment processes. Here, we report an initial demonstration of the oxidative degradation of organic micropollutants using specially designed nanoparticles and visible-wavelength sunlight. Gold “Janus” nanorods (Au JNRs), partially coated with silica to enhance their colloidal stability in aqueous solutions while also maintaining a partially uncoated Au surface to facilitate photocatalysis, were synthesized. Au JNRs were dispersed in an aqueous solution containing peroxydisulfate (PDS), where oxidative degradation of both simulant and actual organic micropollutants was observed. Photothermal heating, light-induced hot electron-driven charge transfer, and direct electron shuttling under dark conditions all contribute to the observed oxidation chemistry. This work not only provides an ideal platform for studying plasmonic photochemistry in aqueous medium but also opens the door for nanoengineered, solar-based methods to remediate recalcitrant micropollutants in water supplies.