Photocatalysts, which convert solar energy directly into chemical energy have played a pivotal role in various solar energy applications such as hydrogen production (water splitting), water or air purification, carbon dioxide removal, nitrogen fixation, and sterilization. However, the target efficiency of photocatalysts is yet to be achieved (solar-to-hydrogen conversion efficiency value of 10%), as required for practical applications. This is mainly due to limited charge separation and transfer kinetics, and many attempts have been made to overcome this problem. One potential solution is piezoelectricity-promoted photocatalysts, or photo-piezo catalysts, which potentially offer improved efficiency realized through the synergistic effects of the coupling between piezoelectric polarization and photoexcitation. Photo-piezo catalysts are particularly suitable for outdoor applications, where there is sunlight and mechanical motions such as waves, winds, and life vibrations.
LLNL researchers have introduced the use of a kirigami inspired substrate to act as a mechanical transducer, which converts macroscale stretching motion into localized bending. The performance of photo-piezocatalysts made with aligned arrays of photocatalytic nanomaterials on the kirigami shaped substrate yields significant enhancements (~250%) in the degradation of dyes.
Image Caption: Kirigami photo-piezo catalyst for degradation of antibiotics and organic pollutants
Won Jin Choi, Changhee Cho, Deuk-Kyu Hwang, and Tae Il Lee, ACS Nano 2023, 17, 16, 16221–16229 (https://doi.org/10.1021/acsnano.3c05787)
Current stage of technology development: TRL 2
LLNL has filed for patent protection on this invention.
- Kirigami substrate structure leads to a potentially significant enhancement up to 2.5x in photocatalytic efficiency.
- Kirigami substrate compatible with existing photocatalytic materials.
- Kirigami-substrate enhanced photo-piezo catalysts demonstrate feasibility in nature for self-sustainable environmental remediation which can be activated using motions of winds, waves, and life vibrations.
- Outdoor water and air purification
- Indoor AC ventilation purifier
