Combined Structural and Plasmonic Enhancement of Nanometer-Thin Film Photocatalysis for Solar-Driven Wastewater Treatment

Titanium dioxide(TiO2) thin films are commonly usedas photocatalytic materials. Here, we enhance the photocatalytic activityof devices based on titanium dioxide (TiO2) by combiningnanostructured glass substrates with metallic plasmonic nanostructures.We achieve a three-fold increase of the catalyst's surfacearea through nanoscale, three-dimensional patterning of periodic,conical grids, which creates a broadband optical absorber. The additionof aluminum and gold activates the structures plasmonically and increasesthe optical absorption in the TiO2 films to above 70% inthe visible and NIR spectral range. We demonstrate the resulting enhancementof the photocatalytic activity with organic dye degradation testsunder different light sources. Furthermore, the pharmaceutical drugCarbamazepine, a common water pollutant, is reduced in the aqueoussolution by up to 48% in 360 min. Our approach is scalable and potentiallyenables future solar-driven wastewater treatment.