Two‐dimensional photonic metasurfaces for slow light‐controlled photocatalysis

Abstract

Photocatalysis using semiconductor materials like titania (TiO 2 ) is a key method for environmental purification or solar fuel generation. Nanostructures that maximize incident light absorption are highly desired to enhance depollution rate or solar‐to‐fuel conversion efficiency in limited volumes of catalysts. Here, we report on structural and optical properties of metasurfaces based on a 20 nm thick anatase layer conformally deposited onto a wavelength‐scale two‐dimensional periodic photonic lattice. We investigate the NO degradation using such metasurfaces, and evaluate the impact of the patterning on photocatalytic activities between 340 and 400 nm. In the 380–385 nm range, the mean photochemical efficiency is increased by a factor up to 5.7 compared to flat references, with an overall three‐fold enhancement within the whole spectral range of interest. This approach can be applied to numerous types of systems by varying active materials, leading to substantial improvements in air/water depollution, water splitting or artificial photosynthesis processes.