Enhancing the Photocatalytic Activity by Tailoring an Anodic Aluminum Oxide Photonic Crystal to the Semiconductor Catalyst: At the Example of Iron Oxide

• Published in: Advanced materials interfaces 2023-12, Vol.10 (36), p.n/a
• Main Authors: Hedrich, Carina, Burson, Anna R., González‐García, Silvia, Vega, Víctor, Prida, Victor M., Santos, Abel, Blick, Robert H., Zierold, Robert
• Format: Article
• Language: English
• Subjects: Absorption; Aluminum; Aluminum oxide; anodic aluminum oxide; atomic layer deposition; Catalytic activity; Current carriers; Degradation; Energy gap; Iron oxides; Photocatalysis; Photocatalysts; Photonic crystals; slow photon effect
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202300615

Photonic crystals (PhCs) are interesting structures for photocatalytic applications because of their capability of harnessing distinct forms of light–matter interactions within the PhCs. Of all these, overlapping one of the photonic stopband's (PSB) edge with the absorption of the PhC material or adsorbed molecules improves their excitation and generated charge carriers can subsequently induce photocatalytic reactions. The PSB position of anodic aluminum oxide PhCs (AAO‐PhCs) can be easily adjusted by modifying the anodization profile. Herein, AAO‐PhCs are designed to match the band gap of a model semiconductor enabling a general photocatalytic activity enhancement independent of the chemical to be decomposed. Fe2O3, as an example photocatalyst, is coated onto AAO‐PhCs to demonstrate efficient photocatalytic systems by utilizing the slow photon effect. Tailored Fe2O3‐AAO‐PhCs with their PSB edge at 564 nm matching the Fe2O3 band gap exhibit generally enhanced degradation of three different organic dyes while a significant activity decrease is observed when the PSB edge does not overlap with the Fe2O3 absorption. Furthermore, photocatalyst degradation can be reduced down to only 4% activity loss over six consecutive measurements by an ultra‐thin alumina coating. Anodic aluminum oxide photonic crystals (AAO‐PhCs) are tailored to enhance photocatalytic degradation reactions by the slow photon effect. The AAO‐PhCs are structurally engineered to align the photonic stopband edge with the band gap of iron oxide as an example semiconductor to allow for a general increase of photocatalytic activity regardless of the chemical being degraded.