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

Abstract

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.

Optical and Electrochemical Properties of a Nanostructured ZnO Thin Layer Deposited on a Nanoporous Alumina Structure via Atomic Layer Deposition

“…The practically ideal highly self-ordered nanoporous geometry of NPASs guarantees their potential application in nanofluidics, drug delivery or as nanofilters [ 4 , 5 , 6 ]. Additionally, they exhibit interesting optical characteristics determined by pore size and the growing oxide layer thickness, behaving as photonic crystals and displaying photoluminescence [ 7 , 8 , 9 , 10 ]. Both the geometrical parameters and surface characteristics of the NPASs can be changed through appropriate surface modifications.…”

Stained Glass Effect in Anodic Aluminum Oxide Formed in Selenic Acid

“…Electrochemical oxidation of valve metals in acidic electrolytes, also known as the anodization process, produces porous anodic oxides on the metal surface. Anodic oxides of valve metals have been of great interest to the scientific community owing to their unique structure with aligned pores and intrinsic to the oxides chemical and physical properties. − Numerous advanced materials and devices have been formed using anodic aluminum oxide (AAO) in ongoing research: membranes, − drug delivery systems, nanowires, , photonic crystals, scaffolds for tissue engineering, capacitors, , photocatalysts, and sensors. − …”