Nanoporous Anodic Aluminum Oxide (NAAO) for Catalytic, Biosensing and Template Synthesis Applications (A Review)

Background: Nanoporous anodic aluminium oxide (NAAO) prepared by self-ordering anodization is fascinating and versatile nanostructured material predestined for a variety of applications. Objective: NAAO possesses remarkable properties with a highly ordered array of cylindrical pores which can be produced with tunable pore diameters and inter-pore spacing. For the past few decades, different approaches have been introduced to improve the surface properties of NAAO, however, though the various approached established, surface modification of NAAO is still a significant challenge. In this review, we highlight the current state of research on NAAO addresses the formation, properties and numbers of applications are further demonstrated for the application of catalytic, biosensing and nanostructure templates synthesis. Method: We systematically introduce the concept of material fabrication of the NAAO based on inexpensive electrochemical anodization with the self-ordering process of nanopores and the outcome of the process are entirely ordered and size-controlled nanopores with distinctive pore geometries. Also, we described the recent advances approaches such as chemical vapor deposition (CVD), spin coating, electrodeposition, electroless deposition, impregnation, etc. for structural engineering of the NAAO with targeting applications. Results: The combination of unique properties with tunable pore diameter and surface functionality made these NAAO materials very attractive for a wide range of application such as chemo & biosensors, catalytic and used as a template in the fabrication of various nanostructured materials such as nanorods, nanotubes and nanowires. Conclusion: The present review addresses the formation, properties, surface functionalities and several applications of NAAO.