2D and 3D Silica‐Template‐Derived MnO₂ Electrocatalysts towards Enhanced Oxygen Evolution and Oxygen Reduction Activity

Abstract

Abstract In this work, a hard‐template‐based nano‐replication process is employed to prepare mesoporous MnO 2 materials. We adopted four silica materials, namely, SBA‐15, KIT‐6, MCM‐41, and MCM‐48 as templates to prepare MnO 2 materials by using a nanocasting route. The structural characteristics of the resultant MnO 2 materials were thoroughly investigated by using XRD, BET, FESEM, HR‐TEM, XPS, and Raman techniques. All studies confirmed the replication of porous MnO 2 nanostructures from silica supports in β‐crystallographic form. By employing X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS), we identified the existence of Mn and oxygen vacancies in the developed MnO 2 material. The hydrodynamic linear sweep voltammetric technique was employed to demonstrate the efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activity of the catalyst in 0.1 M KOH solution. The KIT‐6‐derived MnO 2 nanostructure displayed equal activity to the benchmark catalyst RuO 2 . This work lays a foundation to prepare and employ ordered mesoporous MnO 2 materials as OER/ORR catalysts, which have potential applications in electrochemical energy conversion and storage devices.