Nanostructured manganese oxide on fullerene soot for water oxidation under neutral conditions

Abstract

The sluggish kinetics of oxygen-evolution reaction (OER) through water-oxidation reaction results in high overpotentials for water splitting. Among different compounds, carbon-based material/Mn oxide composites were reported as OER catalysts. Fullerene soot (FS), which contains a mixture of fullerenes and carbon blacks, is low-cost compared to fullerenes and is commercially available. Herein, the Mn oxide/fullerene soot (MnO<inf>x</inf>/FS) composite was investigated as an OER catalyst under neutral conditions. The composite was prepared through the reaction of KMnO<inf>4</inf> and FS as a facile, easy, and low-cost procedure. In this method, amorphous Mn oxide is formed directly on FS. The material was characterized by a number of methods. Then, the OER catalytic activity of MnO<inf>x</inf>/FS was studied in a LiClO<inf>4</inf> solution (pH ≈ 6.3). Compared to pristine FS, the OER activity of MnO<inf>x</inf>/FS is 2.5 times higher at 2.25 V vs. RHE. The Tafel slopes for OER are 450 and 240 mV per decade for FS and the reported composite, respectively. © 2023 Elsevier B.V., All rights reserved.