In Situ Construction of Hierarchical Nanoflower-Like MnO2/Biomass-Based Boron-Doped Carbon Spheres for Oxygen Evolution Reaction

Herein, a novel boron doped carbon sphere (BCS) and its derived MnO2 nanocomposite electrode (abbreviated as MnO2/BCS) are firstly prepared via a facile hydrothermal strategy, which was successfully confirmed via a combined characterization including SEM, TEM, EDS, FT-IR, Raman and XPS. Due to the introduction of BCS, the MnO2/BCS shows hierarchical nanoflower-like morphology with a smaller particle size and higher specific surface area than that of pristine MnO2. Importantly, the resultant MnO2/BCS with proper addition of BCS displays superior OER performance than those of the pristine MnO2. The electrochemical measurement results demonstrate that the optimal MnO2/BCS0.08 can give rise to a lowest overpotential mere 170 mV at 10 mA-cm(-2), onset potential reaching 1.33 V together with smallest Tafel slope value of 31.43 mV dec(-1), which can be mainly due to the higher conductivity, faster charge transfer kinetics and higher electrocatalytic active sites of the MnO2/BCS0.08 than those of other counterparts. Undoubtedly, the incorporation of BCS is mainly responsible for the enhanced electrocatalytic activity. Furthermore, the MnO2/BCS0.08 also has a prominent long-term stability in alkaline conditions. In conclusion, our present work demonstrates an effective strategy to enhance the OER performance of MnO2 by incorporation of the carbon nanomaterials. (C) 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.