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

Abstract

Herein, a novel boron-doped carbon sphere (BCS) and its derived MnO2 nanocomposite electrode (abbreviated MnO2/BCS) are prepared via a facile hydrothermal strategy, which was successfully confirmed via a combined characterization including scanning electron microscopy, tunneling electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared analysis, and Raman and X-ray photoelectron spectroscopy. With the introduction of BCS, 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 oxygen evolution reaction (OER) performance than does pristine MnO2. The electrochemical measurements demonstrate that optimal MnO2/BCS0.08 can give rise to the lowest overpotential (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 is mainly due to the higher conductivity, faster charge transfer kinetics, and higher electrocatalytic active sites of the MnO2/BCS0.08 compared to other counterparts. The incorporation of BCS is mainly responsible for the enhanced electrocatalytic activity. MnO2/BCS0.08 also has a prominent long-term stability in alkaline conditions. This work demonstrates an effective strategy for enhancing OER performance of MnO2 by incorporation of carbon nanomaterials.

Lithium Electrochemical Tuning Engineering in an Aqueous System of LiCoO2 for Enhanced Oxygen Evolution Activity

“…[1][2][3][4][5] Clean and sustainable energy technologies like water electrolysis and rechargeable metal-air batteries have drawn massive attention in an attempt to address the energy crisis. [6][7][8][9] Unfortunately, as the rate-limiting reaction of the above energy conversion devices, oxygen evolution reaction (OER) involves multi-step electron transfer processes resulting in slow kinetics and large polarization voltages, [10][11][12] which severely limits the overall efficiency of these technologies. [13][14][15][16] In this regard, various efficient and durable OER electrocatalysts have been explored for reduce overpotential and accelerate the reaction kinetics.…”

In Situ Formed Edge-Rich Ni3S2-NiOOH Heterojunctions for Oxygen Evolution Reaction

“…supported transition metal catalysts have attracted wide concern. [12][13][14][15][16][17][18][19] Recently, transition metal sulfides (TMSs, such as NiS 2 , Co 1-x S, Ni 3 S 2 , Co-MoS 2, etc.) with abundant sources, low cost, and environmentally benign nature have been reported as promising electrocatalysts towards OER.…”