(334a) An Efficient and Novel Earth-Abundant Oxygen-Evolving Electrocatalyst Based on Self-Supported Amorphous Metal Boride

The oxygen evolution reaction (OER) at the anodic electrode occurs in electrochemical energy conversion and storage technologies, including rechargeable metal-air batteries, regenerative fuel cells, and water splitting. However, the state-of-the-art are precious metal-based catalyst which suffer from higher cost and makes them unsuitable for large-scale industrial application. Thus, developing low-cost, durable, earth-abundant, and high-performance non-precious metal electrocatalyst for oxygen evolution reaction (OER) is essential to improve the overall efficiency of water splitting. Electrochemically Hydrogen production has gained great interest over the past decades as a cleaner, higher-purity and sustainable production technology for carbon-neutral alternative fuel sources. Hydrogen is crucial for the future hydrogen energy technologies.¹ However, poor OER thermodynamic up-hill reaction limits the efficiency of H₂ production from water electrolysis and photoelectrolysis routes to large-scale energy storage. It is crucial to develop efficient and low-cost material to boost the sluggish kinetics step of four-electron OER process. Despite of a well-documented approach for synthesizing metal borides, its application as an OER electrocatalyst has not gained enough attention. Owing to the presence of boron which diminishes the thermodynamic and kinetic barrier of the hydroxylation reaction of the metal active centers, interest into the application of metal borides as efficient catalyst have emerged for this application and it is highly required to tailor its electrochemical properties.^{2, 3} However, the synergic effect had not been reported for multimetal borides material which was find to be the most OER among the reported metal borides materials.⁴ Herein, we investigate the OER electrocatalytic properties of a self-supported amorphous bimetallic borides nanostructure synthetized by a simple, one-step approach, yet exhibits robust electrochemical performance and outstanding stability in harsh alkaline condition. It exhibits an overpotential (η) of 237 mV to deliver a geometric current density (j_geo) of 10 mA cm^-2, a small Tafel slope of 38 mV dec^-1. The impressive electrocatalytic performance originates from the unique amorphous multimetal-metalloid complex nanostructure. From application point of view, this work holds great promise as this process is simple and allows for large scale production of cheap yet efficient material.

Keywords: Solar-driven Catalysis, Water Splitting, Electrocatalyst; Earth-abundant, Metal borides.

References

1. J. A. Turner, Science, 2004, 305, 972-974.
2. J. Masa, P. Weide, D. Peeters, I. Sinev, W. Xia, Z. Sun, C. Somsen, M. Muhler and W. Schuhmann, Adv. energy Mater., 2016, 6, 1502313-n/a.
3. H. Li, P. Wen, Q. Li, C. Dun, J. Xing, C. Lu, S. Adhikari, L. Jiang, D. L. Carroll and S. M. Geyer, Adv. Energy Mater., 2017, 7, 1700513-n/a.
4. J. M. V. Nsanzimana, Y. Peng, Y. Y. Xu, L. Thia, C. Wang, B. Y. Xia and X. Wang, Adv. Energy Mater., 2018, 8, 1701475.