For the development of renewable energy conversion and storage systems, it is vital to investigate earth-abundant, noble-metal-free, and highly efficient electrocatalysts for the hydrogen evolution process (HER). Platinum and other precious metals-based electrocatalysts show better HER activity in acidic conditions than other electrocatalysts due to their fast kinetics and lower Tafel slope.[1] However, because they are rare and costly, they are challenging to deploy in practical applications. As a result, there has been an ongoing search for low-cost and earth-abundant materials that may be used as an efficient alternative for platinum-based electrocatalysts, with the goal of developing more cost-effective and inexpensive H₂ manufacturing processes. The layered 2D nanomaterials have sparked a lot of scientific attention because of their tremendous potential for both fundamental and practical investigations. Natural minerals of the group V-VI (V = Bi, Sb; VI = S, Se) have exceptional optical and electrical characteristics.[2] Because of their availability, low cost, and tunable characteristics, antimony/bismuth-based chalcogenides are garnering a lot of attention as potential candidates as electrocatalysts for acidic HER. We have shown an efficient and straightforward approach for the electrochemical exfoliation of BiSbSe₃ nanostructures from the ball-milled BiSbSe₃ sample; the process parameters were adjusted in terms of time and applied voltage. Furthermore, a simple and straightforward electrophoretic deposition process was used to synthesize BiSbSe₃ nanoparticles from exfoliated BiSbSe₃ nanostructures. A DC voltage was supplied between the two inert electrodes in an aqueous electrolyte for the electrophoretic deposition of BiSbSe₃ nanostructures directly onto a gold substrate. Charged particles or sheets suspended in the electrolyte are activated to migrate toward the electrode and deposit when a voltage is applied. The BiSbSe₃ nanoparticles were deposited onto the positive electrode because the exfoliated BiSbSe₃ nanostructures in water had a negative zeta potential. BiSbSe₃ nanostructures prepared through electrochemical exfoliation method are electrophoretically deposited onto the gold substrate to obtain BiSbSe₃ nanoparticles, were investigated as active electrocatalysts for HER in 0.5 M H₂SO₄ solution using a three-electrode set up. The optimized BiSbSe₃ catalyst (10V10M-Au-7.5) is identified as highly active HER activity, having a low overpotential of 72 mV @ 10 mA cm⁻² and a low Tafel slope of 31.6 mV dec^-1, which far better than the antimony/bismuth chalcogenide system and very close to the state-of-the-art Pt/C catalyst. We demonstrate that the electrocatalytic HER activity is enhanced by highly active edge sites, large available surface active sites, defects created and partial oxidization of material during electrodeposition, and a synergistic effect between BiSbSe₃ and the substrate.

References

[1] N.P. Dileep, T.V. Vineesh, P. V Sarma, M. V Chalil, C.S. Prasad, M.M. Shaijumon, Electrochemically Exfoliated β-Co(OH)2 Nanostructures for Enhanced Oxygen Evolution Electrocatalysis, ACS Appl. Energy Mater. 3 (2020) 1461–1467. https://doi.org/10.1021/acsaem.9b01901.

[2] J. Wang, H. Yu, T. Wang, Y. Qiao, Y. Feng, K. Chen, Composition-Dependent Aspect Ratio and Photoconductivity of Ternary (Bi_xSb_1–x)₂S₃ Nanorods, ACS Appl. Mater. Interfaces. 10 (2018) 7334–7343. https://doi.org/10.1021/acsami.7b17253.