Textured NiSe2 Film: Bifunctional Electrocatalyst for Full Water Splitting at Remarkably Low Overpotential with High Energy Efficiency

Abdurazag T Swesi; Jahangir Masud; Wipula P R Liyanage; Siddesh Umapathi; Eric Bohannan; Julia Medvedeva; Manashi Nath

doi:10.1038/s41598-017-02285-z

Textured NiSe₂ Film: Bifunctional Electrocatalyst for Full Water Splitting at Remarkably Low Overpotential with High Energy Efficiency

Sci Rep. 2017 May 25;7(1):2401. doi: 10.1038/s41598-017-02285-z.

Authors

Abdurazag T Swesi¹, Jahangir Masud¹, Wipula P R Liyanage¹, Siddesh Umapathi¹, Eric Bohannan², Julia Medvedeva³, Manashi Nath⁴

Affiliations

¹ Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
² Materials Research Center, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
³ Department of Physics, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
⁴ Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, 65409, USA. nathm@mst.edu.

Abstract

Herein we have shown that electrodeposited NiSe₂ can be used as a bifunctional electrocatalyst under alkaline conditions to split water at very low potential by catalyzing both oxygen evolution and hydrogen evolution reactions at anode and cathode, respectively, achieving a very high electrolysis energy efficiency exceeding 80% at considerably high current densities (100 mA cm^-2). The OER catalytic activity as well as electrolysis energy efficiency surpasses any previously reported OER electrocatalyst in alkaline medium and energy efficiency of an electrolyzer using state-of-the-art Pt and RuO₂ as the HER and OER catalyst, respectively. Through detailed electrochemical and structural characterization, we have shown that the enhanced catalytic activity is attributed to directional growth of the electrodeposited film that exposes a Ni-rich lattice plane as the terminating plane, as well as increased covalency of the selenide lattice which decreases the Ni(II) to Ni(III) oxidation potential. Thereby, the high efficiency along with extended stability makes NiSe₂ as the most efficient water electrolyzer known to-date.