The accelerated depletion of fossil fuels has intensified research efforts towards designing materials capable for storage of electricity captured from sustainable but intermittent energy sources (e.g., wind and sunlight) in the form of chemical bonds (as H₂ fuel) through water splitting.¹ The water-splitting reaction can be divided into two half reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), among which the OER reaction is energetically more challenging and forms a major roadblock.² Many catalysts have been explored to expedite the reaction rate and lower the overpotential toward HER and OER.³ Transition metal chalcogenides (M_xE_y, M= Fe, Ni, Co; E = S, Se) have been recently identified as cost-effective, and efficient electrocatalysts for OER and HER energy conversion processes.^3-5

In this meeting, we will report on the electrocatalytic activity of a seleno-based metal coordination complex, [Ni{(SePⁱPr₂)₂N}₂] (1), which shows enhanced catalytic activity for both OER and HER in alkaline medium. The onset potential for O₂ evolution, as well as the overpotential at 10 mA cm^-2, was the lowest at 1.4 V and 200 mV, respectively (Fig. 1). The onset potential for H₂ evolution was also very low as compared to that of other non-Pt based HER electrocatalysts. A full water electrolysis could be achieved by coating both the cathode and the anode by this bifunctional catalyst, achieving a current density of 10 mA cm^-2at 1.8 V. This catalyst significantly enhances gravimetric current density (111.02 A/g) for OER process, thereby reducing the amount of active material required, without compromising the overal performance of the catalytic system.

References:

1. N. S. Lewis, D. G. Nocera, Proc. Natl. Acad. Sci. U. S. A., 2006, 103, 15729–15735.

2. J. O. Bockris, A. K. N. Reddy, Modern Electrochemistry, Vol 1: Ionics, (Ed.: J. O. Bockris), Springer, USA, 1998.

3. J. Masud, P. C. Ioannou, N. Levesanos, P. Kyritsis, M. Nath. ChemSusChem 2016, 22, 3128

4. A. T. Swesi, J. Masud, M. Nath, Energy Environ. Sci. 2016, 9, 1771

5. J. Masud, A. T. Swesi, W. P. R. Liyanage, M. Nath, ACS Appl.Mater. Interfaces 2016, 8, 17292.