Electrocatalytic synergies of melt-quenched Ni-Sn-Se-Te nanoalloy for direct seawater electrolysis

Abstract

The study focuses on the development of binary nanoalloys based on metal dichalcogenides (Sn<inf>30</inf>Se<inf>70</inf>, Ni<inf>30</inf>Te<inf>70</inf>) and quaternary nanoalloy (Ni<inf>15</inf>Sn<inf>15</inf>Se<inf>35</inf>Te<inf>35</inf>) using the melt quenching technique. The nanoalloys show extensive water splitting in fresh and real seawater. Sn<inf>30</inf>Se<inf>70</inf>-coated nickel foam achieved a benchmark current density of 349 mV for the oxygen evolution reaction (OER), while Ni<inf>15</inf>Sn<inf>15</inf>Se<inf>35</inf>Te<inf>35</inf>-coated nickel foam (NF) required only 185 mV for the hydrogen evolution reaction (HER) in 1 M KOH. The study also shows that a two-electrode system can achieve sustained total water splitting at higher current densities (1 A.cm?2). Modification with a CuS<inf>x</inf> layer over NF at the OER end facilitated faster kinetics and mitigated chlorine corrosion enabling direct seawater splitting at 1.26 V. Continuous direct splitting of seawater at 100 mA cm?2 for 120 h required only 1.88 V, showing an efficiency of 92.9 % for H<inf>2</inf> production in real seawater. © 2024 Elsevier B.V.