Nickel molybdenum selenide on carbon cloth as an efficient bifunctional electrocatalyst for alkaline seawater splitting

Abstract

Exploring cost-effective and highly efficient electrocatalysts is desirable for the overall water-splitting challenge. In this work, a promising bifunctional electrocatalyst for oxygen evolution and hydrogen evolution reactions (OER/HER) in an alkaline medium (1 M KOH) and simulated alkaline seawater (1 M KOH + 0.5 M NaCl) was rationally developed by a simple, one-step, inexpensive, and eco-friendly method. Mo-doped nickel selenide supported on activated carbon cloth (NiMoSe@CC) was successfully synthesized via a hydrothermal method. NiMoSe nanoparticles were observed to be densely grown with better uniformity on the carbon fibers, as confirmed by different characterization techniques. The NiMoSe@CC showed an enhanced OER activity with a low overpotential of 320 mV (alkaline medium) and 360 mV (alkaline seawater) at 10 mA cm−2. The HER performance of the NiMoSe@CC was also the highest amongst NiMoSe, NiSe@CC, and MoSe@CC in both the alkaline and seawater environments. In addition, NiMoSe@CC bears a high electrochemically active surface area, low charge transfer resistance of 1.77 Ω, and high stability for both OER and HER. The NiMoSe@CC//NiMoSe@CC system was stable for 5000 LSV cycles with η10 values of 1.63 V (1st LSV cycle) and 1.71 V (5000th LSV cycle).