Ni-tethered MoS2: In-situ fast reduction synthesis as an ultra-durable and highly active electrocatalyst for water splitting and urea oxidation

Abstract

Developing an extraordinarily robust and efficient green electrocatalyst derived from earth-abundant elements is becoming an important part of green hydrogen generation. We present here a simple single-step in-situ fast reduction synthesis of Ni-tethered MoS2 (NiMoS2), which exhibits excellent activity for the Oxygen Evolution Reaction (OER), Hydrogen Evolution Reaction (HER), and Urea Oxidation Reaction (UOR). To supply 10 mA cm−2 current density, the active catalyst NiMoS2 exhibits minor overpotentials of 141 mV vs RHE (reversible hydrogen electrode) for HER, and 250 mV vs RHE for OER in 1.0 M KOH. NiMoS2 displays ultra-durability (over 90 h) with a current loss of <4.6% for OER and <3.6% for HER, respectively. The enhanced trifunctional catalyst NiMoS2/NF enables the construction of a stable behavior water electrolyzer that delivers 10 mA cm−2 at 1.52 V. With a <4.8% current loss, the NiMoS2/NF//NiMoS2/NF exhibits an ultra-stable behavior (over 150 h). The water electrolysis at 1.64 V with solar assistance demonstrates the enhanced efficacy of the synthesized catalyst. The fabricated electrode, NiMoS2 exhibits efficient catalytic activity toward the electro-oxidation of urea (UOR) (1 M KOH +0.33 M urea) at 1.39 V.