Ni3S2 nanosheets decorated on NiCo2O4 flakes-arrays directional growth of Ni foam for enhanced electrochemical hydrogen generation

Abstract

• NiCo 2 O 4 /Ni 3 S 2 /NF core–shell arrays on Ni foam were constructed by Ni 3 S 2 loaded on NiCo 2 O 4 arrays. • The hierarchical nanostructures of NiCo 2 O 4 /Ni 3 S 2 /NF contribute excellent activity and stability for HER. • NiCo 2 O 4 /Ni 3 S 2 /NF provides large active sites and faster charge transfer. Electrochemically production of hydrogen is an appealing approach to provide clean energy at an affordable price. Much research has been assigned to the development of functional catalysts that are efficient electrocatalysts for the hydrogen evolution reaction (HER). In this study, the nanocomposite catalyst composition of Ni 3 S 2 /NiCo 2 O 4 on nickel foam as a non-noble-metal has been prepared via a convenient chemical conversion route. The synthesized catalyst demonstrates excellent stability and durability in aqueous environments, which makes it a very active, stable, low-cost and promising catalytic system in the field of energy analysis, conversion and storage. Here, the prepared electrode to achieve a current density of 10 mA cm −2 requires an overpotential of 184 mV with a Tafel slope of 97 mV dec -1 in alkaline solution (1 M KOH) and an overpotential of 140 mV with a Tafel slope of 53.6 mV dec -1 in acidic condition (0.5 M H 2 SO 4 ). The catalytic system's activity can be maintained for at least 14 h in KOH 1 M and H 2 SO 4 0.5 M. Also, the present work investigates the electrochemical characterization of the samples in which the current density is normalized by geometric area, electrochemical active surface area (ECSA) and BET specific surface area.