Ga doped Ni3S2 ultrathin nanosheet arrays supported on Ti3C2-MXene/Ni foam: An efficient and stable 3D electrocatalyst for oxygen evolution reaction

Abstract

Exploring cost-efficient electrocatalysts for oxygen evolution reaction (OER) is still a huge challenge in the electrochemical energy conversion technology. In this work, Gallium (Ga)-doped Ni3S2 nanosheet arrays grown on Ti3C2-MXene/nickel foam (Ga–Ni3S2/Ti3C2/NF) have been synthesized by a successive hydrothermal and sulfidization process. The Ga doping modulates the electronic structure of Ni3S2, so tuning the adsorption energies of oxygen intermediate (∗OOH). The Ga–Ni3S2/Ti3C2/NF delivers outstanding catalytic activities toward OER with an overpotential of 340 mV at 100 mA cm−2, and exhibits superior electrochemical durability. The excellent OER performance of Ga–Ni3S2/Ti3C2/NF can be ascribed to the 3D sheet arrays morphology and optimized electronic structure. Density functional theory (DFT) calculations also demonstrate that electronic disturbance attributed to Ga doping effectively improves the activity of Ni sites, leading to stronger binding strength of ∗OOH intermediate at Ni sites nearby Ga. This study provides insights into the fabrication of advanced electrocatalysts for application.