Juan Jian,Long Yuan,Hui Qi,Xuejiao Sun,Le Zhang,He Li,Hongming Yuan,Shouhua Feng
Ni3S2 nanosheets doped with tin (Sn) grown on nickel foam (Sn–Ni3S2/NF) through a facile hydrothermal process were found to be superior water-splitting electrocatalysts. As for overall water splitting (OWS), when the current density is 10 mA cm–2, the required voltage is only 1.46 V. Meanwhile, it exhibits a large current density property and long-time stability (>60 h current–time tests) for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In order to reach the current densities of 100 and 1000 mA cm–2, Sn–Ni3S2/NF needs overpotentials of 0.17 and 0.57 V for HER, and 0.27 and 0.58 V for OER, respectively. The water-splitting property of Sn–Ni3S2/NF is much better than that of pure Ni3S2/NF or even 20 wt % Pt/C/NF and RuO2/NF. Furthermore, Sn–Ni3S2/NF showed a higher turnover frequency at different potentials, with ∼100% Faraday efficiency for both O2 and H2. The improved activity of Sn–Ni3S2/NF activity for water-splitting is attributed to the doping of Sn, which enhanced the intrinsic activity of Sn–Ni3S2/NF for OWS. This article not only provides a new efficient and stable catalyst for OWS, but also proposes an interface design principle for NF-based high-performance water-splitting materials.
Designing noble metal-free electrocatalysts remains a challenge for the oxygen evolution reaction (OER) in alkaline solutions. In this study, we present a facile electrodeposition approach coupled with an in situ anodic oxidation method to synthesize NiOOH–MnS/NF on nickel foam (NF), successfully creating NiOOH–MnOOH/NF heterojunctions to boost OER performance under alkaline conditions. The heterojunction's synergistic effect significantly modulates the adsorption energy of the rate-determining step (RDS), thereby enhancing the intrinsic electrocatalytic activity of the NiOOH–MnOOH/NF electrocatalyst. Furthermore, the introduction of SO42− leads to a variable degree of electron loss in both Mn and Ni, reducing adsorption strength of the OER intermediates and thus optimizing reaction kinetics. The as-prepared NiOOH–MnOOH/NF electrocatalyst demonstrates exceptional OER performance in 1.0 M KOH, achieving a current density of 100 mA cm−2 with a Tafel slope of 52.3 mV dec−1 and a minimal overpotential of 391 mV. Utilizing NiOOH–MnOOH/NF as a bifunctional electrode for overall water splitting (OWS), the system operates at a low potential of 1.66 V at 10 mA cm−2, showcasing its excellent durability. This work offers novel insights and promising prospects for the advancement and practical application of non-precious metal electrocatalysts in the field of electrocatalytic water splitting.
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