Phosphorus/sulfur co-doped heterogeneous NiCoPxSy nanoarrays boosting overall water splitting

In the large-scale implementation of renewable energy devices, the availability of stable and highly catalytic non-precious metal catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial. Meanwhile, integrating bifunctional electrocatalysts simultaneously on both the anode and cathode still faces challenges. To address this, a stepped preparation strategy was adopted on a nickel foam (NF) substrate to synthesize P, S co-doped NiCoPxSy nanowire array catalysts. The prepared NiCoPxSy catalysts demonstrated a small Tafel slope of 72.5 mV dec-1 for HER and 72.3 mV dec-1 for OER by requiring only 37 mV (326 mV) overpotential to achieve a current density of 10 mA cm-2 (50 mA cm-2). Moreover, when assembled into an electrolytic cell in 1 M KOH, the NiCoPxSy catalysts achieved a low voltage of 1.55 V at 10 mA cm-2 current density and exhibited long-term stability. The outstanding electrocatalytic performance can be attributed to the influence of doped anions on the electronic states and distribution among different atoms, which thereby positively affected the electrocatalytic activity. This research provides an effective method for designing innovative catalysts and paving the way to produce clean energy.