Exploring Synergy: Pd/H_<i>y</i>Mn_0.8Co_0.2O₂ Nanocomposite for Enhanced Overall Water Splitting toward Sustainable Green Hydrogen Production

HyMn0.8Co0.2O2 nanosheets (HyMnCoO2 NS) exhibit encouraging electrocatalytic Hydrogen Evolution Reaction (HER) activity but limited Oxygen Evolution Reaction (OER) performance in an alkaline medium. However, the incorporation of palladium nanoparticles (Pd NPs) onto the HyMnCoO2 NS demonstrates improved and stable HER/OER as well as overall water splitting (OWS) by the composite (Pd/HyMnCoO2). A strongly coupled metal/metal oxide synergy imparts efficient bifunctional catalytic activity in the composite. The Pd/HyMnCoO2 composite achieves a current density (j) of 10 mA cm–2 in a 1.0 M KOH electrolyte with an applied overpotential of 210 mV for HER and 390 mV for OER and retains stable performance for ∼24 h. A two-electrode Pd/HyMnCoO2||Pd/HyMnCoO2 electrolyzer efficiently performs the OWS at a cell voltage of 2.0 V, operating continuously for ∼120 h without significant change in current density, highlighting a cost-effective and scalable electrolyzer fabrication. Enhanced mass activity (MA), electrochemical active surface area (ECSA), turnover frequency (TOF), and Faradaic efficiency (FA) underscore the catalyst’s potential for practical applications. X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and density functional theory (DFT) studies reveal strong interfacial coupling between Pd NPs and HyMnCoO2 NS, modulating the electronic structure and enhancing catalytic activity. This work underscores the promise of a strongly coupled metal/metal oxide system as an economical alternative to a fully noble metal-based electrocatalyst for water splitting applications. The Pd/HyMnCoO2||Pd/HyMnCoO2 electrolyzer when connected to a 3.00 V solar panel under daylight demonstrates encouraging OWS paving the way for sustainable green hydrogen production.