When Graphene Meets Nickel! Synergistic Laser Ablation of Nickel Oxide with Graphene Electrophoretic Deposition for a Robust Electrocatalytic Oxygen Evolution Reaction

The practical deployment of alkaline water electrolysis remains constrained by the sluggish kinetics of the oxygen evolution reaction (OER). Although the nickel oxide electrocatalyst exhibits strong intrinsic activity, its poor electronic conductivity and structural instability under high anodic bias limit sustained performance. Graphene is frequently employed as a conductive additive, and achieving its optimal integration without blocking active sites or pores remains a key unresolved challenge. We make an attempt to overcome these limitations by integrating picosecond laser-ablated NiO with electrophoretically deposited graphene to form a binder-free, hierarchically porous, and coupled heterointerface. Picosecond laser processing generates oxygen-deficient, high-surface-area NiO with exposed Ni redox centers, while controlled graphene electrophoretic deposition (EPD) establishes a continuous conductive network without obstructing catalytic accessibility. Two NiO base samples fabricated at low and high laser powers were further modified by EPD of graphene for 30 min at 5 and 2.5 V, and their OER performance was evaluated in 1 M KOH. A comprehensive mathematical model rationalizes the existence of an optimal graphene coverage window at lower EPD voltage and short-to-medium deposition times (∼30 min), where a continuous conductive network forms without blocking the porosity. The optimized NiO/graphene electrode (10 W laser power, 2.5 V EPD) delivers an overpotential of 347 mV at 10 mA cm –2, Tafel slope of 53 mV dec –1, and mass activity of ∼4000 A g –1, outperforming pristine NiO and many reported Ni-based TMOs. Chronoamperometry at 100 mA cm –2 shows exceptional stability over 70 h, attributed to graphene-assisted suppression of surface reconstruction and dissolution. The large-scale electrocatalyst synthesis and scalable electrode fabrication always remain as a significant challenge. This hybrid laser-EPD approach can make cost-efficient roll-to-roll manufacturing plausible, taking green hydrogen production toward widespread deployment.