Development of high-performance cobalt oxide electrocatalysts for alkaline water splitting via integrated pulsed laser ablation in liquid (PLAL) and electrophoretic deposition (EPD)

Hydrogen is increasingly recognized for its potential to address global energy and environmental challenges. Among the various hydrogen production methods, water electrolysis powered by renewable energy is particularly emphasized as a sustainable and eco-friendly approach. However, its widespread adoption is hindered by issues such as low efficiency, high overpotentials, and dependence on costly noble metal catalysts. To address these challenges, this study proposes a novel strategy for fabricating nanoparticle (NP)-based electrocatalytic electrodes with enhanced electrochemical activity by combining pulsed laser ablation in liquid (PLAL) and electrophoretic deposition (EPD). PLAL offers a green synthesis route for NPs with controlled size and high zeta potential, while EPD enables uniform deposition and structural optimization of the catalyst layer. By fine-tuning the EPD deposition time, stable cobalt oxide catalyst coatings with dense, uniform, and well-crystallized structures were successfully achieved. The fabricated electrode exhibited significant reductions in overpotential—33 % for the hydrogen evolution reaction (HER) and 18 % for the oxygen evolution reaction (OER) at 10 mA/cm²—compared to electrodes made via conventional drop-casting methods. The electrode's excellent durability was further confirmed through chronoamperometry and linear sweep voltammetry (LSV) tests. The Co³⁺/Co²⁺ ratio, lattice oxygen, and oxygen vacancies were identified as key factors enhancing electrochemical performance. A comparison with reported cobalt oxide catalysts revealed the synergistic advantages of the PLAL-EPD strategy, highlighting its potential as an advanced technique for developing next-generation catalyst electrodes for water electrolysis.