Optimized Bubble Dynamics of 3D-Printed Electrodes for Enhanced Water Splitting

Gas evolution plays an important role in water electrolysis, as sluggish bubble dynamics lead to blockage of active sites, reduced catalytic performance, and even detachment of the catalysts. In this work, we present a strategy to fabricate highly rough three-dimensional (3D)-printed Ni (3DPNi) electrodes with ordered flow channel structures, achieving exceptional catalytic performance through enhanced bubble detachment and transport dynamics. The rough surfaces enhance hydrophilic and aerophobic properties, suppressing bubble coalescence and accelerating bubble detachment dynamics. The ordered structures of 3DPNi serve as efficient bubble flow channels and effectively prevent bubble trapping, facilitating rapid bubble transport dynamics. Collectively, these features optimize bubble dynamics, significantly boosting catalytic performance for water electrolysis. Computational fluid dynamics simulations and visual experiments validate the improved bubble dynamics. When coated with NiFe-LDH (NiFe-LDH/3DPNi), a low overpotential of 238 mV is required to deliver 100 mA cm^-2 for OER. In overall water splitting, the NiFe-LDH/3DPNi || Pt plate setup requires a cell voltage of 1.86 V to achieve 1 A cm^-2 and demonstrates excellent stability over 100 h at this current density, indicating strong potential for practical applications.