3D Microporous Structure with Tunable Surface Roughness Enables Fast Bubble Dynamics for Efficient Water Splitting.

Water splitting serves as a cornerstone technology in modern energy conversion and storage systems. However, its industrial-scale implementation remains constrained by dynamic interfacial destabilization caused by intense bubble evolution under high current densities. Herein, a laser-assisted fabrication strategy is dveloped utilizing selective laser melting to construct 3D metallic electrodes with macro-micro synergetic architectures, enabled by precise laser energy density control for simultaneous optimization of water splitting and bubble transport dynamics. The engineered 3D microporous structure electrode integrates macro-scale 3D channels for accelerated mass transfer with micro-scale in situ-grown spherical substrates functionalized by nickel-iron layered double hydroxide (NiFe LDH) catalysts, establishing a hierarchical architecture denoted as NiFe LDH/3D printing (NF/3DP). Interestingly, Laser-tuned surface roughness confers superhydrophilicity, gas repellency, and low bubble adhesion. Collaborative 3D channel design significantly reduces concentration polarization and achieves efficient mass transfer at the solid-liquid-gas three-phase interface. Notably, the NF/3DP electrode only requires a 330 mV overpotential to drive the oxygen evolution reaction (OER) at an industrial current density of 1000 mA cm-2, and maintains initial activity even after continuous operation for 1000 h at 500 mA cm-2. This strategy supports flexible assembly like Lego through modular interface design, providing a standardized manufacturing and scalable technical solution for customized hydrogen production systems.