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

Abstract 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.