Manageable Bubble Release Through 3D Printed Microcapillary for Highly Efficient Overall Water Splitting

Porous metal foams (e.g., Ni/Cu/Ti) are applied as catalyst supports extensively for water splitting due to their large specific area and excellent conductivity, however, intrinsic bubble congestion is unavoidable because of the irregular three‐dimensional (3D) networks, resulting in high polarization and degraded electrocatalytic performances. To boost the H(2)O decomposition kinetics, the immediate bubble removal and water supply sequential in the gas–liquid–solid interface is essential. Inspired by the high efficiency of water/nutrient transport in the capillaries plants, this work designs a graphene‐based capillary array with side holes as catalyst support to manage the bubble release and water supply via a Z‐axis controllable digital light processing (DLP) 3D printing technology. Like planting rice, a low‐cost, high‐active CoNi carbonate hydroxide (CoNiCH) is planted on support. A homemade cell can reach 10 mA cm(−2) in 1.51 V, and be kept at 30 mA cm(−2) for 60 h without noticeable degradation, surpassing most of the known cells. This research provides a promising avenue to design and prepare advanced catalysts in various fields, including energy applications, pollutant treatment, and chemical synthesis.