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

Abstract

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 H2O 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.

A low-cost and large-area modular nickel electrode on aramid fabric for efficient solar-driven water electrolysis

“…3, 7 and S10†) possibly due to the localized OH − depletion within the sub-micrometer scale from the complex electrode surface. Overall, our upscaling efforts show that introducing nanostructured geometry to electrodes does not necessarily solve the mass transport limitation when used in a cell with a face-to-face parallel electrode configuration; instead, the nanostructured geometry escalates the voltage loss since ions (plus dissolved gas and bubble uptake, 70 which is not even considered in our study) have to be transported between the bulk of the electrolyte and the inner geometry of the nanostructures.…”

3D printed energy devices: generation, conversion, and storage

“…g Schematic of the fabrication of graphene-based capillary array. Reproduced with permission from Wiley (2023) 52 . h Schematic diagrams showing the preparation of 3DPNi and the surface functionalization of 3DPNi with C-Ni1-xO/3DPNi lattice structure.…”

“…However, by incorporating 1D CNTs between the 2D graphene nanosheets, increased flexural stiffness effectively addressed this issue. Additionally, bio-inspired catalyst support inspired by water transport mechanisms in capillary plants was reported 52 . A graphene-based capillary array was fabricated as a catalyst support using DLP (Fig.…”

Bubble Management for Electrolytic Water Splitting by Surface Engineering: A Review

“…In recent years, researchers have made significant progress in controlling bubble transport through inhomogeneous or bioinspired designs, aiming to improve the reaction efficiency. ,− Yu et al fabricated an aerophilic electrode using a cone shape by gradient etching on copper wire and hydrophobic treatment (Figure e). The resulting superhydrophobic electrode aids in gas adsorption, while the conical shape creates nonequilibrium Laplace pressure on the tip site and the root site, which propels the bubble to move from the tip to the root of the electrode surface .…”

“…The resulting superhydrophobic electrode aids in gas adsorption, while the conical shape creates nonequilibrium Laplace pressure on the tip site and the root site, which propels the bubble to move from the tip to the root of the electrode surface . Inspired by the water/nutrient transport in the capillary plants, Zeng et al designed a graphene-based capillary array with side holes as a catalyst support to manage the bubble release and water supply. Benefiting from this structure (planted with CoNi carbonate), a homemade cell can reach 10 mA cm –2 in 1.51 V.…”