Studies on Capillary‐Induced Electrolyte Flow Phenomenon for Hydrogen Production in Acidic Media

Effective water electrolysis is the key component of a future hydrogen economy based on renewable energy. Notwithstanding progress in water electrolysis, difficulties persist in acidic systems owing to efficiency losses, bubble formation, and intricate circulation. By employing a silica‐based separator to show the first effective acidic capillary‐fed electrolysis, this study simplifies design and improves performance by permitting passive electrolyte transfer and bubble‐free operation without the need for PEMs or forced circulation. Pt and IrO 2 electrocatalysts were prepared on the titanium substrate through the electrodeposition process. The capillary‐fed cell achieved a current density of 322 mA cm −2 at a constant cell voltage of 2 V at 30 °C, with 74% energy efficiency and 98% Faradaic efficiency, resulting in an energy consumption of 54.04 kWh kg −1 of hydrogen. The cell temperature, applied torque pressure, and separator thickness inside the cell played a critical role in enhancing the performance of the capillary‐fed cell. The electrolyte absorption through the separator occurred by the combined effect of capillary action and electrolysis‐induced diffusion. This study highlights the novelty of deploying a silica‐based AGM separator in acidic electrolysis, providing a simple, low‐cost, and sustainable pathway for green hydrogen production by reducing the bubble resistance and electrolyte circulation costs.