A flow-through electrode for hydrogen production from water splitting by mitigating bubble induced overpotential

Bubble evolution induced overpotential for hydrogen production by water electrolysis is an important issue and the internal/external surface of the electrode can be covered by the generated bubbles. Herein, flow-through electrodes with in-situ restructured Co-based nanosheets loaded in Ni foam pores are presented. The adhesion between H2 bubbles and the superaerophobic catalyst layer is reduced from 14.2 μN to about zero and H2 bubbles size is reduced from 41.76 μm to 23.17 μm. Under the condition of flow-through mode, the catalysts can be adequately exposed because the generated bubbles can be timely removed from the catalyst surface. The overpotential can be reduced by about 100 mV for hydrogen evolution reaction (HER) and 57 mV for oxygen evolution reaction (OER) under the condition of 300 mA cm−2 and electrolyte flux of 339 m3 m−2 h−1. A novel electrolyzer assembled with flow-through electrode for hydrogen production by alkaline water electrolysis is conducted. The cell voltage can be decreased by 50 mV at 200 mA cm−2 at 6 M KOH, 338 K, and 1 atm, with the energy of 4.42 kW h Nm−3 required. The results provide insights into the design of various electrodes for electrolyzer setups that can be used for gas-involving reactions.