Figure 1. Illustration of the preparation of Co-based
flow-through electrodes (A).
The
morphology of the pore surface of Ni foam (B), raw CoB/Ni flow-through
electrode (C), and CoB/Ni flow-through electrode after HER activation
(D) and OER activation (E).
2.3. Electrochemical measurements
Electrochemical measurements were performed in a custom two-compartment
H-cell with cathode and anode compartments separated using an anion
exchange membrane (AEM, Fumasep FAA-3-50) using a CHI 660E
electrochemical workstation. A three-electrode configuration was
employed with CoB/Ni flow-through electrode as the working electrode, Ti
mesh coating with Pt as the counter electrode, and a Hg/HgO reference
electrode, as shown in figure S1. Among those, the CoB/Ti membrane
electrode was put in a self-made module with a module made of PTFE, a Ti
ring as a current collector, and a silicone
seal. The electrolyte flow rate
was controlled by a peristaltic pump and recirculated in the
corresponding compartment of the cell. We calculated the current density
by electrode area (0.785 cm2, based on the seal’s
inner diameter). All measurements were performed at room temperature.
The electrolyte (1 M KOH) was purged with dry N2 15
minutes before. All reported potentials were calibrated by an RHE based
on the following equation:
The volume of H2 and O2 generated from
cathode and anode cells was collected by the Drainage method. Before the
hydrogen/oxygen evolution starts, the electrode was subjected to
continuous CV scans until stabilized CV curves were observed. After
electrochemical activation, the electrodes are named according to the
active substance obtained by in-situ reconstitution.