Figure 2. High-resolution spectra of Co (A), O 1s (B), and B 1s (C) of CoB/Ni flow-through electrode before and after HER/OER activation.
The AWE performance of each prepared electrode has been investigated in 1 M KOH solution. In this study, three different pore sizes of Ni foam have been chosen, with 35, 75, and 110 PPI. The thickness of each Ni foam is 1 mm, and the diameter of each Ni foam is 10 mm. The linear scan voltammetry (LSV) polarization curves (Figure 3A, Figure S6) were used to assess the performance of AWE at a scan rate of 5 mV s-1. As can be seen, the catalytic performance can be enhanced after loading catalysts, with a reduction in the potential of almost 150 mV at 400 mA cm-2. The best catalytic performance can be achieved by Co(OH)2/Ni electrode with a pore size of 75 PPI (Figure S7-S10), due to the largest electrochemical surface area (ECSA, 38.38 mF cm-2) and the smallest reaction resistance (6.481 ohm).