Question

Why oxygen bubbles are larger than hydrogen bubbles during water electrolysis?

Answer 1

During water electrolysis, I found the oxygen bubbles are usually larger than the hydrogen bubbles.

I think the reason is because different gases have different contact angles. The contact angle of the oxygen is larger than the hydrogen that cause the size of oxygen bubbles are lager than the hydrogen bubbles.If my assumption is right, could you please explain why the contact angle is different for different gases?

I have captured some videos that can prove the oxygen bubbles are larger than hydrogen when they are going to detach from the surface.