Solving Redox Equations: Cathodic Reaction of Oxygen

[big man]

Homework Statement

Write the half equation for the cathodic reaction of oxygen

The Attempt at a Solution

Now I know that the cathodic reaction will be reduction and so the oxygen will be gaining electrons. I thought I had the answer from the lecture notes, but then I thought of another possible equation that would work too and I don't know which one is right??

The two equations are as follows:
equation from notes( the notes say that this is the most common)
O_2 + 2H_2O + 4e^- ->4OH^-

the equation I came up with
O_2 + 4H^+ + 4e^- ->2H_2O

Are these just two possible half equations for the cathodic reaction of oxygen or is one wrong??

Thanks for your time

 

[Gokul43201]

I think we need more context here. Both reactions are legal, and likely occur at quite different potentials, so additional details are necessary.