Disproportionation of hydrogen peroxide
In principle you could find a lot of equations, all leading to the same result. But these are only (half-)equations. Most of the times the reaction mechanism is much more complicated than just these reaction equations.

The decomposition of hydrogenperoxide is still an active field of research in various media with various catalysts.

Unfortunately with the massive overflow of the above, I was only able to find a quite old PhD thesis by Trice Walter Haas (Iowa State University, 1960)

Here is a small line-up of reaction equations that will play a role in the decomposition, at least to that part that I can imagine it. And I am just assuming that there are radicals involved, because there usually are.
\begin{align}
\ce{H2O2 &amp;&lt;=&gt; H+ + HO2- }\\
\ce{HO2- + H2O2 &amp;&lt;=&gt; HO2 + HO + OH-}\\
\ce{HO2 + OH &amp;&lt;=&gt; H2O + O2}\\
\end{align}