In water, O is sp3 hybridized. Due to stronger lone pairlone pair repulsions than bond pair-bond pair repulsions, the HOH bond angle decreases from 109.5° to 104.5°.
Thus water molecule has a bent structure.
H2O2 has a non-planar structure. The O – H bonds are in different planes.
Thus, the structure of H2O2 is like an open book.