Peroxisomes definition varies, do they exist before mitochondria and acts as an ATP synthesis organelle?
Have a look at a brief description of peroxisome function in MBoC Peroxisomes or MCB Peroxisomes Degrade Fatty Acids and Toxic Compounds “…oxidation of fatty acids in mitochondria, which produces CO2 and is coupled to generation of ATP, peroxisomal oxidation of fatty acids yields acetyl groups and is not linked to ATP formation.” There are several theories as to their (evolutionary) origin and you do not need to know the biochemical pathways they utilise, just the overall function of peroxisomes.
