Shouldn't it take more energy to break CO2 compared to CO?
The bonds are not equivalent, therefore they have different bond energy.


  Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond that consists of two covalent bonds as well as one dative covalent bond.It is the simplest oxocarbon and is isoelectronic with other triply-bonded diatomic molecules having ten valence electrons, including the cyanide anion, the nitrosonium cation and molecular nitrogen. In coordination complexes the carbon monoxide ligand is called carbonyl.


Source: Wikipedia page on Carbon Monoxide