The heat of formation of CO2 is - 407 kJ/mol. The energy required for the process, 3CO2g)  → 3C(g) + 2O3(g) is

3CO2(g)→3C(g)+2O3(g)ΔH=3ΔHatomization C(s)→C(g)+2ΔHf∘O3(g)−3ΔHf∘CO2(g)ΔH=3ΔHatomization C(s)→C(g)+2ΔHf∘O3(g)+3×407As energy will be required for the processesC(s)→C(g) and 3O2(g)→2O3(g).'. ∆H will be more than 1221 kJ.