To have better understanding of radiochemical reactions among oxygen baking products in a fusion reactor, reactions in equimolar tritium molecule (T2) and carbon dioxide (CO2) were examined by laser Raman spectroscopy and mass spectrometry. After mixing them at room temperature, T2 and CO2 decreased rapidly in the first 30 minutes and then the reactions between them became much slower. As the predominant products of the reactions, carbon monoxide (CO) and tritiated water (T2O) were found in gaseous phase and condensed phase, respectively. However, there likely existed also some solid products that were thermally decomposed into CO, CO2, T2, T2O, etc. during baking up to 523 K.