Freezing of fluids confined at the nanoscale is of great importance for the understanding of their behaviour due to the confinement effects arising from the finite pore size and the surface forces. Experiments of confined fluids freezing on ordered mesoporous silicas have shown that they crystallise at a temperature below their bulk freezing point depending on the pore size. Surprisingly, our previous neutron measurements carried out at NIMROD showed that CO2 molecules confined in ordered porous silica (SBA-15), upon cooling below the bulk critical point (T3=216.6 K), neither freeze nor remain liquid, but escape from the pores. This depletion was for the first time observed. We are proposing to further investigate the behaviour of confined CO2 molecules, upon cooling, in silica samples with different pore structure (KIT-6) and pore size (MCM-48).