In this study, the abilities of carbon and silicon nanocages (C78 and Si78) and carbon and silicon nanotubes (CNT (9, 0) and SiNT (9, 0)) as catalysts of CO2-RR are investigated. The calculated Eadoption values of Fe-C78, Fe-Si78, Fe-CNT (9, 0) and Fe-SiNT (9, 0) nanostructures by DFT functional are -3.00, -3.12, -3.43 and -3.59 eV. The COSMO model has been used to calculate the effects of water as polar solvent on potential of Fe-doped nanostructures and their complexes with CO2-RR species. The calculated ∆Greaction values of *OCO → *OCHO on Fe-C78, Fe-Si78, Fe-CNT (9, 0) and Fe-SiNT (9, 0) nanostructures by DFT functional are -0.33, -0.35, -0.37 eV. The production of *OCHO and *COOH on surface of Fe-SiNT (9, 0) as catalysts has more negative ∆Greaction value than Fe-C78, Fe-Si78 and Fe-CNT (9, 0). The Fe-C78, Fe-Si78, Fe-CNT (9, 0) and Fe-SiNT (9, 0) can catalyze the CO2-RR with suitable performances.