The mechanisms of N2O reduction via SiO on surfaces of P-doped carbon nanotube (CNT) and Si-doped boron nitride nanotube (BNNT) by density functional theory were investigated. The P and Si adsorption energies on surfaces of CNT and BNNT were calculated to be -314.6 and -347.2 kcal/mol, respectively. The decomposition of CNT-P-N2O and BNNT-Ge-N2O and reduction of CNT-P-O* and BNNT-Ge-O* by SiO molecule were investigated. The BNNT-Ge-O* has lower activation energy and more negative Delta G(ad) rather than CNT-P-O* and therefore the process of BNNT-Ge-O* + SiO -> BNNT-Ge+SiO2 was spontaneous more than CNT-P-O* + SiO -> CNT-P+SiO2 from thermodynamic view point. Results show that activation energy for BNNT-Ge-O* + N2O. BNNT-Ge-O-2 + N-2 and CNT-P-O* + N2O -> CNT-P-O-2+N-2 reactions were 27.89 and 31.56 kcal/mol, respectively. The results show that P-doped CNT and Ge-doped BNNT can be observed as a real catalyst for the reduction of N2O. (C) 2017 Elsevier B.V. All rights reserved.