In order to improve the generation amount of nitrous oxide (N2O), the process of nitrite (NO2-) reduction was studied by Fe(II-III) carbonate green rust (GR(CO32-)). The results indicated that 97.1% NO2- was degraded, and over 71.3% N2O was achieved by the oxidation of GR(CO32-) to Fe3O4; 14.1% N-2, 4.7% NH4+ and 3.0% NO3- were also formed in the denitrification process; the removal efficiency for total nitrogen (TN) was 89.6%; the optimal reaction condition was NO2- 10.71 mM, pH 9.5 and an initial E-h (the maximum value of E-h reached at the beginning of the process) of -473 mv. The generation of different reduction products was dependent on the initial E-h of the reaction system. Based on the adjustment of initial E-h, the formation order of reduction products was as follows: N2O, N-2 and NH4+. Additionally, compared with initial nitrite concentration, pH played a decisive role in the initial E-h of the NO2-/GR(CO32-) system. The high amount of N2O generated by the adjustment of initial E-h provides new insight into the NO2-/GR(CO32-) system. (C) 2016 Elsevier B.V. All rights reserved.