A zoned reactor for the reforming of NH 3 to N 2 and H 2 , wherein the reactor is an adiabatic rector, and wherein the reactor comprises a reactor inlet and a reactor outlet, the reactor inlet and the reactor outlet being separated by the axial length L of the reactor, and n reaction zones arranged in sequence and extending from the reactor inlet to the reactor outlet along the axial length L of the reactor, wherein n is an integer in the range of from 2 to 5, wherein the length of each of the n reaction zones in axial direction constitutes a fraction of the length L of the reactor, wherein the sum of the lengths of all of the reaction zones in axial direction is less than or equal to L, wherein independently from one another, each of the n reaction zones comprises one or more catalytic components, wherein the inlet reaction zone which is adjacent to the reactor inlet displays a higher light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 than each of the one or more subsequent reaction zones downstream thereof, wherein the outlet reaction zone which is adjacent to the reactor outlet displays a lower light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 than each of the one or more preceding reaction zones upstream thereof, and wherein each of the optional intermediate reaction zones between the inlet and outlet reaction zones respectively displays a light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 which is lower than each of the one or more preceding reaction zones upstream thereof and which is higher than each of the one or more subsequent reaction zones downstream thereof, wherein the T50 light-off temperature is determined according to Reference Example 1. a reactor inlet and a reactor outlet, the reactor inlet and the reactor outlet being separated by the axial length L of the reactor, and n reaction zones arranged in sequence and extending from the reactor inlet to the reactor outlet along the axial length L of the reactor, wherein n is an integer in the range of from 2 to 5, wherein the length of each of the n reaction zones in axial direction constitutes a fraction of the length L of the reactor, wherein the sum of the lengths of all of the reaction zones in axial direction is less than or equal to L, wherein independently from one another, each of the n reaction zones comprises one or more catalytic components, wherein the inlet reaction zone which is adjacent to the reactor inlet displays a higher light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 than each of the one or more subsequent reaction zones downstream thereof, wherein the outlet reaction zone which is adjacent to the reactor outlet displays a lower light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 than each of the one or more preceding reaction zones upstream thereof, and wherein each of the optional intermediate reaction zones between the inlet and outlet reaction zones respectively displays a light-off temperature T50 in the reforming of NH 3 to N 2 and H 2 which is lower than each of the one or more preceding reaction zones upstream thereof and which is higher than each of the one or more subsequent reaction zones downstream thereof, wherein the T50 light-off temperature is determined according to Reference Example 1. <EOS>