The activity shows a steep increase and reaches a plateau after 40 h time on stream. Afterwards, the temperature was varied between 30 °C and 90 °C in 10 °C steps, with stable activity and selectivity for each temperature (Figure The increase in activity with time at constant temperature and feed composition might indicate the reduction of remaining oxidic species on the surface and the formation of the active species under reaction conditions. The oxidic species originates from contact with air as the reduced catalyst is transfered from the reduction furnace to the reactor. The reducing reaction conditions seem to be able to reduce the catalyst surface in situ at 90 °C. Therefore, the synthesized catalysts with 1 wt%, 5 wt% and 10 wt% iron loading were tested in the acetylene hydrogenation following the same reaction protocol: