To experimentally demonstrate that the reaction order varies with temperature over Ru-based catalysts, the reaction order was measured at 380-460°C (Figure ). The N2 and H2 order of Ru were always about -1 and 1, respectively, regardless of temperature. The NH3 order of Ru is negative at high temperatures and approaches zero at lower temperatures. On the other hand, the NH3 order of Ru+K, like Ru, tends to approach 0 as the temperature decreases, but the H2 order, unlike Ru, becomes more negative as the temperature decreases. The reaction order shows different dependence on the catalyst. Figure and Table show that as the H2 order changes with temperature, the RDS also changes with temperature.