Hence, the lower the flow rate, the smaller app Ea becomes. The very small change in reaction conditions significantly affects app Ea. 4.7 Coverage effect on app Ea. To further illustrate the relationship between coverage and app Ea, the relationship between app Ea and coverage for each adsorbed species is shown in Figure9. Figure (i) shows that app Ea over Ru decreases as 𝜃 V increase. The 𝜃 V dependence of app Ea was unclear (Figure (iii)). On the other hand, app Ea increases as 𝜃 H increases (Figure (v)). This indicates that hydrogen poisoning of Ru increases app Ea, while an increase of and 𝜃 𝑁 2 on the surface decreases app Ea. Therefore, the importance of suppressing hydrogen poisoning on Ru-based catalysts was demonstrated. In addition, it was experimentally shown that app Ea is affected by the coverage. The app Ea of Ru+K also showed a dependence on coverage (Figure (ii) (iv) (vi)). Similar to Ru, the overall trend was that app Ea increased as 𝜃 H increased, and app Ea decreased as θN increased. In contrast, for Ru+K, the relationship between coverage and app Ea was not as clear as for Ru: since the RDS changes with temperature for Ru+K (Table ), the temperature dependence of the coverage also differs significantly from that for Ru (Fig. ), and the relationship between app Ea and coverage is not as clear as for Ru.