Steering ammonia decomposition over Ru nanoparticles on ZrO2 by enhancing metal–support interaction†

ZrO₂, one of the typical oxides, holds promise as a support for supported metal-based catalysts. Herein, Ru nanoparticles (NPs) on ZrO₂ (Ru/ZrO₂) analogues were prepared from milling and precipitation methods and applied in ammonia decomposition reaction. It was found that the Ru NPs in different Ru/ZrO₂ samples possessed similar particle sizes. Under identical reaction conditions, the Ru/ZrO₂ obtained from precipitation methods exhibits much higher activity than the Ru/ZrO₂ analogue with nearly identical Ru NPs on ZrO₂ obtained from the milling method. A hydrogen formation rate of 1439 mmol g_cat⁻¹ h⁻¹ and excellent stability were achieved over Ru/ZrO₂ catalyst from the precipitation method at 450 °C with a space velocity of 30 000 mL g_cat⁻¹ h⁻¹, comparable with many efficient Ru-based catalysts reported previously. The characterization results reveal that the superior catalytic performance of Ru/ZrO₂ from the precipitation method was mainly attributed to the modulated electronic structure of Ru NPs, which stems from the intimate interaction between Ru NPs and the ZrO₂ support. As a result, Ru/ZrO₂ from the precipitation method can facilitate the activation and dissociation of NH₃ molecules and exhibit greatly enhanced activity and intrinsic activity for NH₃ decomposition. This work offers opportunity for improving the catalyst performance by regulating the metal–support interaction of Ru-based NH₃ decomposition catalysts.