NH3 decomposition over Ru/CeO2-PrOx catalyst under high space velocity conditions for an on-site H2 fueling station

From a commercialization perspective, NH3 decomposition catalysts used in on-site H2 fueling stations require a high NH3 conversion of over 99.5%, space velocity (SV) of 30,000 h-1 and reaction temperature of 500 degrees C. To achieve this target, we present Ru catalysts supported on CeO2- PrOx composites (Ru/CP) prepared by a coprecipitation method. The Ru/CP catalysts exhibited higher activity than the Ru/CeO2 and Ru/PrOx catalysts and achieved the target with Pr content (=Pr/(Ce+Pr)) of 33-67%. STEM observations and in situ X-ray absorption fine structure analysis revealed that an increase in the Pr content in the catalysts improved the Ru dispersion but inhibited the Ru metalation, owing to a strong metal-support interaction. Notably, 10% of Ru in the Ru/PrOx remains an oxide even when reduced at 550 degrees C. These results suggest that both Ru dispersion and metalation are enhanced at the optimal Pr content, maximizing the number of Ru active sites.

Automated summary

To meet commercialization requirements, researchers prepared Ru catalysts supported on CeO2-PrOx composites (Ru/CP) by a coprecipitation method. The Ru/CP catalysts showed higher activity than Ru/CeO2 and Ru/PrOx catalysts, achieving over 99.5% NH3 conversion, a space velocity of 30,000 h-1, and a reaction temperature of 500 degrees C. Increasing the Pr content in the catalysts improved Ru dispersion but inhibited Ru metalation, maximizing the number of Ru active sites.