Ru-Based Catalysts for H<inf>2</inf> Production from Ammonia: Effect of 1D Support

Abstract

This study reveals the effect of the catalytic 1D supports (carbon, ceria, alumina and titanate) for ruthenium particles on the low temperature release of hydrogen from ammonia. While the state-of-art literature presents Ru/carbon nanotubes (CNT) as the most active catalyst, we found in this work that ruthenium supported on ceria nanorods (Ru/CeO2) catalyst exhibited activity over 8 times higher than the Ru/CNT counterpart system. This enhanced activity is believed to be related to a strong metal-support interaction on the Ru/CeO2 catalysts promoting the formation of small (~3 nm) Ru particles. Addition of sodium as a promoter leads to the formation of smaller Ru particle sizes in addition to the modification of the electronic environment of Ru, enhancing the ammonia decomposition activity at low temperatures. This effect is particularly noticeable in the Ru-Na/CNT catalysts, facilitated by the high conductivity of the support, allowing distant electronic modification of the Ru active sites. This work provides novel insights in designing catalysts for hydrogen production from ammonia in our effort to enable the long-term energy storage in chemical bonds.