Electronic metal-support interaction enhanced ammonia decomposition efficiency of perovskite oxide supported ruthenium

Abstract

The performance of Ru/La 1-x Sr x AlO 3 catalyst in ammonia decomposition was enhanced by modulating its electronic properties via the strategy of cation substitution. • We present an effective strategy of cation substitution to modulate electronic properties of Ru/La 1-x Sr x AlO 3 catalysts. • Electron-rich Ru facilitates associative desorption of N atoms and accelerates the ammonia decomposition reaction. • Ru/La 0.8 Sr 0.2 AlO 3 catalyst shows high catalytic efficiency and excellent stability during a test perid of 70 h. Ammonia has been considered as a promising hydrogen carrier with high energy storage density and easy transport. Here, we report the ruthenium (Ru) nanoparticles supported on LaAlO 3 , a typical ABO 3 perovskite oxide, as an efficient catalyst for ammonia decomposition. By tailoring the cation substitution of La 3+ by Sr 2+ , the electronic properties of support materials were modulated, which exerts an impact on the electronic state of Ru active sites. It is found that the Ru/La 0.8 Sr 0.2 AlO 3 catalyst has a high hydrogen formation rate and low activation energy. In situ spectroscopic investigation and NH 3 temperature programmed desorption (NH 3 -TPD) analyses indicate the electron-rich state of metallic Ru on the La 0.8 Sr 0.2 AlO 3 support, which promotes associative desorption of N atoms and accelerates NH 3 decomposition reactions. This study provides a universal strategy of aliovalent cation substitution to engineer the electronic properties of metal/oxide catalysts as well as their catalytic activities.