Highly efficient and stable Ru-doped LaFeO3 based perovskite catalyst for green hydrogen production via ammonia decomposition

Abstract

Recently, ammonia has emerged as a valuable hydrogen carrier material. Previous studies have pioneered to use perovskite catalyst for hydrogen production from ammonia. Following the trend, numerous studies mainly focused on modifying structure and composition of perovskite catalyst due to their desirable properties. In this study, Ru-doped LaFeO₃ perovskite catalysts were investigated to reduce Ru contents and enhance catalytic activity. These catalysts were coated on the alumina pellet to utilize in the process due to protecting back pressure in the reactor and improving performance. The Ru-doped LaFeO₃ based perovskite structure was successfully synthesized with sodium bicarbonate sol-gel method, and 5, 7, and 10 mol% ruthenium was appropriately replaced instead of B-site iron according to main peak shifting on XRD analysis. The 10 mol% Ru-doped (LaFe_0·9Ru_0·1O₃) alumina supported catalyst achieved over 80 % ammonia conversion at 450 °C and maintained an average ammonia conversion rate of over 99 % stably during 145 h at 500 °C. Especially, the Fe_9·45Ru_0.55 bimetallic particles were demonstrated by XRD, XPS and TEM analysis on after-tested catalyst surface, and those are improving catalytic activity gradually. This study provides a promising catalyst for ammonia decomposition utilizing the perovskite structure with lower Ru content compared to the other Ru-based catalysts.