Enhanced oxygen vacancies on yttrium oxide with cobalt oxide loaded for accelerating hydrogen production from ammonia...

Ammonia decomposition for hydrogen production has become a critical process in the development of hydrogen economy. Non-noble based material possesses great potential of application in thermal catalysis due to its low cost and appreciable theoretical catalytic activity. However, the durability of non-noble metal catalysts under prolonged operation remains a significant challenge. Herein, the cobalt oxide supported on yttrium oxide catalysts with enhanced oxygen vacancies via co-precipitation was reported by using urea serving as a pH stabilizer, followed by annealing process in an inert atmosphere. The formation of enhanced oxygen vacancies was demonstrated accelerated the NH bond division and nitrogen recombination-desorption, thereby enhancing the efficiency of thermal catalytic decomposition of ammonia. Based on such advantages, the synthesized 50CoO/Y₂O₃ catalyst exhibited optimal NH₃ decomposition performance, achieving an ammonia conversion rate of 98.6 % under a high gas hourly space velocity of 20,000 mL·g_cat^-1·h^-1 with a hydrogen production rate of 22.3 mmol·g_cat^-1·min^-1 at 550 °C. Moreover, the catalyst maintained a stable activity for 120 h without significantly degradation, suggesting non-noble based catalyst a potential competitor in hydrogen production from thermal catalytic ammonia decomposition.