Effect of rare earth elements（La,Y,Pr）in multi-element composite perovskite oxide supports for ammonia synthesis
来源期刊：JOURNAL OF RARE EARTHS2021年第4期
论文作者：Wei Li Shuang Wang Jinping Li
摘 要：A series of BaCeO3 modified with different rare earth elements（La,Y,Pr） were synthesized by coprecipitation and calcination and the effect of rare earth elements for catalytic ammonia synthesis under mild conditions was studied.The ammonia synthesis performance tests show that 2.5% Ru/BaCe0.9La0.1O3-δ catalyst（All the percentages of Ru in this article are in mass fraction） exhibits the highest ammonia synthesis rate（34 mmol/（g·h）） at 3 MPa,450℃,and no sign of deactivation after 100 h of reaction.H2-TPR and XPS analyses indicate that the introduction of La increases the amount of oxygen vacancies of the catalyst,which is beneficial to increasing the electron density of Ru surface.HRTEM analysis shows that the Ru particle size is reduced greatly after La is introduced,which facilitates the catalyst generating more Bs-type sites（active sites of Ru species for N≡N dissociation）.CO2-TPD analysis indicates that BaCe0.9La0.1O3-δ has stronger basicity,which promotes electrons transfer from support to Ru.This work provides an effective method for design and synthesis of Ru-based multi-element composite perovskite oxide catalysts.
Wei Li1，Shuang Wang1,2，Jinping Li1
1. Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization,College of Chemistry and Chemical Engineering,Taiyuan University of Technology2. College of Environmental Science and Engineering,Taiyuan University of Technology
摘 要：A series of BaCeO3 modified with different rare earth elements（La,Y,Pr） were synthesized by coprecipitation and calcination and the effect of rare earth elements for catalytic ammonia synthesis under mild conditions was studied.The ammonia synthesis performance tests show that 2.5% Ru/BaCe0.9La0.1O3-δ catalyst（All the percentages of Ru in this article are in mass fraction） exhibits the highest ammonia synthesis rate（34 mmol/（g·h）） at 3 MPa,450℃,and no sign of deactivation after 100 h of reaction.H2-TPR and XPS analyses indicate that the introduction of La increases the amount of oxygen vacancies of the catalyst,which is beneficial to increasing the electron density of Ru surface.HRTEM analysis shows that the Ru particle size is reduced greatly after La is introduced,which facilitates the catalyst generating more Bs-type sites（active sites of Ru species for N≡N dissociation）.CO2-TPD analysis indicates that BaCe0.9La0.1O3-δ has stronger basicity,which promotes electrons transfer from support to Ru.This work provides an effective method for design and synthesis of Ru-based multi-element composite perovskite oxide catalysts.
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