La2Ce2O7 supported ruthenium as a robust catalyst for ammonia synthesis
来源期刊:JOURNAL OF RARE EARTHS2019年第5期
论文作者:Wenfeng Han Zhi Li Huazhang Liu
文章页码:492 - 499
摘 要:La2Ce2O7 nanoparticles were prepared by citric acid complexation method followed by calcination at varied temperatures. Then, supported with 4 wt% Ru, they were evaluated as the catalysts for ammonia synthesis under conditions similar with industry. With La2Ce2O7 being calcinated at 700 or 800℃, the experimental results indicate that the Ru/La2Ce2O7 catalyst exhibits much higher ammonia concentration or ammonia synthesis rate than that of Ru/CeO2 and Ru/La2O3. In addition, Ru/La2Ce2O7 possesses high stability under over-heating test. In the absence of any promotor, ammonia concentration of Ru/La2Ce2O7 catalyst approaches 14% at 450℃, GHSV of 10000 h-1 and pressure of 10 MPa. The rate-determining step of ammonia synthesis, dissociation of N2 is significantly facilitated by the strong metalesupport interaction(SMSI) between Ru and La2Ce2O7. Due to the interaction, La2Ce2O7 tends to donate electrons to Ru,resulting in the high electron density over the surface of Ru active sites which is favorable for the dissociation of N2. Consequently, high activity is achieved.
Wenfeng Han,Zhi Li,Huazhang Liu
Institute of Industrial Catalysis, Zhejiang University of Technology
摘 要:La2Ce2O7 nanoparticles were prepared by citric acid complexation method followed by calcination at varied temperatures. Then, supported with 4 wt% Ru, they were evaluated as the catalysts for ammonia synthesis under conditions similar with industry. With La2Ce2O7 being calcinated at 700 or 800℃, the experimental results indicate that the Ru/La2Ce2O7 catalyst exhibits much higher ammonia concentration or ammonia synthesis rate than that of Ru/CeO2 and Ru/La2O3. In addition, Ru/La2Ce2O7 possesses high stability under over-heating test. In the absence of any promotor, ammonia concentration of Ru/La2Ce2O7 catalyst approaches 14% at 450℃, GHSV of 10000 h-1 and pressure of 10 MPa. The rate-determining step of ammonia synthesis, dissociation of N2 is significantly facilitated by the strong metalesupport interaction(SMSI) between Ru and La2Ce2O7. Due to the interaction, La2Ce2O7 tends to donate electrons to Ru,resulting in the high electron density over the surface of Ru active sites which is favorable for the dissociation of N2. Consequently, high activity is achieved.
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