Kinetics of ammonia synthesis over Ru/Pr2O3
Kinetics of ammonia synthesis over Ru/Pr2O3
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DOI：
10.1016/j.jtice.2019.10.006
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发表时间：
2019-12-01
影响因子：
5.7
通讯作者：
Nagaoka, Katsutoshi
中科院分区：
文献类型：
--
作者：
Imamura, Kazuya;Miyahara, Shin-ichiro;Nagaoka, Katsutoshi
我们研究了NH3合成的动力学组成的低结晶Ru纳米层负载在Pr2O3的催化剂。我们确定了在不同温度和压力下Ru/Pr_2O_3、Ru/CeO_2和Ru/MgO催化剂上N-2、H-2和NH_3的反应级数。在所有反应条件下，所有催化剂的反应级数几乎都是1，表明反应的速率控制步骤是N = N键的断裂。与此相反，相对于H-2的反应级数不同的催化剂，并随着压力的增加而降低，并随着温度的升高而增加。在所有条件下，相对于H-2的反应级数是最大的Ru/Pr2O3和最小的Ru/MgO，表明氢中毒的Ru表面被推迟到更大程度上超过Ru/Pr2O3比超过Ru/MgO。与H-2反应级数的趋势一致，当压力从0.1增加到3.0 MPa时，在400 ℃下Ru/Pr2O3上的NH3合成速率急剧上升（64 mmol h（-1）g（-1））。此外，在3.0 MPa下降低进料气体H-2/N-2比率有效地增加了Ru/Pr2O3上的NH3合成速率，在350 ℃下在H-2/N-2比率为1/0.5时达到45 mmol h（-1）g（-1）。(C)2019台湾化学工程师学会Elsevier B.V.出版，保留所有权利。
We investigated the kinetics of NH3 synthesis over a catalyst consisting of low-crystalline Ru nano-layers supported on Pr2O3. We determined the reaction orders with respect to N-2, H-2, and NH3 at various temperatures and pressures over Ru/Pr2O3, as well as Ru/CeO2 and Ru/MgO. The reaction orders with respect to N-2 were always almost unity for all the catalysts under all the reaction conditions, indicating that the rate-determining step was N=N bond cleavage. In contrast, the reaction orders with respect to H-2 differed among the catalysts and decreased with increasing pressure and increased with increasing temperature. Under all conditions, the reaction order with respect to H-2 was largest over Ru/Pr2O3 and smallest over Ru/MgO, indicating that hydrogen poisoning of the Ru surface was retarded to a greater extent over Ru/Pr2O3 than over Ru/MgO. In agreement with the trends of the H-2 reaction orders, the NH3 synthesis rates over Ru/Pr2O3 at 400 degrees C rose drastically (64 mmol h(-1) g(-1)) as the pressure was increased from 0.1 to 3.0 MPa. Furthermore, decreasing the feed gas H-2/N-2 ratio at 3.0 MPa effectively increased the NH3 synthesis rate over Ru/Pr2O3, which reached 45 mmol h(-1) g(-1) at 350 degrees C at a H-2/N-2 ratio of 1/0.5. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.