Enhancement of ethylbenzene dehydrogenation of perovskite-type BaZrO3 catalyst by a small amount of Fe substitution in the B-site
Enhancement of ethylbenzene dehydrogenation of perovskite-type BaZrO3 catalyst by a small amount of Fe substitution in the B-site
复制标题
B位少量Fe取代增强钙钛矿型BaZrO3催化剂乙苯脱氢
DOI：
10.1016/j.molcata.2015.04.010
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Choji Fukuhara
中科院分区：
文献类型：
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作者：
Ryo Watanabe;Yoshinori Saito;Choji Fukuhara
本研究的目的是澄清的过渡金属（Mn，Fe，Co）取代的BaZrO 3催化剂上的水蒸气脱氢（EBDH）的性能的影响。BaZrO 3催化剂在无水蒸汽条件下表现出较高的EBDH活性，但水蒸汽的加入使EBDH活性显著降低。通过用Mn或Fe部分取代BaZrO 3催化剂中的Zr位，脱氢活性得到显著提高，而Co取代的催化剂表现出明显的低活性。特别地，从2%至4%的小百分比的Fe取代对于用蒸汽的EBDH性能的急剧增强是有效的。比较BaFe_（0.02）Zr_（0.98）O_3催化剂和工业用钾助催化氧化铁（Fe-K）催化剂的苯乙烯产率，发现BaFe_（0.02）Zr_（0.98）O_3催化剂的苯乙烯产率高于Fe-K催化剂。通过ESR测试发现，Fe取代的BZO催化剂经水蒸气EBDH后，其结构中出现了缺陷偶极（Fe ~（3+）-Vox）。高活性BaFe_（0.02）Zr_（0.98）O_3催化剂中存在大量的缺陷偶极，氧迁移率增加。另一方面，低活性催化剂虽然有大量的缺陷偶极子，但在缺陷偶极子环境中的不均匀性增加。这种差异可能导致EBDH与蒸汽的氧化还原性质和性能。在钙钛矿催化剂领域中首次报道了少量Fe取代对氧缺陷周围活性和环境的剧烈变化。
The purpose of this study was to clarify the effect of a transition metal (Mn, Fe, Co) substitution in the BaZrO3catalyst on the performance of ethylbenzene dehydrogenation (EBDH) with steam. The BaZrO3catalyst showed a high performance for the EBDH without steam, however the co-feeding of steam produced a significant decrease in the EBDH activity. By partially substituting the Zr site in the BaZrO3catalyst with Mn or Fe, the dehydrogenation activity was dramatically improved, while the Co-substituted catalyst showed a significantly low activity. In particular, the Fe substitution of a small percentage from 2 to 4% was effective for the drastic enhancement of the EBDH performance with steam. Comparing the styrene yield over the BaFe0.02Zr0.98O3catalyst with that over the industrial potassium-promoted iron oxide (Fe–K) catalyst, the BaFe0.02Zr0.98O3catalyst produced a higher styrene yield than the Fe–K catalyst. From the ESR measurement, we found that the Fe-substituted BZO catalyst had the defect–dipole (Fe3+–Vox) in its structure after EBDH with steam. Highly-active BaFe0.02Zr0.98O3catalyst had a large amount of the defect–dipole and therefore an increase of the oxygen mobility. On the other hand, although low-active catalyst had a large amount of the defect–dipole, but the non-uniformity in the environment of the defect–dipole was increased. Such differences might cause a redox property and a performance for EBDH with steam. The drastic change in activity and environment around the oxygen defect by a small amount of Fe substitution is reported for the first time in the field of perovskite catalysts.