Effect of chromium oxide as active site over TiO2-PILC for selective catalytic oxidation of NO.
Effect of chromium oxide as active site over TiO2-PILC for selective catalytic oxidation of NO.
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DOI：
10.1016/s1001-0742(12)60335-0
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发表时间：
2013-12
影响因子：
6.9
通讯作者：
Jingxin Zhang;Shule Zhang;Wei Cai;Q. Zhong
中科院分区：
文献类型：
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作者：
Jingxin Zhang;Shule Zhang;Wei Cai;Q. Zhong
本研究将TiO 2柱撑粘土（TiO 2-PILC）作为载体催化氧化NO，并分析了氧化铬作为催化氧化过程的活性中心的性能。采用湿浸渍法制备了Cr基催化剂。据发现，10重量%载体上的铬掺杂实现了最好的催化活性。在350°C下，在GHSV = 23600 hr-1的条件下，NO转化率为61%。BET测试结果表明，该载体具有介孔结构。H2-TPR表明，Cr（10）TiP（10 wt.% Cr掺杂的TiO 2-PILC）清楚地显示出平滑的单峰。EPR和XPS被用来解释氧化过程。在NO + O2吸附过程中，超氧阴离子（O2−）释放强度增加。催化剂表面Cr ~（3+）的含量为40.37%，但当催化剂继续吸附NO时，Cr ~（3+）的含量增加到50.28%。此外，Oα/Oβ比值在氧化过程中显著增加。加入SO2后，NO转化率降低，但去除SO2后，催化剂活性基本恢复到初始水平。FT-IR光谱没有显示出明显的SO 42 −特征峰。
This study introduced TiO2-pillared clays (TiO2-PILC) as a support for the catalytic oxidation of NO and analyzed the performance of chromium oxides as the active site of the oxidation process. Cr-based catalysts were prepared by a wet impregnation method. It was found that the 10 wt.% chromium doping on the support achieved the best catalytic activity. At 350°C, the NO conversion was 61% under conditions of GHSV = 23600 hr−1. The BET data showed that the support particles had a mesoporous structure. H2-TPR showed that Cr(10)TiP (10 wt.% Cr doping on TiO2-PILC) clearly exhibited a smooth single peak. EPR and XPS were used to elucidate the oxidation process. During the NO + O2adsorption, the intensity of evolution of superoxide ions (O2−) increased. The content of Cr3+on the surface of the used catalyst was 40.37%, but when the used catalyst continued adsorbing NO, the Cr3+increased to 50.28%. Additionally, Oα/Oβincreased markedly through the oxidation process. The NO conversion decreased when SO2was added into the system, but when the SO2was removed, the catalytic activity recovered almost up to the initial level. FT-IR spectra did not show a distinct characteristic peak of SO42−.