The Effect of SO2 and H2O on the Interaction Between Pt and TiO2(P-25) During Catalytic CO Oxidation
The Effect of SO2 and H2O on the Interaction Between Pt and TiO2(P-25) During Catalytic CO Oxidation
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DOI：
10.1007/s10562-019-02672-3
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发表时间：
2019-04-01
影响因子：
2.8
通讯作者：
Einaga, Hisahiro
中科院分区：
文献类型：
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作者：
Taira, Kenji;Einaga, Hisahiro
贵金属催化剂被SO2和H2O失活是钢铁工业中烧结过程产生的烟气的后燃烧处理中的常见问题。为了开发耐SO2的CO氧化催化剂，本文采用X射线光电子能谱（XPS）、透射电子显微镜（TEM）和漫反射红外傅里叶变换（DRIFT）光谱研究了SO2和H2O对Pt/TiO 2（P-25）催化剂CO氧化活性的影响。Pt/TiO 2（P-25）催化剂在无SO2和有H2O存在时，CO氧化活性和稳定性提高，而在SO2存在时，CO氧化活性和稳定性受到很大程度的抑制和不可逆失活。XPS和TEM结果表明，Pt颗粒尺寸和氧化态的变化不是导致失活的主要原因。相反，根据DRIFT光谱，CO和H2O之间的相互作用在金属-载体界面后，在SO2的存在下，在TiO 2表面上的TiO SO 4的形成被削弱。这导致了先前观察到的增强CO氧化在潮湿条件下的损失。这些结果表明，在SO2存在下，TiOSO 4的形成是不可逆失活的主要原因。因此，从TiO 2表面去除TiOSO 4层是催化剂再生的关键步骤。
The deactivation of noble metal catalysts by SO2 and H2O is a common issue in the post combustion treatment of flue gases from sintering processes in the steel industry. In an effort to develop SO2-tolerant CO-oxidation catalysts, herein, we investigated the effect of SO2 and H2O on the catalytic activity of Pt/TiO2(P-25) catalysts for CO oxidation using X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and diffuse-reflectance infrared Fourier-transform (DRIFT) spectroscopy. Pt/TiO2(P-25) catalysts, in the absence of SO2 and presence of H2O, enhanced the activity and stability of CO oxidation, while being largely suppressed and irreversibly deactivated in the presences of SO2. The XPS and TEM results suggested that variations in the Pt particle size and oxidation state were not major causes of the deactivation. Instead, according to DRIFT spectra, the interaction between CO and H2O at the metal-support interface was weakened after the formation of TiOSO4 on the TiO2 surface in the presence of SO2. This resulted in a loss of the previously observed enhancement of CO oxidation under humid conditions. These results indicate that in the presence of SO2, the formation of TiOSO4 is the major cause of irreversible deactivation. Therefore, removal of the TiOSO4 layer from the TiO2 surface is a crucial step for catalyst regeneration.