Research on Chemical Intermediates ( IF 2.8 ) Pub Date : 2021-11-05 , DOI: 10.1007/s11164-021-04614-4 Dong Ho Kim 1, 2 , Yeon Jae Park 1, 2 , Heon Phil Ha 1 , Dong Wook Kwon 1 , Kwan-Young Lee 2
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The role of SiO2 and WO3 in CeVO4-based catalyst supported on TiO2 support containing silica-tungsten was systematically investigated for selective catalytic reduction (SCR) by hydrothermal aging. It has been found that the CeVO4 with SiO2 and WO3 added to TiO2 (i.e., CeVO4/TWS) is the optimal catalyst to promote N2 selectivity through improved thermal stability and NH3 oxidation. CeVO4/TWS(HT; hydrothermal aging) had abundant defects and surface adsorbed oxygen species even after thermal aging. The high Vn+ (n = 4, 3) fraction of CeVO4/TWS(HT) is due to the improved thermal stability by adding SiO2 and WO3 to TiO2. The addition of SiO2 and WO3 maintains NH3 adsorption and redox properties, so the TWS support exhibits high thermal stability. As the NH3-SCR reaction mechanism, the pristine catalyst shows an Eley–Rideal and Langmuir–Hinshelwood models as dual model (ER-LH) based on abundant Lewis and Brønsted acid sites below 300 °C. On the other hand, the hydrothermal aged catalyst dominates the Eley–Rideal mechanism (reaction of activated ammonia with gaseous NO) based on Lewis acid sites. This study comprehensively shows that CeVO4-based catalysts have improved thermal stability by including SiO2 and WO3 in the TiO2 support.
Graphic abstract
中文翻译：
CeVO4 基催化剂的热稳定性取决于氨选择性催化还原 NOx 的载体组成
系统研究了SiO 2和WO 3在CeVO 4基催化剂中的作用，该催化剂负载在含有二氧化硅-钨的TiO 2载体上，用于通过水热老化进行选择性催化还原（SCR）。已经发现的是，CEVO 4用的SiO 2和WO 3加入的TiO 2（即，CEVO 4 / TWS）是促进n中的最佳催化剂2通过改进的热稳定性和选择性NH 3氧化。CeVO 4 /TWS(HT;水热老化)即使在热老化后仍具有丰富的缺陷和表面吸附的氧物种。高 V n+ ( n = 4, 3) CeVO 4 /TWS(HT ) 的分数是由于通过将 SiO 2和 WO 3添加到 TiO 2来改善热稳定性。SiO 2和WO 3 的加入保持了NH 3吸附和氧化还原性能，因此TWS 载体表现出高热稳定性。由于 NH 3-SCR 反应机制，原始催化剂显示 Eley-Rideal 和 Langmuir-Hinshelwood 模型作为双模型 (ER-LH)，基于 300 °C 以下的丰富的路易斯和布朗斯台德酸位点。另一方面，水热老化催化剂主导基于路易斯酸位点的 Eley-Rideal 机制（活性氨与气态 NO 的反应）。该研究综合表明，通过在TiO 2载体中包含SiO 2和WO 3，CeVO 4基催化剂具有改进的热稳定性。
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