Oxidation of CH4 over Pd supported on TiO2-doped SiO2: Effect of Ti(IV) loading and influence of SO2
Oxidation of CH4 over Pd supported on TiO2-doped SiO2: Effect of Ti(IV) loading and influence of SO2
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DOI：
10.1016/j.apcatb.2008.10.023
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发表时间：
2009-05
影响因子：
22.1
通讯作者：
A. Venezia;G. Carlo;G. Pantaleo;L. Liotta;Gérôme Melaet;N. Kruse
中科院分区：
文献类型：
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作者：
A. Venezia;G. Carlo;G. Pantaleo;L. Liotta;Gérôme Melaet;N. Kruse
采用溶胶-凝胶法制备了不同重量％TiO2的二氧化钛改性二氧化硅，并将其用作Pd（1wt％）催化剂的载体。在贫乏条件下，在不存在和存在 SO2 的情况下，对所获得的材料进行了甲烷氧化测试。连续进行测试反应以评估热稳定性和中毒可逆性。 TiO2 用量的增加提高了催化活性，TiO2 负载量为 10wt% 时性能最佳。此外，通过将二氧化钛添加到反应物中或在 350°C 下将其作为纯预处理气氛进料，含二氧化钛催化剂表现出对 SO2 的优异耐受性。通过 XPS、XRD、FT-IR 和 BET 测量对催化剂进行表征。根据结构和表面分析，混合氧化物含有 Si-O-Ti 连接，这被解释为导致负载 PdO 相对于纯 SiO2 或纯 TiO2 上的 PdO 的本征活性增强。此外，硫分子与TiO2的优先相互作用以及高表面积二氧化硅易于脱附SOx是TiO2掺杂催化剂具有优异的SO2耐受性的决定因素。
Titania-modified silicas with different weight% of TiO2were prepared by sol–gel method and used as supports for Pd (1wt%) catalysts. The obtained materials were tested in the oxidation of methane under lean conditions in absence and in presence of SO2. Test reactions were consecutively performed in order to evaluate the thermal stability and poisoning reversibility. Increasing amounts of TiO2improved the catalytic activity, with an optimum of the performance for 10wt% TiO2loading. Moreover, the titania-containing catalysts exhibited a superior tolerance towards SO2by either adding it to the reactants or feeding it as a pure pretreatment atmosphere at 350°C. Catalysts were characterized by XPS, XRD, FT-IR and BET measurements. According to the structural and surface analyses, the mixed oxides contained Si–O–Ti linkages which were interpreted as being responsible for the enhanced intrinsic activity of supported PdO with respect to PdO on either pure SiO2or pure TiO2. Moreover, the preferential interaction of the sulfur molecule with TiO2and the easy SOxdesorption from high surface area silica were the determining factors for the superior SO2tolerance of the TiO2-doped catalysts.