Control synthesis of CeO 2 nanomaterials supported gold for catalytic oxidation of carbon monoxide
Control synthesis of CeO 2 nanomaterials supported gold for catalytic oxidation of carbon monoxide
复制标题
控制合成CeO 2 纳米材料负载金催化氧化一氧化碳
DOI：
10.1016/j.mcat.2017.09.024
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发表时间：
2017
影响因子：
4.6
通讯作者：
Gang Feng
中科院分区：
文献类型：
--
作者：
Rongbin Zhang;Kun Lu;Lijuan Zong;Sai Tong;Gang Feng
CeO 2具有氧空位、储氧能力强、Ce 3+和Ce 4+易转化等特点，在催化剂中表现出优异的性能。采用水热法制备了不同形貌的氧化铈纳米材料。发现通过初湿含浸法制备的二氧化铈上的金颗粒比通过沉积-沉淀法制备的那些更小且更均匀（Applied Surface Science 2017，416，183-190）。采用等体积浸渍法制备的样品对CO氧化的催化性能也优于沉积-沉淀法制备的样品。表征结果表明，金纳米颗粒的小尺寸以及氧化态有助于比沉积沉淀样品更高的活性。在70 ℃时，0.5% Au/CeO 2 NT的CO转化率可达10 0%，比0.5% Au/CeO 2棒和0.5% Au/CeO 2 NC的活性和稳定性好得多。XPS结果表明，这是由于较高的Ce 3+ /Ce 4+和Au？0.5%Au/CeO 2 NT的Au/Au 0比0.5%Au/CeO 2 NT棒和0.5%Au/CeO 2 NC的Au/Au 0高，这是因为存在特定的Au？+ -Ce 3+结构促进了分子氧的吸附，进一步有利于CO的氧化。此外，金纳米颗粒可以在氧化铈纳米立方体上生长成更大的颗粒，导致催化剂失活。相比之下，二氧化铈纳米棒和纳米管负载的催化剂显示出优异的稳定性。
CeO 2 show excellent performance in catalysis due to its oxygen vacancies, high oxygen storage capacity and easy conversation between Ce 3+ and Ce 4+ oxidation states. The ceria nano-materials with different morphologies were prepared with hydrothermal methods in the present work. It is found that the gold particles on ceria prepared via incipient wetness impregnation method are smaller and more uniform than those prepared via deposition-precipitation method (Applied Surface Science 2017, 416, 183–190). The incipient wetness impregnation method prepared samples also show better catalytic performance for CO oxidation than the samples prepared via deposition-precipitation method. Characterization results reveal that the small sizes as well as the oxidation states of the gold nanoparticles contribute to the higher activity than the deposition-precipitation samples. For the incipient wetness impregnation samples, the 0.5%Au/CeO 2 NT could reach 100% CO conversion at 70 ◦ C, which shows much better activity and stability than the 0.5%Au/CeO 2 rod and 0.5%Au/CeO 2 NC. XPS results indicates that this is because the higher Ce 3+ /Ce 4+ and Au ?+ /Au 0 of 0.5%Au/CeO 2 NT than 0.5%Au/CeO 2 rod and 0.5%Au/CeO 2 NC, since the presence.of a specific Au ?+ -Ce 3+ structure promotes the adsorption of molecular oxygen and further favors the oxidation of CO. In addition, the gold nanoparticle could grow into larger particles on the ceria nanocubes and leads to the deactivition of the catalysts. In contrast the ceria nanorod and nanotube supported catalysts show excellent stability.