Performance, Structure and Mechanism of ReOx-Pd/CeO2 Catalyst for Simultaneous Removal of Vicinal OH Groups with H2
Performance, Structure and Mechanism of ReOx-Pd/CeO2 Catalyst for Simultaneous Removal of Vicinal OH Groups with H2
复制标题
H2同时脱除邻位羟基的ReOx-Pd/CeO2催化剂的性能、结构及机理
DOI：
10.1021/acscatal.6b00491
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发表时间：
2016
期刊：
影响因子：
12.9
通讯作者：
Keiichi Tomishige
中科院分区：
文献类型：
--
作者：
Nobuhiko Ota;Masazumi Tamura;Yoshinao Nakagawa;Kazu Okumura;Keiichi Tomishige
Pd改性的CeO 2负载Pd催化剂（ReOx-Pd/CeO 2（Re = 2wt%，Pd/Re = 0.25））仍然是最好的同时加氢脱氧催化剂。较高的Re负载量降低了活性。环状邻二醇的同时加氢脱氧具有高顺式立体选择性。采用XRD、TEM、H2-TPR、XAFS、XPS、拉曼和DFT等方法对ReOx-Pd/CeO 2催化剂进行了表征。ReOx-Pd/CeO_2（Re = 2wt%，Pd/Re = 0.25）催化剂上的Re物种经还原和1，2-己二醇合成1-己烯的化学计量反应后分别为ReIV和ReVI，ReIV物种经化学计量反应转化为ReVI物种。ReOx-Pd/CeO 2上的Re物种被认为随机分布在CeO 2表面，并且可能只有单体Re物种具有同时加氢脱氧的催化活性。该模型可以解释Re = 2wt%的催化剂比高Re负载量的催化剂具有更高的活性。该反应被建议进行的四/六价氧化还原循环的Re中心的催化，然后氢化。
The ceria-supported rhenium catalyst modified with palladium (ReOx–Pd/CeO2(Re = 2 wt %, Pd/Re = 0.25)) is still the best catalyst for simultaneous hydrodeoxygenation. Higher Re loading amount decreased the activity. The simultaneous hydrodeoxygenation of cyclic vicinal diols occurs with highcis-stereoselectivity. ReOx–Pd/CeO2catalysts were characterized by means of XRD, TEM, H2-TPR, XAFS, XPS, Raman, and DFT calculations. The Re species on ReOx–Pd/CeO2(Re = 2 wt %, Pd/Re = 0.25) catalyst after reduction and after stoichiometric reaction of 1,2-hexanediol to 1-hexene were ReIVand ReVI, and the ReIVspecies were converted to ReVIthrough the stoichiometric reaction. The Re species on ReOx–Pd/CeO2are proposed to be randomly located on the CeO2surface, and probably only monomeric Re species have catalytic activity for simultaneous hydrodeoxygenation. This model can explain the higher activity of Re = 2 wt % catalyst than those of higher Re loading catalysts. The reaction is proposed to proceed by the tetra/hexavalent redox cycle of the Re center in the catalysis followed by hydrogenation.