Nb_2O_5对丙烷氧化脱氢催化剂YVO_4的助催化作用

制备了纯相的ＹＶＯ４催化剂，并用浸渍法和机械混合法制备了以Ｎｂ２Ｏ５为助剂的Ｎｂ２Ｏ５／ＹＶＯ４催化剂。催化剂的活性评价结果表明，采用浸渍法制备的Ｎｂ２Ｏ５／ＹＶＯ４催化剂的选择性明显比ＹＶＯ４催化剂高。但ＴＰＲ结果表明，Ｎｂ２Ｏ５／ＹＶＯ４催化剂更难还原。这可归结为Ｎｂ２Ｏ５与ＹＶＯ４的相互作用抑制了氧化能力强的活性位，从而提高了催化剂的选择性。机械混合法制备的催化剂则与ＹＶＯ４相近。

Promoting effect of Nb2O5 on a YVO4 catalystfor oxidative dehydrogenation of propane

The pure phase of YVO 4 is obtained and Nb 2O 5 promoted YVO 4 catalysts are prepared by impregnation and mechanical mixing.The result of activity evaluation indicates that the Nb 2O 5/YVO 4 catalyst prepared by impregnation gives higher selectivity than YVO 4 in oxidative dehydrogenation of propane.The TPR test shows that the Nb 2O 5 promoted YVO 4 catalyst is more difficult to be reduced than YVO 4. This is because the strong oxidation sites of YVO 4 are restrained by Nb 2O 5 so that deep oxidation of the product is avoided,and thus the selectivity to prepene is increased.The Nb 2O 5/YVO 4 catalyst prepared by mechanical mixing is similar to YVO 4.