Effect of Different Morphologies Induced by Solvent on ZIF-67 Derived Co@NC for Catalytic Phenol Hydrogenation

溶剂诱导法制备不同形貌ZIF-67衍生Co@NC催化剂对苯酚加氢活性的影响

The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excellent phenol hydrogenation activity(conversion 96.9%)at 160℃,3 MPa,which is higher than that of leaf shaped Co@NC-67L-450 catalyst(conversion 75.4%).We demonstrated Co_(3)O_(4)was reduced to the Co^(0)during the reaction.Moreover,CoNx species contribute to the superior hydrogenation activity of phenol.The Co-based catalysts can be easily recovered through the magnetic separation and performed the high stability.

通过溶剂控制生长和氩气气氛热解两步法制备了不同形貌的Co@NC催化剂,得到了具有多面体形貌的Co@NC-67P-450和具有叶片状的Co@NC-67L-450.以苯酚加氢为研究对象评价了两个催化剂的性能,在160℃,3 MPa的条件下,环己醇的选择性均在99.9%以上,Co@NC-67P-450催化剂的苯酚转化率为96.9%,高于Co@NC-67L-450催化剂的75.4%.在反应过程中,Co_(3)O_(4)被还原为Co^(0),Co@NC-67P-450的CoNx含量为47.2%,高于Co@NC-67L-450(33.4%),这些共同促进了其苯酚加氢活性.同时以氨合成为探针反应,研究了CoN_(x)对N_(2)和H_(2)的催化活性,进一步证实了其对苯酚加氢活性的促进作用.通过磁分离可以回收钴基催化剂,并表现出较高的稳定性.