ZnFe_2O_4中阳离子分布对苯酚H_2O_2羟化制苯二酚催化活性的影响

Influence of Cation Distribution of ZnFe_2O_4 on Its Catalytic Activityof Phenol Hydroxylation with H_2O_2

具有尖晶石结构的铁酸盐是苯酚 H2 O2 羟化合成苯二酚的有效催化剂 .分别用共沉淀和水热法制备了Zn Fe2 O4,并用 Mossbauer,XRD和 ESR等方法予以表征 .发现不同方法制备的 Zn Fe2 O4中阳离子在四面体和八面体位置的分布不同 ,认为阳离子分布影响了催化活性 .

The spinel ferrite exhibits a good catalytic performance in phenol hydroxylation by H 2O 2 to dihydroxybenzene. ZnFe 2O 4 was synthesized by co-precipitation and hydrothermal methods. The catalysts were characterized by means of Mssbauer spectroscopy, XRD and ESR techniques.The results of Mssbauer spectra, XRD and ESR all indicate that ZnFe 2O 4 synthesized from hydrothermal processing is the normal spinel structure, while ZnFe 2O 4 synthesized from co-precipitation method is partly inverse spinel with a substantial displacement of Fe 3+ cations to A sites and Zn 2+ cations into B sites of the cubic close-packed anionic sublattice. We found that the distribution of cations on tetrahedral and octahedral sites in zinc ferrites was different between the catalysts prepared by hydrothermal and co-precipitation methods, and the catalytic activity was influenced by the distribution of cations.