The photoelectrochemistry of the hetero-junction Ag/NiFe₂O₄, elaborated by sol gel route, was successfully used for the nitrite oxidation under visible light illumination. The electrons of NiFe₂O₄ activated by visible light are transferred toward Ag particles, strongly contacted to NiFe₂O₄. The hetero-junction is generated by incorporating ultrafine Ag clusters, thereby precluding high over-voltages. The spinel was studied by thermal analysis, X-ray diffraction and scanning electron microscopy. The optical band gap of NiFe₂O₄ (1.63 eV) is assigned to the lifting of degeneracy of the Fe³⁺: 3d orbital by oxygen crystal field splitting in octahedral site. p-type conduction of NiFe₂O₄ was shown from the (capacitance⁻² – potential)characteristic in KOH electrolyte (0.1 M). The valence band (+0.70 V) is more anodic than the potential of NO₂⁻ oxidation and the hetero-junction was successfully tested for the conversion of NO₂⁻ to NO₃⁻ under visible light irradiation. NO₂⁻ is a hazardous ion and the photocatalytic performance is due to the optimal band bending. The rate conversion {0.085 μmol NO₂⁻(g catalyst)⁻¹ mn⁻¹} was quantified indirectly through the evolved H₂ volume.

通过溶胶-凝胶法制备的异质结Ag / NiFe ₂ O ₄的光电化学已成功用于可见光照射下的亚硝酸盐氧化。可见光激活的NiFe ₂ O ₄电子被转移到Ag颗粒上，并与NiFe ₂ O ₄牢固接触。异质结是通过掺入超细Ag团簇而产生的，从而避免了高过电压。通过热分析，X射线衍射和扫描电子显微镜研究了尖晶石。NiFe ₂ O ₄的光学带隙（1.63 eV）与提升Fe ³⁺的简并性有关：3d轨道由氧晶体在八面体部位分裂。p由NiFe型传导₂ ö ₄（电容从所示^-2在KOH电解质（0.1M） -电位）特性。价带（0.70 V）比NO的电位更阳极₂ ^-氧化和异质结被成功地测试了NO转化₂ ^-为NO ₃ ^-可见光照射下。NO ₂ ^-是一种有害离子和光催化性能是由于最佳带弯曲。速率变换{0.085微摩尔NO ₂ ^- （克催化剂^{） -1}mn ^-1 }通过析出的H ₂体积间接定量。