Ni²⁺ was reduced by photo-catalysis on the hetero-system p-CuCo₂O₄ /n-TiO₂ under visible light. The spinel CuCo₂O₄, elaborated by nitrate route, was characterized photo-electrochemically. A direct forbidden band of 1.44 eV was determined from the diffuse reflectance. It exhibits p-type behavior and a conduction band (- 1.11 V_SCE) made up of Co³⁺: e_g orbital, more cathodic than the Ni²⁺ level (-0.68 V_SCE). The rate of Ni deposition increases with increasing the spinel dose and peaks for the optimal ratio CuCO₂O₄/TiO₂ (50/50) with 60 % conversion (30 mg L⁻¹) in less than 3 h. This occurred because TiO₂ mediates the electron transfer to adsorbed Ni²⁺ ions. The decrease of the conversion rate on the system CuCo₂O₄/TiO₂ over illumination time is due to the competitive water reduction onto deposited Ni clusters. The in situ photo-deposition of Ni-clusters forms hetero-system CuCo₂O₄/TiO₂/Ni intimately contacted and the H₂ formation is highly improved because of the low Ni over-potential. H₂-evolution rate of 4.69 μmol min⁻¹ g⁻¹ and a quantum yield of 0.68 % were obtained under a light flux of 2.09 × 10¹⁹ photons s⁻¹.

通过在可见光下在异体系p -CuCo ₂ O ₄ / n -TiO ₂上光催化还原Ni ²⁺。用硝酸盐法对尖晶石CuCo ₂ O ₄进行了光电化学表征。由漫反射确定1.44eV的直接禁带。它表现出p型行为和由Co ³⁺构成的导带（-1.11 V _SCE）：e _g轨道，比Ni ²⁺能级（-0.68 V _SCE）。Ni的沉积速率随尖晶石剂量的增加而增加，并且在不到3小时的时间内，具有60％转化率（30 mg L ^-1）的最佳比例CuCO ₂ O ₄ / TiO ₂（50/50）达到峰值。这是因为TiO ₂介导了电子转移到吸附的Ni ²⁺离子上。CuCo ₂ O ₄ / TiO ₂体系上的转化率随光照时间的降低是由于竞争性减少了沉积在Ni团簇上的水。Ni团簇的原位光沉积形成紧密接触的异质体系CuCo ₂ O ₄ / TiO ₂ / Ni和H由于低的Ni超电势，大大改善了_2的形成。在2.09×10 ^19个光子s ^-1的光通量下，H _2的演化速率为4.69μmolmin ^-1 g ^-1，量子产率为0.68％。