Efficient charge separation in mixed phase Cu7S4-CuO thin film: Enhanced photocatalytic reduction of aqueous Ni (II) under visible-light

Heterogeneous photocatalysis has attracted great attention for environmental remediation applications because of their efficiency in separating photogenerated electron-hole pair. In view of that, we developed a unique binary heterostructure based photocatalyst consisting of Cu7S4-CuO. Cu7S4 thin films were successfully synthesized using a simple two electrode galvanic deposition method, followed by annealing the films at different temperatures in air to form Cu7S4-CuO and CuO films. Depending on the annealing temperature, partial or complete oxidation of Cu7S4 to CuO takes place. The composition, optical property, morphology and photocatalytic properties of these films were studied. Photoreduction of the toxic Ni (II) was studied under visible light irradiation. The unique binary heterostructure exhibited enhanced photocatalytic property. The basis of enhanced photocatalytic activity is due to the efficient charge separation of photogenerated electron-hole pairs through the heterostructure.