Synthesis and Comparative Evaluation of Optical and Electrochemical Properties of Efficacious Heterostructured-Nanocatalysts of ZnSe with Commercial and Reduced Titania

ABSTRACT We report semiconductor-semiconductor (S-S) type heterostructures prepared by solvothermal method using ZnSe (Z), commercial titania (C-TiO2) and reduced titania (R-TiO2-x) as precursor materials. The synthesized Z-C-TiO2 and Z-R-TiO2-x heterostructures manifest remarkable electrocatalytic oxygen evolution reaction (OER) activity with onset over potential of only 320 mV (Tafel slope = 40 mV dec-1) and 325 mV (Tafel slope = 45 mV dec-1) respectively, with activity over 6 h of testing time in alkaline medium. This enhancement in the activities of engineered nanoscale materials can be attributed to the better coping of reaction intermediate through synergistic effect of two semiconducting materials. Owning to the reduced electron-hole recombination by versatile cascade band alignment of titania with ZnSe, these heterostructures also show superior photocatalytic activity for degradation of reactive blue-866 dye (RB-866) under visible light irradiation when compared to pure titania.