Investigation of ZnSe/ZnO nanocomposite constructed as an electro-catalyst and photo-catalyst for enhanced supercapacitor and photo catalytic dye degradation application.

Abstract

Energy crisis and depleting energy resources have triggered into plentiful efforts for the development alternative ways to cope up with the energy deficiency. Supercapacitor is one such energy storage device that plays an essential role in constant energy supply. Transitional metal selenides and their composites have undergone research in the recent times as potential candidates of supercapacitor devices due to their astounding physical, chemical and electrical properties. Selenium possesses an electronegativity lower than that of oxides and sulfur. This makes the chemical bond between the atom and the binding electrons weaker resulting in higher electrochemical activity that metal oxides or hydroxides. A ZnSe/ZnO composite has been synthesized by a facile hydrothermal method and investigated as a potential supercapacitor electrode in this work. The phase purity and morphology of the synthesized materials were examined through basic characterization techniques such as XRD, FESEM, FTIR etc. The composite material ZnSe/ZnO delivered high specific capacitance that is 155 at 0.3A/g in the charge-discharge profile and stable long cycle life retaining 95.5% over 3000 cycles. It also shows high specific capacitance that is 126.95 in 5mV/s. Moreover, the composite structure ZnSe/ZnO enhances electrochemical performance by offering additional electrolyte ions and electron mobility. Therefore ZnSe/ZnO composite can be utilized as a promising candidate for supercapacitor applications. The ZnO/ZnSe heterostructures showed significantly increased deep-level emission together with a comparatively decreased UV emission at ambient temperature. Furthermore, the heterostructure demonstrated impressive photo-catalytic abilities by degradation of organic azo dyes which are harmful for the environment and thereby helping in water purification.