Spectroscopic characterization and photo catalytic degradation ability of ternary oxides of Cobalt

Abstract

In the present work we have prepared and characterized the two ternary forms of cobalt titanate namely ilmenite and cubic by the sol-gel technique simply by replacing the titanium precursor and using a cationic surfactant micelle solution followed by calcinations at 600°C and 800°C respectively. In both cases, the nanopowders revealed a dark bluish green color, different morphologies of spherical, rhombus and needle shapes with mean particle sizes 29 and 37 nm, respectively. Bearing growing environmental concerns in mind, we have also highlighted a simple nano chemistry based clean and efficient process for effective degradation of hazardous malachite green oxalate dye by an in-situ ultraviolet irradiation set-up. In this field there is hardly any report involving comparative study of ternary oxides of cobalt as potential candidates for photo catalytic degradation. We ultimately observed that cobalt meta titanate proved itself the optimal catalyst at a calcination temperature of 600°C showing a maximum degradation efficiency of 96.38% It also showed a better first-order rate constant of 0.01636 min-1. A decent attempt to correlate photoluminescence and photo catalysis has also been made. Also, a heterojunction has been fabricated with cobalt meta titanate and the parameters of crucial importance in photocatalysis namely conductivity, carrier mobility, transit time evaluated from the current-voltage characteristics.