Synthesis and characterization of alpha and beta cobalt hydroxide nanostructures for photocatalytic dye degradation and supercapacitor applications

Alpha and beta cobalt hydroxide nanostructures were synthesized by hydrothermal method and characterized using X-ray diffraction and electron microscopy. The turbostatic alpha-Co(OH)2 has large interlayer spacing compared to the beta-Co(OH)2 and is less explored in the literature. Both nanostructures were efficient in degrading methylene blue dye in the presence of visible light. Under identical conditions, the rate constant of photocatalytic dye degradation in the presence of alpha and beta cobalt hydroxide was calculated as 60.22 × 10−3 min−1 and 19.05 × 10−3 min−1, respectively, which is highest when compared to the previous reports. The superior activity of alpha-Co(OH)2 when compared to beta-Co(OH)2 is also demonstrated in this work. Additionally, a Csp value of 137 F/g and 2.4 F/g, respectively, at a current density of 1 A/g, was obtained from the GCD analysis of devices made using alpha-Co(OH)2 and beta-Co(OH)2. A higher cyclic stability and power density were observed for alpha-Co(OH)2 when compared to beta-Co(OH)2. The findings suggest that alpha and beta cobalt hydroxide nanostructures hold promise as effective catalysts for dye degradation and potential materials for high-performance supercapacitors. Further investigations into the unique properties of the relatively superior alpha-Co(OH)2 could lead to advancements in environmental remediation and energy storage technologies.