Hydrothermally synthesized cobalt vanadate nanoparticles for photocatalytic degradation of Fast Orange Red dye and supercapacitor applications

Herein, Co2V2O7 and Co3V2O8 nanoparticles (NPs) were synthesized by changing only the precursor molar ratio using a simple hydrothermal approach. Numerous analytical approaches were used to characterise the synthesized NPs. The crystal structures of the NPs were found to be monoclinic (Co2V2O7) and orthorhombic (Co3V2O8) with an average crystallite size of 29 nm and 25 nm, respectively. Furthermore, the band gaps for Co2V2O7 and Co3V2O8 were calculated to be 1.8 eV and 2.1 eV, respectively. The supercapacitor properties of both the synthesized NPs were performed. After 1000 cycles, the specific capacitance values were determined to be 628 F center dot g(-1) for Co2V2O7 nanoparticles and 415 F center dot g(-1) for Co3V2O8, indicating an excellent retention rate of almost 90 % for both materials. Furthermore, stability measurements at a current density of 5 A center dot g(-1) demonstrated that even after 3000 cycles, the capacitive retention remained stable at 90 %. The photocatalytic investigations for the degradation of Fast Orange Red dye using Co2V2O7 and Co3V2O8 was performed. Co2V2O7 showed a decolourization rate of 93.8 %, whereas Co3V2O8 had a decolourization rate of 88.95 % within 120 min of UV light irradiation. Overall, the research sheds light on the properties of Co2V2O7 and Co3V2O8 nanoparticles, making them viable candidates for practical energy and environmental applications. The obtained results also motivate the synthesis of comparable NPs with improved characteristics for real-world applications.