Design of novel egg-shaped GdVO₄ photocatalyst: a unique platform for the photocatalyst and supercapacitors applications

In recent years, synthesis of rare earth vanadates using soft chemical routes is considered to be an exhilarating area of research with extensive applications owing to its cost-effectiveness, cleaner, and easier synthesis routes. In this work, we have prepared egg-shaped gadolinium vanadate (GdVO₄) nanoparticles using the simple route using 1-methyl imidazole as a novel stabilizing agent. Furthermore, the synthesized GdVO₄ is used as photocatalyst towards the photodegradation of various carcinogenic dyes namely methylene blue (Me-B), rhodamine-B (Rho-B), and malachite green (Ma-G) under visible light. For structural confirmation, the synthesized GdVO₄ nanoparticles were systematically analyzed using SEM, HRTEM, EDS, XRD, UV–vis DRS analysis, and electrochemical measurements, respectively. The characterization studies revealed that the presence of the pure phase of GdVO₄ nanoparticles with uniform egg-shaped particles with an average size of about 15 nm. The electrochemical studies confirmed that the ideal nature of GdVO₄ as electrode material for supercapacitor. The consequence of the photocatalyst used, reaction time and kinetic parameters, and regeneration of photocatalyst were further investigated. The UV–vis DRS spectroscopy results revealed that the absorbance maxima of the GdVO₄ have extended to all UV and visible light regions with a narrow bandgap energy of (2.2 eV) for the effective degradation of various dyes. The kinetic analysis of dyes degradation using the GdVO₄ nanoparticles agreed with the pseudo-first-order kinetics (Langmuir–Hinshelwood model), and it is obvious that the GdVO₄ photocatalyst could remove nearly Me-B (87.8%), Rho-B (89.2%), and Ma-G (96.2%), respectively.