Sonochemical preparation and characterization of ErVO4/g-C3N4 nano-photocatalysts for removal of water-soluble organic dyes under visible light exposures

• Sonochemical synthesis of nano-ErVO 4 /g-C 3 N 4 for photocatalyst development. • Polymeric template’s type affected the structural-morphological features of ErVO 4 samples. • Tailoring the energy band gaps for higher degradation yield under visible light. • Achieving the highest MB degradation rate (85.43 %) by nanocomposites having 20.0 wt % ErVO 4 . • Understanding of kinetics of the photocatalysis and the role of scavengers. Modern society's need for potential waste water purification has been intensified by the ongoing energy crisis and environmental pollution resulting from the consumption of manufactured coloring agents. However, expanding the light absorption threshold of nanostructured materials from UV to visible region has become a challenge to achieve high photocatalytic performance. This work focuses on the development and exploitation of simulated sunlight over novel ErVO 4 /g-C 3 N 4 (EV-CN) nanophotocatalyst, wherein melamine as the CN precursor provided capable matrix for insitu-precipitation of EV nanostructures thorough sonication pathway and subsequent calcination at 550 °C for 5 h. Expanded studies of EV-based nanoproducts depicted the nucleation and growth mechanism of particles by changing the operational factors such as type of polymeric templates, concentration of PEG, sono-reaction time, and sonication wave’s absence. Usage of ultrasonic irradiation for 30 min at 60 W and a ratio of 0.5:1 for PEG:Er 3+ could offer the most uniform morphology of tetragonal EV phase with mean particle size of 37.65 nm, specific surface area of 36.14 m 2 /g, and bandgap value of 3.5 eV with the aid of diverse identification techniques. Benefited form 20 wt% of EV dispersed on the CN, a maximum MB photodegradation of 85.43 % (k app = 0.016 min –1 ) was achieved under visible light irradiation after 120 min compared with bare EV, CN, and other counterparts of this composition. Scavenging outcomes of deletion MB molecules revealed the photo-induced superoxide radicals and holes as basic driving forces in enhanced photoactivity of the EV-CN semiconductor. Surprisingly, the optimum EV-CN photoctatlysts containing 20 wt% is endowed with good reusability and photo-efficiency of 76.51 % after four cycling runs. We believe that the junction/interface generated between nano-EV and CN nanolayers with the staggered band structure can modify the inherent problems of catalysts in terms of the life time of photogenerated charge carriers and facilities efficiency of solar energy harvesting.