Fabrication of LaCoO3/g-C3N5 Z-scheme photo catalyst for Allura Red dye degradation, ascorbic acid sensing and hydrogen evolution studies

Production of hydrogen by water splitting through photocatalytic process under visible light from waste water is one of the potential green energy technologies. In this study, LaCoO 3 , g-C 3 N 5 , LaCoO 3 /g-C 3 N 5 (1:1), (1:2) and (2:1) weight ratio nanocomposites (NCs) have been successfully synthesized using a solution combustion, hydrothermal and probe sonication method. The X-Ray Diffraction (XRD) confirmed the compound formed with the crystal size range 20 −30 nm. The studies of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) verify the morphology of the particles; band gap of the range 1.5–2 eV identified from Ultraviolet-Visible (UV–vis) studies. The findings demonstrate that Z-scheme heterostructures have developed on the interfaces between the layered flake-like g-C 3 N 5 and the perovskite-type oxides LaCoO 3 , which improve the absorption of visible light, the separation of photogenerated electron-hole pairs, and the transformation of photogenerated electrons. From the different ratio of synthesized nanoparticles (NPs), the LaCoO 3 /g-C 3 N 5 (2:1) shows enhanced photocatalytic activity of 99.87 % for degradation of Allura red dye in visible light irradiation. For the first time, the produced nanomaterials were tested for ascorbic acid sensing at extremely low concentrations with a 0.12 μM detection limit. The prepared nanomaterials were assessed for their electrocatalytic water splitting operation. Especially, the nanomaterial, LaCoO 3 /g-C 3 N 5 (2:1) reveal exceptional hydrogen evolution reaction (HER) and also oxygen evolution reaction (OER) capabilities with overpotential of 79 mV and 450 mV, respectively. Hence, the prepared nanomaterials are used for multifunctional applications. • LaCoO 3 /g-C 3 N 5 Z-scheme nanomaterials are prepared by probe sonication method. • The structure is confirmed using XRD and XPS analysis. • LaCoO 3 /g-C 3 N 5 (2:1) NC displays an excellent photocatalytic activity for water purification. • The maximum Allura Red dye degradation of 99.87% is achieved through Z-scheme heterojunction based viable photocatalytic system. • Selective detection of ascorbic acid using LaCoO 3 /g-C 3 N 5 (2:1) composite material.