Synthesis of Novel Cunb2o6/G-C3n4 Binary Photo-Catalyst Towards Efficient Visible Light Reduction of Cr (Vi) and Dyes Degradation for Environmental Remediation

The further development of an efficient and sustainable water treatment requires the development of a very active and controllable photocatalyst. The heterojunction is a promising site where the activity of such a photocatalyst can be enhanced. Organic dyes have become a severe concern in recent years owing to their significant presence in wastewater. Hexavalent Chromium (Cr (VI)) is a potential carcinogen also exhibiting great persistence in wastewater. So, a low-waste, high-performance materials is required to eliminate organic dyes and Cr (VI) from wastewater. This paper reports a CNO/g-CN (CuNb2O6/g-C3N4) photocatalyst synthesized via co-precipitation, followed by calcination. The photocatalyst was analyzed using X-Ray Powder Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX), Field Emission Scanning Electron Microscopy (FESEM), Ultraviolet Visible Diffused Reflection Spectroscopy (UV–Vis DRS), X-ray Photoelectron Spectroscopy (XPS), the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, Fourier Transform Infrared Spectroscopy (FTIR), Electrochemical Impedance Spectroscopy (EIS) and Photoluminescence (PL) and photocurrent density measurements. The uniqueness of the synthesized photocatalyst is due to both its efficient photoreduction of Cr (VI) and photo-degradation of Rhodamine B (RhB), Methylene Blue (MB) and Methyl Orange (MO) under visible light. The CNO/g-CN composite with 30% CNO heterojunctions exhibited the highest photocatalytic activity with Cr (VI) 92.80% photoreduction and efficiency degradation for RhB, MB, MO of 99.6%, 98.50%, 99.0%, respectively, with constant rate (k). This efficient photocatalytic activity is attributed to the lower recombination rate of electron-hole pairs. Free radical trapping experiments showed that •O2− and h+ play an important role in the photodegradation. The study, therefore, opens an alternative route in the synthesis of very efficient binary photocatalysts for application in environmental remediation