Synthesis of novel CuNb2O6/g-C3N4 binary photocatalyst 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. In this study, CNO/g-CN (CuNb2O6/g-C3N4) photocatalyst synthesized via coprecipitation, followed by calcination which were characterized using physiochemical and photoelectrochemical approaches to identify their structural, photochemical and optical traits. The uniqueness of the synthesized photocatalyst is due to both its efficient photo-reduction 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 electronhole pairs. Free radical trapping experiments showed that O-center dot(2)- 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.

Automated summary

The further development of an efficient and sustainable water treatment requires the development of a very active and controllable photocatalyst. In this study, a CNO/g-CN photocatalyst was synthesized and shown to efficiently reduce Cr(VI) and degrade organic dyes under visible light. The unique characteristic of this photocatalyst is its low recombination rate of electron-hole pairs. This study opens an alternative route for effective binary photocatalysts in environmental remediation.