Enzyme-mimetic activity of sugar cane juice stabilized CuO nanospheres and CuO/GO nanocomposite: Green synthesis and applications

CuO nanosphere and CuO/GO nanocomposite have been synthesised via microwave irradiation using sugarcane juice. The juice containing sucrose and other biomolecules, act as complexing as well as capping agent and also dictate the self-assembly phenomenon during the formation of CuO NS and CuO/GO NC. The probable crystal growth mechanism proceeds via Ostwald ripening followed by oriented attachment mechanism which is also portrayed in this article. The synthesised CuO NS and CuO/GO NC were characterized using FTIR, XRD, XPS, TEM, SAED and UV–visible spectroscopy. The catalytic properties of the synthesised CuO NS and CuO/GO NC were evaluated for the aqueous phase catalytic reduction of toxic aromatic nitro compounds in the presence of NaBH4. Again, the peroxidase enzyme-like catalytic activity of synthesised CuO NS and CuO/GO NC were explored for colourimetric H2O2 sensing. Moreover, the antioxidant properties of synthesised CuO NS and CuO/GO NC are also examined by DPPH radical scavenging method. The formation of CuO/GO NC enhances the catalytic, sensing and antioxidant properties significantly compared to CuO NS due to the presence of highly conductive GO nanosheets.