Electrochemical detection and catalytic removal of 4-nitrophenol using CeO2-Cu2O and CeO2-Cu2O/CH nanocomposites

A facile, cheap and efficient system has been developed for selective detection and removal of 4-nitrophenol. Herein, cerium oxide-copper oxide (CeO2-Cu2O) and CeO2-Cu2O/chitosan (CeO2-Cu2O/CH) nanocomposites were coated on glassy carbon electrode to evaluate their electrochemical behavior toward 4-nitrophenol via cyclic voltammetry. The response of coated electrodes toward 4-nitrophenol were remarkable, in which the reduction peak current of 4-nitrophenol was increased as compared to bare electrode. This specifies that such nanocomposites significantly boost the electrochemical reduction of 4-nitrophenol and therefore, we demonstrated that the nanocomposites exhibit outstanding selectivity and sensitivity toward 4-nitrophenol detection. The effects of different parameters including pH and scan rate were tested. The reduction peak current of 4-nitrophenol is proportionate with its concentration in the range 74–375 μM, and the correlation coefficient was 0.998. The detection limit is 2.03 μM (S/N = 3). This simplistic system was effectively implemented to the detection of 4-nitrophenol in real water samples, with reasonable recovery values (92.5–99.85%). Furthermore, we demonstrated that the nanocomposite displays an excellent catalytic ability for the transformation reaction of 4-nitrophenol to 4-aminophenol by NaBH4. Such a system could be applicable for diverse applications in catalysis, sensing and environmental sciences.