Regenerative, low-cost and switchable photoelectrochemical sensor for detection of Cu2+ using MnO2-GO heterojunction

In this work, we investigate the properties of manganese dioxide (MnO2) and graphene oxide (GO) to develop a new photoelectrochemical (PEC) sensor-based MnO2-GO heterojunction on stainless steel electrode for chemical detection of copper (Cu(II)) cation. During the PEC detection process and using chronoamperometry, the photocurrent density increases gradually with the addition of incremental Cu2+ concentration, achieving a relatively low detection limit (0.9120 µM) and a linear interval range from 0.01 to 110 µM with high selectivity and stability under neutral aqueous solution (pH 7.00). In addition, the PEC change of electrode state in presence of Cu(II) cation requires the oxidized state of MnO2-GO heterojunction; this can be reached by applying anodic potential to the electrode (E =  + 0.8 V). Thus, a switchable, low-cost, regenerative, and sensitive PEC sensor based on the change of MnO2-GO heterojunction surface state permits the selective detection of copper.