A novel electrodeposited sandwich electrode with an efficient performance in complex water treatment

The use of an electrocatalytic surface coating is important in environmental remediation using electrochemistry. In this work, a novel Ti/calcined graphene (CG)/PbO2 sandwich electrode was successfully fabricated by a simple electrodeposition strategy for the efficient electrocatalytic oxidation of dye wastewater. The Ti/CG/PbO2 electrode coating was uniform and the structure was compact. As the electrocatalyst was rich in graphene, the novel electrode possessed higher oxygen evolution potential, lower charge transfer resistance, stronger stability, longer service life and higher instantaneous current efficiency (ICE) compared with traditional Ti/PbO2 electrode, thus exhibited better electrocatalytic oxidation activity and mineralization capacity. At a current density of 50 mA/cm2, up to 30 mg/L of methylene blue (MB) was almost completely oxidized in 1 h, while the MB removal efficiency at the Ti/PbO2 electrode only reached 78.2 ± 0.01%. Various influencing factors were designed to simulate the changes of the wastewater system, importantly and interestingly, the electrode still owned the advantages of high-efficiency electrocatalytic oxidation in the complex changes of a wastewater system like pH range of 3–11 and various electrolyte concentrations. The as-prepared electrode could still maintain good degradation efficiency after 30 cycles. It was worth mentioning that the COD value was reduced to about 0 when using this electrode to deal with the actual printing and dyeing wastewater. The results showed that the Ti/CG/PbO2 electrode was promising in the degradation of pollutants. [Display omitted] •A novel sandwich electrode with a 0.231 mm coating and graphene intermediate layer•Successfully fabricated by electrochemical deposition•Maintained excellent electrocatalytic oxidation efficiency•Coped with changes in the water body well•Proposed the degradation mechanism and mechanism analysis of the degradation process