GO/PbO₂ Composite with Heterostructure for Electrocatalytic Degradation of Ethylene Carbonate in Spent Lithium-Ion...

Electrocatalytic oxidation offers an efficient and environmentally compatible strategy for the treatment of organic waste. To mitigate the ecological risks caused by the discharge of organic electrolytes from spent lithium-ion batteries, the development of high-performance electrode materials is of great importance. Herein, we fabricate three graphene oxide (GO)/PbO₂ composite electrodes: GO-PbO₂-50, GO-PbO₂-100, and GO-PbO₂-150, for the electrocatalytic oxidation of ethylene carbonate (EC) that is the main organic electrolyte in spent lithium-ion batteries. The formation of a GO/β-PbO₂/α-PbO₂ heterostructure decreases the β-PbO₂ crystal size, increases active sites, enhances ·OH radical generation, reduces interfacial charge transfer resistance, and elevates the oxygen evolution potential. GO-PbO₂-100 electrode exhibits the best catalytic activity, achieving almost complete mineralization of 1000 mg L^-1 EC to CO₂ and H₂O under a current density of 40 mA cm^-2. The electrochemical degradation of EC adheres to pseudo-first-order kinetics. Density functional theory calculations confirm that the GO/PbO₂ composite significantly decreases the Gibbs free energy of each oxidation step, particularly for the rate-determining step, thereby enhancing the reaction spontaneity. Therefore, the GO/PbO₂ composite with a heterostructure is a promising catalyst for the efficient degradation of organic waste in spent lithium-ion batteries.