Oxygen Vacancy-Engineered Ni:Co3O4/Attapulgite Photothermal Catalyst from Recycled Spent Lithium-Ion Batteries for Efficient CO2 Reduction

Accelerated industrialization and surging energy demands have led to continuously rising atmospheric CO2concentrations. Developing sustainable methods to reduce atmospheric CO2levels is crucial for achieving carbon neutrality. Concurrently, the rapid development of new energy vehicles has driven a significant increase in demand for lithium-ion batteries (LIBs), which are now approaching an end-of-life peak. Efficient recycling of valuable metals from spent LIBs represents a critical challenge. This study employs conventional hydrometallurgical processing to recover valuable metals from spent LIBs. Subsequently, Ni-doped Co3O4(Ni:Co3O4) supported on the natural mineral attapulgite (ATP) was synthesized via a sol–gel method. The incorporation of a small amount of Ni into the Co3O4lattice generates oxygen vacancies, inducing a localized surface plasmon resonance (LSPR) effect, which significantly enhances charge carrier transport and separation efficiency. During the photocatalytic reduction of CO2, the primary product CO generated by the Ni:Co3O4/ATP composite achieved a high production rate of 30.1 μmol·g−1·h−1. Furthermore, the composite maintains robust catalytic activity even after five consecutive reaction cycles.