Improved catalytic oxidation of propylene glycol methyl ether over Sm–Mn and Sm–Co perovskite-based catalysts prepared by the recycling of spent ternary lithium-ion battery

The spent ternary lithium-ion batteries were utilized as the precursors to prepare Sm–Mn and Sm–Co perovskite oxides (SmMnO₃-spent ternary lithium-ion battery [STLIB] and SmCoO₃-STLIB) for the first time. Their catalytic activities were evaluated by catalytic oxidation of propylene glycol methyl ether. Compared with that of the catalysts synthesized by analytical reagents, the catalytic activities of SmMnO₃-STLIB and SmCoO₃-STLIB had been significantly enhanced. The analysis of X-ray photoelectron spectroscopy (XPS) showed that the molar ratios of Mn⁴⁺/Mn³⁺ and O_ads/O_latt of SmMnO₃-STLIB were higher than that of pure SmMnO₃ and the Co³⁺/Co²⁺ ratios of SmCoO₃-STLIB was much larger than that of pure SmCoO₃. The hydrogen temperature-programmed reduction (H₂-TPR) and N₂ adsorption-desorption tests determined that the reducibilities and specific surface areas of SmMnO₃-STLIB and SmCoO₃-STLIB were also superior to pure catalysts. Ultimately, the by-products of the catalytic oxidation of propylene glycol methyl ether over SmMnO₃-STLIB were also detected by gas chromatography–mass spectrometry (GC-MS). This work will provide a demonstration for the resource utilization of spent lithium ions batteries and the analysis of the increased activity obtained by using spent lithium ions batteries as the precursors to prepare catalysts.