Catalytic performance improvement of volatile organic compounds oxidation over MnOx and GdMnO3 composite oxides from spent lithium-ion batteries: Effect of acid treatment

In this work, cathode materials of spent lithium-ion ternary batteries are recovered and used as metal precursor to preparemulti-metal oxides MnOx(SY) and GdMnO3(SY) via combustion method and sol-gel method, respectively. Furthermore, a series ofMnO(x)(SY)-n and GdMnO3(SY)-n (n= 0.05, 0.10, 1.00, 4.00, n represents the dilute HNO3 concentration) catalysts are fabricated by acid treatment ofMnO(x)(SY) and GdMnO3(SY) samples and catalytic activities of oxygenated VOCs oxidation over all the prepared catalysts are investigated. Catalytic evaluation results show that acid-treated MnOx(SY)-0.10 and GdMnO3(SY)-0.05 samples perform the optimum VOCs removal efficiency respectively, which may be attributed to their obvious enhancement of physicochemical properties. In detail, MnOx(SY)-0.10 and GdMnO3(SY)-0.05 samples exhibit the larger specific surface area, bigger amount of surface high-valence metal ions (Mn4+, Co3+, Ni-3+), more abundant adsorbed oxygen species and better low-temperature reducibility, which can play a crucial role in the significant improvement of VOCs oxidation. In situ DRIFTS results imply that the possiblemain intermediates are -OCO, -COO and -C-O species produced during VOCs oxidation. Possible by-products are further determined via TD/GC-MS analysis. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rigths reserved.

Automated summary

The cathode materials of spent lithium-ion ternary batteries were used to prepare multi-metal oxides MnOx(SY) and GdMnO3(SY) via combustion and sol-gel methods. Acid-treated MnOx(SY)-0.10 and GdMnO3(SY)-0.05 samples showed the most efficient VOCs removal due to their enhanced physicochemical properties, such as larger specific surface area and better low-temperature reducibility.