Synthesis of NiMn-LDHs from spent manganate lithium batteries for efficient ozone decomposition in humid environment

Aiming to address the issues of ozone pollution and the more difficult disposal of employed lithium batteries, a novel nickel-manganese layered double hydroxide catalyst (Ni-MLB-LDH) was prepared by utilizing the spent manganate lithium battery (MLB) leaching solution as a raw material and applied to the treatment of ozone pollution. Ni-MLB-LDH has an ultra-high specific surface area (130.3 m²/g), smaller grain size and more defect sites than pure NiMn-LDH. Stability testing at RH= 60 % consistently maintained a high decomposition efficiency of over 99 %. XPS and EPR confirmed that Ni-MLB-LDH exhibited more surface oxygen vacancies, which plays a vital role in ozone decomposition. Additionally, incorporating an appropriate proportion of copper into NiMn-LDH can significantly enhance its catalytic activity, whereas doping with aluminium would decrease its catalytic activity. This method provides an emerging route for the resource utilization of spent MLBs and the synthesis of NiMn-LDH.