Ionic–Covalent Bond-Mediated Electron-Rich Lattice Oxygen for Solar-Driven Acetic Acid Abatement

Domestic waste generates volatile fatty acids (VFAs) and emits strong malodors that reduce environmental comfort. The generation of these odor-causing molecules usually occurs in relatively high-humidity conditions, which speed up the deterioration of adsorbents, creating secondary waste from frequent replacement. Herein, we report a lithium-doped manganese dioxide (Li–MnO₂) photothermal system that sustainably degrades acetic acid (CH₃COOH, a key VFA). Mechanistic studies reveal the ionic bond in Li–O localizes electrons at the oxygen atom, while the covalent bond in Mn–O establishes an efficient electron transport channel. This electron-rich oxygen can cleave the O–H bond in H₂O with an ultra-low energy barrier of 0.01 eV, generating dihydroxy groups, which subsequently initiate a nucleophilic attack on the O–H and C–H bonds in CH₃COOH molecules. The introduction of light not only efficiently converts the material surface into thermal energy, but it also triggers electron rearrangement. The engineered Li–MnO₂ catalyst demonstrates complete CH₃COOH degradation at 291 mW cm^–2. A modular photothermal purification device demonstrates above 1000 h odor removal efficiency in municipal waste scenario. We anticipate this work will enable perpetual CH₃COOH removal from domestic waste without external energy input, offering a sustainable solution for odor control in waste management.