Volatile　organic　compounds　(VOCs)　from　different　industrial　processes　cause　harm　to　the　environment　and　human　health.　Highly　active　and　stable　monolithic　catalysts　play　a　vital　role　in　VOCs　degradation　in　practical　application.　Here,　the　Mn-based　spinel　monolithic　catalyst　(BTMn　catalyst)　was　prepared　from　bauxite　and　Mn(OH)2　using　phase　inversion　method,　and　then　further　treated　with　NaOH　solution　to　obtain　the　BTMn-OH　catalyst.　The　temperature　for　90　%　of　acetone　conversion　over　BTMn-OH　is　86　°C　lower　than　that　over　BTMn.　The　CO₂　selectivity　of　BTMn-OH　is　higher　by　8–28　%　than　that　of　BTMn.　The　reaction　rate　of　BTMn-OH　is　13　times　higher　than　that　of　BTMn　at　160　°C.　Compared　to　BTMn,　abundant　Lewis　acid　sites　in　BTMn-OH　enhance　its　adsorption　capacity　for　acetone.　After　alkali　treatment,　BTMn-OH　exhibits　a　higher　surface　proportion　of　Mn3O4/MnAl2O4　phases,　accompanied　by　more　surface　adsorbed　oxygen　species　and　Mn³　⁺,　which　collectively　contribute　to　its　excellent　low-temperature　acetone　oxidation　performance.　BTMn-OH　also　exhibits　excellent　catalytic　stability.　Formic　acid　degradation　is　the　rate-limiting　step　for　BTMn-OH,　accompanied　by　the　rapid　conversion　of　methanol.　This　work　provides　a　new　insight　into　the　design　of　highly　active　and　stable　spinel　based　monolithic　catalysts　for　efficient　purification　of　VOCs.　©　2025　Elsevier　B.V.