Triphasic WO3/Periodic Acid System for Amine-Specific Complexation and Ultrafast Photocatalytic Mineralization with Exceptional Quantum Efficiency

Volatile aliphatic amines (VAAs) are toxic pollutants with low odor thresholds, contributing to the formation of smog, aerosols, and carcinogenic nitrosamines, but their removal is hindered by complex degradation pathways and the generation of non-volatile by-products. This study introduces a novel triphasic photocatalytic system consisting of periodic acid (PA), tungsten trioxide (WO 3 ), and an in situ surface water layer for the mineralization of VAAs under visible light. PA protonates the VAAs molecules, altering the hydroxyl radical attack pathway and subsequently forming vicinal amino-alcohol intermediates, which further react with PA via amine-specific complexation to induce rapid C─C bond cleavage. This leads to the generation of smaller aldehydes and acids, which are then rapidly mineralized into CO 2 . The PA/WO 3 system mineralizes 120 ppmv n-propylamine ( n-PrA ) with an exceptionally high apparent quantum efficiency (AQE) of 91.8%, compared with only 9.4% for acetaldehyde under identical conditions. This process prevents secondary pollution by dissolving the ammonium product in the in situ surface water layer. These results highlight the outstanding performance of PA/WO 3 for eliminating various VAAs from air, establishing it as a highly effective and selective method for purifying amine-contaminated air.