Efficient inhibition of photogenerated electron-hole recombination through persulfate activation and dual-pathway degradation of micropollutants over iron molybdate

Photogenerated electron-hole recombination has been a bottleneck problem for photocatalytic reactions for a long time. Herein, we propose an efficient solution strategy through capturing electrons and holes with environmental factors. In this study, nanoscale iron molybdate (Fe2(MoO4)3) was successfully synthesized, characterized and used in a heterogeneous photo-combined persulfate (PS) activation (HPPA) process for micropollutant removal. The reaction rate in this system was ˜98 and ˜59 times higher for Fenton-like and photocatalytic oxidation alone, respectively, which was attributed to strong synergistic effects of HPPA process. During the HPPA reaction, PS could quickly capture the photogenerated electrons to produce sulfate radicals (SO4−), which was further converted to hydroxyl radicals (•OH) in water. Induced by PS, the electron-rich pollutants could actively capture the holes and be oxidized and degraded. This synergistic process not only inhibited the electron-hole recombination but also enabled rapid dual-pathway degradation of pollutants through free radical attack and hole oxidation.