Strong effect of multi-electron oxygen reduction reaction on photocatalysis through the promotion of interfacial charge transfer

An efficient visible-light-driven photocatalyst with interface charge transfer (IFCT) effect was achieved by assembling Fe-porphyrin based conjugated microporous polymer on TiO2 microspheres. It was revealed that IFCT effect played a crucial role in the enhancement of photocatalytic performance. In addition, the oxygen reduction reaction (ORR) activity of TiO2 was enhanced in the presence of Fe-porphyrin based conjugated microporous polymer and IFCT effect was promoted obviously due to the high ORR activity. It's speculated that multi-electron ORR could accelerate the consumption of photoinduced electrons, retarding the recombination of photoinduced holes and electrons in the IFCT process, leaving more high-oxidizing photoinduced holes in the valance band of TiO2 for further degradation. What's more, to further clarify the relationship between multi-electron ORR and IFCT effect, the influence of electron transfer number on the generation of photoinduced holes in the IFCT process was studied, and it was believable that four-electron oxygen reduction process was better able to accelerate the generation of photoinduced holes in the IFCT process than two-electron oxygen reduction process, resulting in higher photocatalytic activity.