The critical role of furfural alcohol in photocatalytic H2O2 production on TiO2

Isopropanol is frequently employed as the electron donor to facilitate hole transfer and promote photocatalytic H2O2 production. However, the role of alcohols can be more complicated due to the interaction with TiO2. According to a comparison of aliphatic, aromatic and aromatic heterocyclic alcohols on photocatalytic H2O2 production on TiO2, furfural alcohol (FFA) displays superior capability to others. The presence of alcohols with aromatic structures can significantly accelerate formation and suppress decomposition of H2O2. Moreover, furfural alcohol tends to form more stable complexes on TiO2 surface, which can negatively shift the flat band position, induce visible light activity, and boost two-electron reduction of oxygen. The altered electron transfer pathway for H2O2 production was indicated by the Koutecky-Levich plots, the less pH dependence, and the signals of peroxide species in Raman spectra. This study brings insights for modulating the interfacial oxygen reduction and designing highly efficient and selective H2O2 production photocatalytic systems.