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.