Isomer-Effects of Aminophenol Decorated Gold Nanoclusters for H2O2 Photoproduction via Two-Step One-Electron Oxygen Reduction Reaction

Gold (Au) nanoclustersare promising photocatalysts for biomedicine, sensing, and environmental remediation. However, the short carrier lifetime, inherent instability, and unclear charge transfer mechanism hinder their application. Herein, the Au nanoclusters decorated with three different isomers of o-Aminophenol, m-Aminophenol, and p-Aminophenol are synthesized, namely o-Au, m-Au, and p-Au, which achieve efficient hydrogen peroxide (H₂O₂) photoproduction through two-step one-electron oxygen reduction reaction (ORR). The interfacial kinetics for the photocatalytic process in this system are investigated in detail, in which, the isomer-effects of aminophenol decorated in Au nanoclusters are definitely elucidated by combining transient photovoltage (TPV), transient potential scanning (TPS), and photo-induced current (TPC) tests. The reaction pathway of o-Au, m-Au, and p-Au is confirmed to be the same through TPC. Although the conduction band values of o-Au, m-Au, and p-Au are essentially the same under working conditions, the values of surface effective charges (n_e) for both m-Au and p-Au are higher than that of o-Au. In addition, m-Au has a stronger adsorption capacity for O₂ and a faster ORR rate. Thus, the m-Au manifests the highest photocatalytic activity for the H₂O₂ photoproduction. This work shows a new way for the in-situ study on charge distribution and transfer on photocatalysts.