Operando interfacial kinetic study of H2O2 photoproduction over carbon dots stabilized gold nanoclusters

Understanding photocatalytic processes of nanoclusters at the nanoscale remains a challenge. Here, we synthesized two kinds of gold nanoclusters stabilized by thiol ligands (AuNCs) and carbon dots (AuCDs) to study their interfacial kinetics in photocatalytic H 2 O 2 production. Three operando testing methods, including transient photovoltage (TPV), transient potential scanning (TPS) and photo-induced current (TPC), are used to investigate the influence of carbon dots (CDs) on catalytic processes. While AuNCs and AuCDs show similar O 2 adsorption abilities, AuCDs exhibit a lower reaction rate due to less surface effective photoelectrons. The AuNCs utilize their own ligands to consume photo-generated holes while the presence of CDs in AuCDs changes this way and providing stable catalytic sites for water oxidation reaction. Additionally, with the addition of CDs, the oxygen reduction reaction pathway changes from a two-step one electron process to a one-step two electron process. This work provides new insights for understanding the photocatalytic processes.