Details

Autor(en) / Beteiligte

• Zhang, Bingyan
• Zhang, Xiaofan
• Xiao, Xin
• Shen, Yan

Titel

Photoelectrochemical Water Splitting SystemA Study of Interfacial Charge Transfer with Scanning Electrochemical Microscopy

Ist Teil von

• ACS applied materials & interfaces, 2016-01, Vol.8 (3), p.1606-1614

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Fast charge transfer kinetics at the photoelectrode/electrolyte interface is critical for efficient photoelectrochemical (PEC) water splitting system. Thus, far, a measurement of kinetics constants for such processes is limited. In this study, scanning electrochemical microscopy (SECM) is employed to investigate the charge transfer kinetics at the photoelectrode/electrolyte interface in the feedback mode in order to simulate the oxygen evolution process in PEC system. The popular photocatalysts BiVO4 and Mo doped BiVO4 (labeled as Mo:BiVO4) are selected as photoanodes and the common redox couple [Fe­(CN)6]3–/[Fe­(CN)6]4– as molecular probe. SECM characterization can directly reveal the surface catalytic reaction kinetics constant of 9.30 × 107 mol–1 cm3 s–1 for the BiVO4. Furthermore, we find that after excitation, the ratio of rate constant for photogenerated hole to electron via Mo:BiVO4 reacting with mediator at the electrode/electrolyte interface is about 30 times larger than that of BiVO4. This suggests that introduction of Mo6+ ion into BiVO4 can possibly facilitate solar to oxygen evolution (hole involved process) and suppress the interfacial back reaction (electron involved process) at photoanode/electrolyte interface. Therefore, the SECM measurement allows us to make a comprehensive analysis of interfacial charge transfer kinetics in PEC system.