(Invited) Electron Dynamics at the CuWO4/Electrocatalyst Interface for Photoelectrochemical Water Oxidation​

Abstract

Unraveling the electron dynamics at catalyst/electrode interfaces is critical for the development of design rules to produce efficient photoelectrochemical (PEC) water oxidation. Unlike the majority of photoanodes investigated for PEC water oxidation, the integration of catalysts with CuWO4 electrodes generally results in comparable or worse performance compared to the bare electrode. This is despite the fact that we have shown surface state recombination limits the water oxidation efficiency with CuWO4 electrodes and a catalytst ought to alleviate this reaction. Here we will present recent results which deepen the understanding of the energetics and electron-transfer processes at CuWO4/electrocatalyst interface which control the performance of such systems. Ni0.25Fe0.75Oy (denoted as Ni25) was chosen as a model catalyst, and through rigorous comparison of cyclic voltammetry, current transient and electrochemical impedance spectroscopy (EIS), intensity modulated photocurrent spectroscopy (IMPS), and dual-working electrode experiments measurements, we have been able to gain a significant insight into the role of the catalyst and the electron-transfer at the interface on the performance of CuWO4 for PEC water oxidation. General lessons and design rules for efficient PEC water splitting will be discussed.