Empirical Analysis of the Photoelectrochemical Impedance Response of Hematite Photoanodes for Water Photo-oxidation.
Dino KlotzDaniel A GraveHen DotanAvner RothschildPublished in: The journal of physical chemistry letters (2018)
Photoelectrochemical impedance spectroscopy (PEIS) is a useful tool for the characterization of photoelectrodes for solar water splitting. However, the analysis of PEIS spectra often involves a priori assumptions that might bias the results. This work puts forward an empirical method that analyzes the distribution of relaxation times (DRT), obtained directly from the measured PEIS spectra of a model hematite photoanode. By following how the DRT evolves as a function of control parameters such as the applied potential and composition of the electrolyte solution, we obtain unbiased insights into the underlying mechanisms that shape the photocurrent. In a subsequent step, we fit the data to a process-oriented equivalent circuit model (ECM) whose makeup is derived from the DRT analysis in the first step. This yields consistent quantitative trends of the dominant polarization processes observed. Our observations reveal a common step for the photo-oxidation reactions of water and H2O2 in alkaline solution.
Keyphrases
- solid state
- visible light
- electron transfer
- quantum dots
- high resolution
- hydrogen peroxide
- single molecule
- density functional theory
- sensitive detection
- label free
- electronic health record
- gene expression
- magnetic resonance
- extracellular matrix
- risk assessment
- dual energy
- magnetic resonance imaging
- human health
- anaerobic digestion
- high efficiency