Temperature Effect on Photoelectrochemical Water Splitting: A Model Study Based on BiVO4 Photoanodes

Photoelectrochemical (PEC) water splitting is typically studied at room temperature. In this work, the temperature effect on PEC water splitting is studied using crystalline BiVO4 thin film photoanode as a model system. Systematic temperature-dependent electrochemical study demonstrates that the PEC activity is boosted at elevated electrolyte temperatures and indicates that thermal energy plays a main role in improving charge carrier transport in the bulk of BiVO4. Irreversible surface reconstruction is observed after PEC reactions at elevated temperature in the presence of hole scavengers, with regularly spaced stripes emerging on BiVO4 grains. The surfacere-constructed photoanode exhibits up to 40% improvement in photocurrent densities and similar to 0.25 V shift of photocurrent onset to favorable direction. Detailed investigation shows the formation of an amorphous layer without stoichiometric change at the reconstructed surface. This work provides insights of the temperature effect on the photoelectrode in solar water splitting and reveals the non-negligible effect of hole scavengers in photoelectrochemical measurement.

Automated summary

The study found that the PEC activity of water splitting is enhanced at higher electrolyte temperatures due to the role of thermal energy in improving charge carrier transport in BiVO4. Additionally, irreversible surface reconstruction was observed at elevated temperatures in the presence of hole scavengers.