Laser-Reduced BiVO₄ for Enhanced Photoelectrochemical Water Splitting

Abstract

The present study proposes a laser irradiation method to superficially reduce BiVO4 photoelectrodes and boost their water oxidation reaction performance. The origin of this enhanced performance toward oxygen evolution reaction (OER) was studied using a combination of a suite of structural, chemical, and mechanistic advanced characterization techniques including X-ray photoelectron (XPS), X-ray absorption spectroscopy (XAS), electrochemical impedance spectroscopy (EIS), and transient absorption spectroscopy (TAS), among others. We found that the reduction of the material is localized at the surface of the sample and that this effect creates effective n-type doping and a shift to more favorable energy band positions toward water oxidation. This thermodynamic effect, together with the change in sample morphology to larger and denser domains, results in an extended lifetime of the photogenerated carriers and improved charge extraction. In addition, the stability of the reduced sample in water was also confirmed. All of these effects result in a two-fold increase in the photocurrent density of the laser-treated samples.

Rapid Synthesis of Ultrathin Ni:FeOOH with In Situ-Induced Oxygen Vacancies for Enhanced Water Oxidation Activity and Stability of BiVO4 Photoanodes

“…The Ni:FeOOH-Vo/BiVO 4 photoanode exhibits an IPCE value of ∼79% at 400 nm, which is ∼1.34 and 3.01 times higher than the FeOOH-Vo/BiVO 4 and pristine BiVO 4 photoanodes, respectively. From the IPCE curves, the corresponding integrated photocurrent density values were estimated (Figure S8), and the obtained results are consistent with the reported literature. − In addition, their calculated half-cell applied bias photon to current efficiencies (ABPEs) are presented in Figure c. The ABPE of the Ni:FeOOH-Vo/BiVO 4 photoanode could reach 1.62% at 0.71 V RHE , which is significantly higher than the FeOOH-Vo/BiVO 4 (0.76% at 0.71 V RHE ) and pristine BiVO 4 (0.18% at 0.71 V RHE ).…”

Light-Driven Nitrogen Fixation to Ammonia over Aqueous-Dispersed Mo-Doped TiO2 Colloidal Nanocrystals

“…On the other hand, the charge-transfer resistances of both samples (Figure c) decrease under illumination, as expected for a photoelectrode. − Additionally, under dark and illumination conditions, the Mo-doped sample shows lower values of R ct along the whole potential window, in good agreement with its higher photocurrent. Furthermore, both samples show a clear decrease in the capacitance with the applied potential (Figure d), as a consequence of an enhanced extraction of the photogenerated holes from the semiconducting absorber to the electrolyte, as expected for an n-type semiconductor. , Mo-doped TiO 2 shows higher capacitance values along the whole potential window, which can be related to a higher density of photogenerated holes. This difference is especially noticeable at low applied bias, in which photogenerated carriers are mainly accumulated at the photoelectrode/electrolyte interface before driving the catalytic reaction …”

Thioredoxin Reductase-Mediated Reaction Evokes In Situ Surface Polarization Effect on BiOIO3: Toward a New Sensing Strategy for Cathodic Photoelectrochemistry

“…In general, the smaller the impedance arc radius, the lower the interface resistance, and thus the higher the electron-transfer efficiency. 30 As can be seen from Figure 3B, the impedance arc of BiOIO 3 /GSH was smaller than that of pristine BiOIO 3 , denoting its higher electron-transfer efficiency. In addition, we also explored the photogenerated charge-transfer dynamics using PL and TRPL measurements.…”