Quantitative hole collection for photoelectrochemical water oxidation with CuWO<sub>4</sub>

Gao, Yuan; Hamann, Thomas W.

doi:10.1039/c6cc09029j

Cited by 62 publications

(59 citation statements)

References 30 publications

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“…34 Previous studies pointed out that significant dark current is observed if CuWO4 electrodes are in contact with Na2SO3-and H2O2-containing solutions. 35 Therefore, the performance of CuW0.5Mo0.5O4…”

Section: Sacrificial Agentsmentioning

confidence: 99%

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Polo

Nomellini

Grigioni

et al. 2020

ACS Appl. Energy Mater.

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The need for stable oxide-based semiconductors with narrow band gap, able to maximize the exploitation of the visible light portion of the solar spectrum, is a challenging issue for photoelectrocatalytic (PEC) applications. In the present work CuW1−xMoxO4 (Eg = 2.0 eV for x = 0.5), exhibiting a significantly reduced optical band gap Eg compared to isostructural CuWO4 (Eg = 2.3 eV), was investigated as photoactive material for the preparation of photoanodes. CuW0.5Mo0.5O4 electrodes with different thickness (80-530 nm), prepared by a simple solution-based process in the form of multilayer films,

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Section: Sacrificial Agentsmentioning

confidence: 99%

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Polo

Nomellini

Grigioni

et al. 2020

ACS Appl. Energy Mater.

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“…must be taken because the photocurrent measured with the hole scavenger may not be the same as Jh without the hole scavenger due to spurious effects such as current doubling, 19 or due to changes in the surface potential and space charge characteristics that result from the different surface reaction, as will be discussed in more detail below.…”

Section: Measuring the Charge Transfer Efficiencymentioning

confidence: 99%

Accurate determination of the charge transfer efficiency of photoanodes for solar water splitting

Klotz

Grave

Rothschild

2017

Phys. Chem. Chem. Phys.

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The oxygen evolution reaction (OER) at the surface of semiconductor photoanodes is critical for photoelectrochemical water splitting. This reaction involves photo-generated holes that oxidize water via charge transfer at the photoanode/electrolyte interface. However, a certain fraction of the holes that reach the surface recombine with electrons from the conduction band, giving rise to the surface recombination loss. The charge transfer efficiency, η, defined as the ratio between the flux of holes that contribute to the water oxidation reaction and the total flux of holes that reach the surface, is an important parameter that helps to distinguish between bulk and surface recombination losses. However, accurate determination of η by conventional voltammetry measurements is complicated because only the total current is measured and it is difficult to discern between different contributions to the current. Chopped light measurement (CLM) and hole scavenger measurement (HSM) techniques are widely employed to determine η, but they often lead to errors resulting from instrumental as well as fundamental limitations. Intensity modulated photocurrent spectroscopy (IMPS) is better suited for accurate determination of η because it provides direct information on both the total photocurrent and the surface recombination current. However, careful analysis of IMPS measurements at different light intensities is required to account for nonlinear effects. This work compares the η values obtained by these methods using heteroepitaxial thin-film hematite photoanodes as a case study. We show that a wide spread of η values is obtained by different analysis methods, and even within the same method different values may be obtained depending on instrumental and experimental conditions such as the light source and light intensity. Statistical analysis of the results obtained for our model hematite photoanode show good correlation between different methods for measurements carried out with the same light source, light intensity and potential. However, there is a considerable spread in the results obtained by different methods. For accurate determination of η, we recommend IMPS measurements in operando with a bias light intensity such that the irradiance is as close as possible to the AM1.5 Global solar spectrum.

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“…A diffusion length of ∼25 nm using the peak mobility and τ 1 as carrier lifetime is derived for CuWO 4 which is superior to the WO 3 sample and close to BiVO 4 [25]. Quantitative hole collection [15,67] has been reported for films fabricated by atomic layer deposition (ALD) and electrochemical preparation under usage of appropriate scavengers to circumvent recombination via midgap surface traps [68] and ameliorate the slow oxidation kinetics [69] at the CuWO 4 surface. A similar occupied midgap state corresponding to Cu 3d states was predicted in a combined photoelectrochemical and computational study [70].…”

Section: Resultsmentioning

confidence: 97%

“…2.3 eV) than BiVO 4 (2.4-2.5 eV) and excellent stability in aqueous electrolytes [13,14]. A recent report has shown that the catalytic activity of CuWO 4 for water oxidation is very good and quantitative hole collection at larger bias potentials (>1.23 V vs. RHE) was possible [15]. However, a major factor limiting the efficiency is the poor charge separation efficiency and short charge carrier diffusion length leading to enhanced recombination especially at lower bias potentials [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO₄, CuO, and WO₃ Thin Films for Photoelectrocatalysis

Hirst

Müller

Peeters

et al. 2019

Zeitschrift Für Physikalische Chemie

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The temporal evolution of photogenerated carriers in CuWO4, CuO and WO3 thin films deposited via a direct chemical vapor deposition approach was studied using time-resolved microwave conductivity and terahertz spectroscopy to obtain the photocarrier lifetime, mobility and diffusion length. The carrier transport properties of the films prepared by varying the copper-to-tungsten stoichiometry were compared and the results related to the performance of the compositions built into respective photoelectrochemical cells. Superior carrier mobility was observed for CuWO4 under frontside illumination.

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Quantitative hole collection for photoelectrochemical water oxidation with CuWO₄

Cited by 62 publications

References 30 publications

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Accurate determination of the charge transfer efficiency of photoanodes for solar water splitting

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO₄, CuO, and WO₃ Thin Films for Photoelectrocatalysis

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Quantitative hole collection for photoelectrochemical water oxidation with CuWO4

Cited by 62 publications

References 30 publications

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Effective Visible Light Exploitation by Copper Molybdo-tungstate Photoanodes

Accurate determination of the charge transfer efficiency of photoanodes for solar water splitting

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO4, CuO, and WO3 Thin Films for Photoelectrocatalysis

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Product

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Quantitative hole collection for photoelectrochemical water oxidation with CuWO₄

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO₄, CuO, and WO₃ Thin Films for Photoelectrocatalysis