ZnO@CdS heterostructures: an efficient photoanode for photoelectrochemical water splitting

Mahala, Chavi; Sharma, Mamta; Basu, Mrinmoyee

doi:10.1039/c9nj01373c

Cited by 65 publications

(45 citation statements)

References 55 publications

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“…The ZnO nanostructure was made up on FTO using a previously reported electrodeposition method with some modification . Before electrodeposition, FTO was cleaned.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…The band-energy position is determined with the help of the equations E CB = − X + 1 / 2 E g and E VB = E CB – E g , where X = electronegativity of the semiconductor, E g = band gap, and E VB and E CB = VB and CB edge potentials. The electronegativity values are reported as 5.79 and 4.64 eV for ZnO and C 3 N 4 , respectively. , From the calculated band-gap positions of ZnO and C 3 N 4 QDs, the CB energies are determined, and the values are −4.14 and −3.36 eV. Further, the VB energies of both ZnO and C 3 N 4 QDs are calculated, and the values are −7.44 and −5.92 eV (Scheme ).…”

Section: Photoelectrochemical Activitymentioning

confidence: 99%

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ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

Mahala

Sharma

Basu

2020

ACS Appl. Nano Mater.

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The efficient utilization of solar power is becoming an important strategy for its conversion into a storable, clean, and renewable energy source like H 2 . To generate H 2 as a chemical fuel from solar power, attempts are being made to establish photoelectrochemical (PEC) water splitting as an efficient, greener pathway. Here, the surfaces of ZnO 2D nanosheets are adorned by graphite-like carbon nitride (g-C 3 N 4 ) quantum dots (QDs) with the intention of developing efficient photoanodes. Sensitization of ZnO nanosheets with C 3 N 4 QDs leads to a more enhanced PEC performance than that of bare ZnO. The observed enhancement in PEC is due to the high light absorbance and photon-generated charge-carrier separation. The best-obtained ZnO/C 3 N 4 photoanode exhibits a nearly 2.29 times as high photocurrent density compared to bare ZnO. ZnO 2D sheets can generate a photocurrent density of 0.414 mA cm −2 at 0.5994 V versus reversible hydrogen electrode (RHE), whereas ZnO/C 3 N 4 can produce 0.952 mA cm −2 at 0.5994 V versus RHE under uninterrupted conditions of light illumination. Further, there is improvement in the observed PEC activity of the heterostructure because of enhancement in the carrier density. The carrier density enhances nearly 2.2 times in the heterostructure compared to the bare ZnO sheet. ZnO/C 3 N 4 shows a maximum photoconversion efficiency (η) of 0.70%. Both ZnO 2D sheets and the ZnO/C 3 N 4 heterostructure show efficient stability under chopped irradiation of light for 1000 s. The stability of ZnO/C 3 N 4 is also determined for 1 h under continuous illumination.

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“…The ZnO nanostructure was made up on FTO using a previously reported electrodeposition method with some modification . Before electrodeposition, FTO was cleaned.…”

Section: Experimental Sectionmentioning

confidence: 99%

Section: Photoelectrochemical Activitymentioning

confidence: 99%

ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

Mahala

Sharma

Basu

2020

ACS Appl. Nano Mater.

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“…There is a range of metal oxide semiconductors capable of driving PEC reactions in addition to the typical TiO 2 and SrTiO 3 semiconductors . Hematite (α‐Fe 2 O 3 ) for example has been well studied as a photoanode but commonly suffers from high levels of electron‐hole recombination .…”

Section: Introductionmentioning

confidence: 99%

PrFeO₃ Photocathodes Prepared Through Spray Pyrolysis

et al. 2020

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Perovskite oxides are receiving wide interest for photocatalytic and photoelectrochemical devices, owing to their suitable band gaps for solar light absorption and stability in aqueous applications. Herein, we assess the activity of PrFeO3 photocathodes prepared by using spray pyrolysis and calcination temperatures between 500 and 700 °C. Scanning electron microscopy shows corrugated films of high surface coverage on the conductive glass substrate. The electrochemically active surface area shows slight decreases with temperature increases from 500 to 600 and 700 °C. However, transient photocurrent responses and impedance spectroscopy data showed that films calcined at higher temperatures reduced the probabilities of recombination due to trap states, resulting in faster rates of charge extraction. In this trade‐off, a calcination temperature of 600 °C provided a maximum photocurrent of ‐130±4 μA cm−2 at +0.43 VRHE under simulated sunlight, with an incident photon‐to‐current conversion efficiency of 6.6 % at +0.61 VRHE and 350 nm and an onset potential of +1.4 VRHE for cathodic photocurrent.

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“…First, FTO was cleaned following the same procedure as that mentioned in ref . After that, the ZnO nanostructure was synthesized through the electrodeposition technique on FTO.…”

Section: Methodsmentioning

confidence: 99%

Near-Field and Far-Field Plasmonic Effects of Gold Nanoparticles Decorated on ZnO Nanosheets for Enhanced Solar Water Splitting

Mahala

Sharma

Basu

2020

ACS Appl. Nano Mater.

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Photoelectrochemical (PEC) water splitting has become an essential tool for the straightforward production of hydrogen (H 2 ) from solar energy. In this respect, earth-abundant materials can be exploited to have high solar-to-H 2 conversion efficiencies, which may further smoothen the practical applicability of this technique. Here, an efficient photoanode and vertically grown ZnO are developed for the PEC water-splitting reaction. To understand the plasmonic effect, variable sizes of gold nanoparticles (Au NPs) are fabricated and adorned on the surface of two-dimensional (2D) ZnO nanosheets. The sizes of the Au NPs are varied from 12 to 135 nm, and the impact of the variable sizes on ZnO is determined under different light illumination conditions. The influences of lightabsorbing and -scattering effects by Au NPs are studied separately. The ability of light trapping for enhancement of the PEC water-splitting performance of ZnO/Au through light-scattering and -absorbing effects is determined. Upon back illumination, the light-scattering effect predominates and 2D ZnO sheets decorated with 55 nm Au NPs show a maximum photocurrent density. Au NPs of 55 nm on ZnO can generate a maximum photoconversion efficiency of 0.514% under back illumination by successfully increasing the light absorbance of the material through the scattering effect. On the other hand, under the front illumination, the light-concentrating effect predominates and ZnO nanosheets decorated with 35 nm Au NPs result in a maximum enhancement in the photoconversion efficiency (0.605%). The stabilities of bare ZnO, ZnO/Au-55, and ZnO/Au-35 are determined for 1000 s under back illumination, and different physical techniques are employed after PEC water splitting to confirm the morphological and structural robustness. Hence, upon application of two different sizes of Au NPs on ZnO nanosheets, the plasmonic enhancement (radiative light-scattering and -concentrating) effect of Au is studied, and the mechanisms are explained.

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ZnO@CdS heterostructures: an efficient photoanode for photoelectrochemical water splitting

Abstract: CdS nanoparticles attached to ZnO 2D sheets help to improve light absorbance, leading to enhanced photoelectrochemical water splitting performance.

Cited by 65 publications

References 55 publications

ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

PrFeO₃ Photocathodes Prepared Through Spray Pyrolysis

Near-Field and Far-Field Plasmonic Effects of Gold Nanoparticles Decorated on ZnO Nanosheets for Enhanced Solar Water Splitting

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ZnO@CdS heterostructures: an efficient photoanode for photoelectrochemical water splitting

Abstract: CdS nanoparticles attached to ZnO 2D sheets help to improve light absorbance, leading to enhanced photoelectrochemical water splitting performance.

Cited by 65 publications

References 55 publications

ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting

PrFeO3 Photocathodes Prepared Through Spray Pyrolysis

Near-Field and Far-Field Plasmonic Effects of Gold Nanoparticles Decorated on ZnO Nanosheets for Enhanced Solar Water Splitting

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Product

Resources

About

PrFeO₃ Photocathodes Prepared Through Spray Pyrolysis