H:ZnO Nanorod-Based Photoanode Sensitized by CdS and Carbon Quantum Dots for Photoelectrochemical Water Splitting

Vuong, Nguyen Minh; Reynolds, John L.; Conte, Eric D.; Lee, Yong‐Ill

doi:10.1021/acs.jpcc.5b08724

Cited by 66 publications

(33 citation statements)

References 42 publications

(122 reference statements)

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“…In terms of nanostructuring, ZnO‐based photoanodes with 1 D nanostructures are attractive candidates because they have large surface‐to‐volume ratios, low concentration of grain boundaries, and benign carrier‐transport properties . However, the anodic decomposition potential of ZnO lies in between the water reduction and oxidation potentials, which leads to photocorrosion of the ZnO photoanode during the photoelectrochemical reactions . In this context, seeking a semiconductor with suitable band alignments as a protective layer and a possible catalyst layer may be an effective way to improve its stability, thus extending its application in the field of photoelectrochemical water splitting.…”

Section: Introductionmentioning

confidence: 99%

Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Qin

et al. 2017

ChemSusChem

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Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet-chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe O shell. This shell, in which the thickness can be tuned by varying reaction times, forms an intact interface with ZnO NWs, thus protecting ZnO from corrosion in a basic solution. The reverse energetic heterojunction nanowires are subsequently activated by introducing an amorphous iron phosphate, which substantially suppressed surface recombination as a passivation layer and improved photoelectrochemical performance as a potential catalyst. Compared with pure ZnO NWs (0.4 mA cm ), a maximal photocurrent of 1.0 mA cm is achieved with ZnO/Fe O core-shell NWs and 2.3 mA cm was achieved for the PH -treated NWs at 1.23 V versus RHE. The PH low-temperature treatment creates a dual function, passivation and catalyst layer (Fe PO ), examined by X-ray photoelectron spectroscopy, TEM, photoelectrochemical characterization, and impedance measurements. Such a nano-composition design offers great promise to improve the overall performance of the photoanode material.

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Section: Introductionmentioning

confidence: 99%

Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Qin

et al. 2017

ChemSusChem

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“…This may be due to the strong ability of the CQDs to capture and transfer the photo-generated carriers. 36 Furthermore, both the Bi 2 WO 6 /FTO and CQDs-Bi 2 WO 6 /FTO electrodes in the absence of methanol are severely reduced with an increase in time. On the contrary, the photocurrent densities of both electrodes in 1 M KOH + 0.5 M CH 3 OH aqueous solution show an increasing tendency and then reach a plateau.…”

Section: Methanol Oxidationmentioning

confidence: 99%

Carbon quantum dot sensitized Pt@Bi₂WO₆/FTO electrodes for enhanced photoelectro-catalytic activity of methanol oxidation

2017

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Carbon quantum dot sensitized Pt@Bi 2 WO 6 /FTO electrodes (simplified as CQDs-Pt@Bi 2 WO 6 /FTO) were successfully prepared by loading platinum particles onto Bi 2 WO 6 nanoplates via a photo-deposition method and sensitized carbon quantum dots (CQDs) via a dip-coating method. The photoelectrocatalytic properties of the Pt@Bi 2 WO 6 /FTO and CQDs-Pt@Bi 2 WO 6 /FTO electrodes for methanol oxidation were investigated. The results indicated that the CQDs-Pt@Bi 2 WO 6 /FTO electrode shows higher photoelectro-catalytic activity and better stability than that of the Pt@Bi 2 WO 6 /FTO electrode. The higher photoelectro-catalytic performance for methanol oxidation was attributed due to the special synergetic effects between the photocatalytic and electrocatalytic process under solar light irradiation.More importantly, the introduction of CQDs broaden the photoresponse range of the Bi 2 WO 6 material and improves the mobility of the photocarriers. Meanwhile, the doped CQDs act as preferential adsorption sites for the intermediate carbonaceous species during methanol oxidation. This not only alleviates CO poisoning towards the Pt particles, but also improves the efficiency of methanol oxidation by constructing a new type of CQDs-Pt electrocatalyst. The composite material, which combines the dual function of photocatalysis and electrocatalysis will be a promising candidate for new photoelectrocatalytic fuel cells.

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“…QDs represents a more efficient solution with respect of dye sensitizers because of better stability and chemical compatibility with ZnO, tunable properties and dimensions by ease control of synthesis parameter and higher optical absorption. A great variety of semiconducting QDs like CdS, CdSe, CdTe, PbS, PbSe, CuInS 2 , Bi 2 S 3 , In 2 S 3 , and carbon QDs has been implemented in ZnO based photovoltaic cell to work in visible range and cover a larger adsorption spectrum. Functionalization of ZnO nanostructures with QDs can be classified in two groups depending on the particles growth approach.…”

Section: Surface‐engineering Of Zno Nanostructures With Nanoparticlesmentioning

confidence: 99%

Surface Engineering of Nanostructured ZnO Surfaces

Laurenti

Stassi

Canavese

et al. 2016

Adv Materials Inter

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are oriented in one direction and their assembly and stacking produces the wurtzite hexagonal symmetry. The noncentrosymmetric and anisotropic crystalline structure of wurtzite-like ZnO generates very interesting properties such as piezo-and pyro-electricity: the application of an external stimulus, like mechanical stress or temperature, deforms the tetrahedron structure. This deformation results in a separation between the positive and negative centers of charge, inducing the formation of a dipole moment. [7,8] The polar surface and anisotropic structure of ZnO can be usefully exploited to form different kinds of micro and nanostructures from 0D to 3D, [5] including, but not limited to nanowires, [9][10][11][12] nanotubes, [13,14] nanobelts, [15][16][17][18][19] nanorings, [20] flower-like morphologies, [21][22][23][24][25] multipods, [26,27] tetrapods, [28][29][30] sponge-like structures [31][32][33][34] and so on [29,[35][36][37][38][39] (Figure 1). Therefore, several research efforts have been invested in studying various preparation procedures for ZnO micro and nano-materials. Wet chemical approaches, like sol-gel, hydrothermal growths, electrodeposition and template-assisted routes, [40,41] as well as vapor-phase methods, for example chemical vapour deposition (CVD), physical vapour deposition (PVD) including sputtering and evaporation approaches, [42][43][44] and epitaxial growth methods [45] are among the most used ones. The great advantages of the wet chemical approaches are the high synthesis versatility, low temperature employed and low costs. [9] From the other side, dry methods take advantage of the high quality and excellent control over the level of crystallinity of the synthesized ZnO structures, as well as the absence of contamination and high purity of the final material. [46] The combination of different properties with the ease and high versatile synthesis of ZnO material in different micro and nanostructures offers a huge possibility of potential applications.For example, ZnO is already used as an efficient catalyst in the selective oxidation of involving oxygenates (i.e., alcohols, aldehydes, and carboxylic acids) and in methanol synthesis catalysts. It is also largely applied as protective, anti-corrosion layer in galvanized steel products, [49][50][51] as well as in paints and sunscreens as an UV absorber. Its biocompatibility makes this material suitable, in the form of microparticles, for paste formulations in cosmetic applications.The combination of the piezoelectric with the semiconducting properties of ZnO is found to result into new exciting physical properties, [52][53][54] and it has recently opened the research field to energy harvesting application. ZnO nanomaterials can be thus used as nanogenerators, able to convert the mechanical deformation from the surrounding environment into electrical Zinc Oxide (ZnO) nanostructures represent promising substrate materials for numerous applications, ranging from new generation solar cells, to bio-and chemical sensors. This interest is due ...

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H:ZnO Nanorod-Based Photoanode Sensitized by CdS and Carbon Quantum Dots for Photoelectrochemical Water Splitting

Cited by 66 publications

References 42 publications

Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Carbon quantum dot sensitized Pt@Bi₂WO₆/FTO electrodes for enhanced photoelectro-catalytic activity of methanol oxidation

Surface Engineering of Nanostructured ZnO Surfaces

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H:ZnO Nanorod-Based Photoanode Sensitized by CdS and Carbon Quantum Dots for Photoelectrochemical Water Splitting

Cited by 66 publications

References 42 publications

Fe2PO5‐Encapsulated Reverse Energetic ZnO/Fe2O3 Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Fe2PO5‐Encapsulated Reverse Energetic ZnO/Fe2O3 Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Carbon quantum dot sensitized Pt@Bi2WO6/FTO electrodes for enhanced photoelectro-catalytic activity of methanol oxidation

Surface Engineering of Nanostructured ZnO Surfaces

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Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Fe₂PO₅‐Encapsulated Reverse Energetic ZnO/Fe₂O₃ Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water

Carbon quantum dot sensitized Pt@Bi₂WO₆/FTO electrodes for enhanced photoelectro-catalytic activity of methanol oxidation