Electrochemically synthesized tungsten trioxide nanostructures for photoelectrochemical water splitting: Influence of heat treatment on physicochemical properties, photocurrent densities and electron shuttling

Zhu, Tao; Chong, Meng Nan; Phuan, Yi Wen; Chan, Eng Seng

doi:10.1016/j.colsurfa.2015.08.016

Cited by 23 publications

(14 citation statements)

References 27 publications

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“…Consequently, porous structures with a larger active surface area exhibit better photoelectrochemical performance due to a reduced rate of electron−hole recombination. Moreover, nanoporous oxide layers can release more photoinduced electron−hole pairs compared to compact materials [ 6 , 10 , 12 , 48 , 49 ]. It can explain a significantly worse photoresponse of sample G (more compact) compared to sample B (much more porous), while for both samples, the layer thickness and donor density are similar (see Figure 9 A).…”

Section: Discussionmentioning

confidence: 99%

Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions

2020

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Although anodic tungsten oxide has attracted increasing attention in recent years, there is still a lack of detailed studies on the photoelectrochemical (PEC) properties of such kind of materials grown in different electrolytes under various sets of conditions. In addition, the morphology of photoanode is not a single factor responsible for its PEC performance. Therefore, the attempt was to correlate different anodizing conditions (especially electrolyte composition) with the surface morphology, oxide thickness, semiconducting, and photoelectrochemical properties of anodized oxide layers. As expected, the surface morphology of WO3 depends strongly on anodizing conditions. Annealing of as-synthesized tungsten oxide layers at 500 °C for 2 h leads to obtaining a monoclinic WO3 phase in all cases. From the Mott-Schottky analysis, it has been confirmed that all as prepared anodic oxide samples are n-type semiconductors. Band gap energy values estimated from incident photon−to−current efficiency (IPCE) measurements neither differ significantly for as−synthesized WO3 layers nor depend on anodizing conditions such as electrolyte composition, time and applied potential. Although the estimated band gaps are similar, photoelectrochemical properties are different because of many different reasons, including the layer morphology (homogeneity, porosity, pore size, active surface area), oxide layer thickness, and semiconducting properties of the material, which depend on the electrolyte composition used for anodization.

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Section: Discussionmentioning

confidence: 99%

Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions

2020

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“…WO3 nanostructures (nanopores, nanorods/nanowires, nanoplatelets, etc.) have been synthesized by a number of different techniques such as hydrothermal methods [3,12,21], solvothermal methods [22,23], sol-gel [24,25], deposition processes (laser deposition [17], electrodeposition [1,[26][27][28][29][30][31][32], chemical vapor deposition [33], atomic layer deposition [14], RF sputtering [34], spin coating [35]), dry chemistry methods (plasma-assisted approach [36]) and anodization [1,6,7,15,37]. It is known that the chemistry of aqueous tungsten solutions is complex, since a wide variety of species can be obtained depending on many factors, such as the composition, the pH or the temperature of the solutions [38].…”

Section: Introductionmentioning

confidence: 99%

“…The formation of condensed isopolytungstates in acidic solutions and, especially, the interaction of WO3 with ligands or complexing agents (such as fluoride, hydrogen peroxide or polycarboxylic acids) can be used to customize WO3 nanostructures, thus providing a wide range of possibilities to obtain new morphologies and improved properties. Although the chemistry of tungsten species is incompletely understood, there is increasing interest in tungsten (VI) complexation for the fabrication of WO3 nanostructures [1,6,8,9,23,[28][29][30][31][32][39][40][41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

“…Concentrated H2O2-containing electrolytes (20-30 %) have been used to dissolve tungsten powders as a first step to obtain tungsten solutions which will act subsequently as precursors in the formation of WO3 nanostructures, mainly using electrodeposition techniques [29][30][31][32]. However, by using anodization in the presence of very low concentrations of H2O2 (lower than 0.5%), formation of WO3 nanostructures could be achieved in a simple and non-expensive single step, instead of using several stages involving different degrees of complexity and high amounts of H2O2.…”

Section: Introductionmentioning

confidence: 99%

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A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents

et al. 2017

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ElsevierFernández Domene, RM.; Sánchez Tovar, R.; Lucas-Granados, B.; Roselló-Márquez, G.; Garcia-Anton, J. (2017). A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents. (J. .The rich and complex chemistry of tungsten was employed to synthesize innovative WO3 nanoplatelets/nanosheets by simple anodization in acidic electrolytes containing different concentrations of complexing agents or ligands, namely Fand H2O2. The morphological and photoelectrochemical properties of these nanostructures were characterized. The best of these nanostructures generated stable photocurrent densities of ca. 1.8 mA cm -2 at relatively low bias potentials (for WO3) of 0.7 VAg/AgCl under simulated solar irradiation, which can be attributed to a very high active surface area.This work demonstrates that the morphology and dimensions of these nanostructures, as well as their photoelectrochemical behavior, can be controlled by adjusting the ligand concentration in the electrolytes, hence providing an easy and non-expensive route to fabricate and customize high-performance nanostructured photocatalysts for clean energy production and environmental applications.

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“…As the layers of WO3 contain a hydrated region, and therefore an amorphous structure, it must be transformed into a crystalline one to be used as electrochromic devices, in photoelectrochemical and photocatalytic processes, etc [16,17]. Heat treatment at high temperatures has been demonstrated to achieve that change, having a great influence on the morphology of the surface, on the crystal structure and on the phase transition [18,19].…”

Section: Introductionmentioning

confidence: 99%

Influence of annealing conditions on the photoelectrocatalytic performance of WO3 nanostructures

Roselló-Márquez

Fernández‐Domene

Sánchez-Tovar

et al. 2020

Separation and Purification Technology

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Electrochemically synthesized tungsten trioxide nanostructures for photoelectrochemical water splitting: Influence of heat treatment on physicochemical properties, photocurrent densities and electron shuttling

Cited by 23 publications

References 27 publications

Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions

Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions

A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents

Influence of annealing conditions on the photoelectrocatalytic performance of WO3 nanostructures

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