Novel composite ZnO/TiO2 thin film photoanodes for enhanced visible-light-driven photoelectrochemical water splitting activity

Sreedhar, Adem; Jung, Hahn Chul; Kwon, Jin Hyuk; Yi, Jonghoon; Sohn, Youngku; Gwag, Jin Seog

doi:10.1016/j.jelechem.2017.09.045

Cited by 41 publications

(19 citation statements)

References 26 publications

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“…Additionally, eximious interconnectivity was present throughout the structure, yielding better light absorption efficiency (as evidenced by UV-Vis spectroscopy) due to the high surface area and small particle size of the spherical nanograins [106]. The excellent interparticle connectivity improved the conductance of the photogenerated electrons to the FTO contact surface [99]. A cross sectional side view of bare FTO is shown in Figure 8C.…”

Section: Morphological Analysismentioning

confidence: 99%

Investigation and Optimization of Mxene Functionalized Mesoporous Titania Films as Efficient Photoelectrodes

Iqbal

Hamdan

2021

Materials

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Three-dimensional mesoporous TiO2 scaffolds of anatase phase possess inherent eximious optical behavior that is beneficial for photoelectrodes used for solar energy conversion applications. In this regard; substantial efforts have been devoted to maximizing the UV and/or visible light absorption efficiency; and suppressing the annihilation of photogenerated charged species; in pristine mesoporous TiO2 structures for improved solar illumination conversion efficiency. This study provides fundamental insights into the use of Mxene functionalized mesoporous TiO2 as a photoelectrode. This novel combination of Mxene functionalized TiO2 electrodes with and without TiCl4 treatment was successfully optimized to intensify the process of photon absorption; charge segregation and photocurrent; resulting in superior photoelectrode performance. The photocurrent measurements of the prepared photoelectrodes were significantly enhanced with increased contents of Mxene due to improved absorption efficiency within the visible region; as verified by UV–Vis absorption spectroscopy. The anatase phase of TiO2 was significantly augmented due to increased contents of Mxene and postdeposition heat treatments; as evidenced by structural analysis. Consequently; an appreciable coverage of well-developed grains on the FTO surface was observed in SEM images. As such; these newly fabricated conductive mesoporous TiO2 photoelectrodes are potential candidates for photoinduced energy conversion and storage applications.

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Section: Morphological Analysismentioning

confidence: 99%

Investigation and Optimization of Mxene Functionalized Mesoporous Titania Films as Efficient Photoelectrodes

Iqbal

Hamdan

2021

Materials

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“…With rapid progress in nanoscience and nanotechnology, photocatalysts that utilize light-assisted catalytic reactions have played a crucial role in removing these toxic pollutants [11,12]. In particular, the removal of organic contaminants in wastewater has been both promising and challenging.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the removal of organic contaminants in wastewater has been both promising and challenging. To improve the photocatalytic performance, a variety of oxide semiconductors such as ZnO, g-C 3 N 4 , CdS, and TiO 2 have been extensively investigated based on their chemical stability, wide bandgap, and cost-effectiveness [12][13][14][15][16][17]. However, these oxide semiconductors suffered from photo corrosion and high carrier recombination rates [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Rice Crust-Like ZnO/Ti3C2Tx MXene Hybrid Structures for Improved Photocatalytic Activity

Tran

Noh

2020

Catalysts

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Novel two-dimensional ZnO/Ti3C2Tx hybrid photocatalysts with modified surface areas were prepared using a simple calcination technique. The microstructures, crystalline features, and bonding states of the ZnO structure-covered Ti3C2Tx MXenes were closely characterized using various tools. The photoluminescence intensity of the hybrid photocatalyst was greatly reduced compared to the pristine ZnO, while its Brunauer-Emmett-Teller (BET) surface area increased by more than 100 times. Under solar light illumination, the photocatalytic degradation efficiency of the hybrid photocatalyst for organic pollutants (MO, RhB) appeared to be three-fold larger as compared to pristine ZnO. The superb photocatalytic performance of the photocatalyst was attributed to several factors, such as ideal band alignment, Schottky barrier formation, and large surface area. Moreover, the ZnO/Ti3C2Tx hybrid photocatalyst showed excellent cycling stability. These results suggest that the novel hybrid structure may be a potential candidate for removing organic pollutants in wastewater.

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“…To overcome these drawbacks, doping of these materials with small amounts of anion or cation species, as well as the formation of nano-heterojunctions with other appropriate oxide materials, were proposed as the main approaches [ 17 , 18 ]. Loading of the TiO 2 nanotube surface with ultrathin oxide layers or nanoparticles may result in the formation of semiconductor heterojunctions, which enhances the spatial separation of electron-hole pairs, thus reducing the recombination rate [ 17 , 19 , 20 , 21 , 22 ]. Several methods for ZnO/TiO 2 heterojunctions fabrication were reported, such as: (a) formation of ZnO-TiO 2 nanocomposite arrays on Ti fabric using hydrothermal process [ 20 ]; (b) decorating of TiO 2 nanotube surface with nano-rice-shaped ZnO using chemical bath deposition [ 23 ]; (c) growth of ZnO nanostructures on top of TiO 2 nanotubes via electrochemical method [ 24 , 25 ] or dip coating [ 26 ]; and (d) deposition of heterojunction of ZnO on hydrogenated TiO 2 nanotube arrays by atomic layer deposition (ALD) [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Surface Wettability of ZnO-Loaded TiO2 Nanotube Array Layers

et al. 2020

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Herein we report on the synthesis and the effects of gradual loading of TiO2 nanotube array layers with ZnO upon surface wettability. Two-step preparation was chosen, where TiO2 nanotube layers, grown in a first instance by anodization of a Ti foil, were gradually loaded with controlled amounts of ZnO using the reactive RF magnetron sputtering. After crystallization annealing, the formerly amorphous TiO2 nanotubes were converted to predominantly anatase crystalline phase, as detected by XRD measurements. The as-prepared nanotubes exhibited a well-aligned columnar structure, 1.6 μm long and 88 nm in diameter, and a small concentration of oxygen vacancies. Ti2+ and Ti3+ occur along with the Ti4+ state upon sputter-cleaning the layer surfaces from contaminants. The Ti2+ and Ti3+ signals diminish with gradual ZnO loading. As demonstrated by the VB-XPS data, the ZnO loading is accompanied by a slight narrowing of the band gap of the materials. A combined effect of material modification and surface roughness was taken into consideration to explain the evolution of surface super-hydrophilicity of the materials under UV irradiation. The loading process resulted in increasing surface wettability with approx. 33%, and in a drastic extension of activation decay, which clearly points out to the effect of ZnO-TiO2 heterojunctions.

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Novel composite ZnO/TiO2 thin film photoanodes for enhanced visible-light-driven photoelectrochemical water splitting activity

Cited by 41 publications

References 26 publications

Investigation and Optimization of Mxene Functionalized Mesoporous Titania Films as Efficient Photoelectrodes

Investigation and Optimization of Mxene Functionalized Mesoporous Titania Films as Efficient Photoelectrodes

Rice Crust-Like ZnO/Ti3C2Tx MXene Hybrid Structures for Improved Photocatalytic Activity

Surface Wettability of ZnO-Loaded TiO2 Nanotube Array Layers

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