Visible-light-responsive bicrystalline (anatase/brookite) nanoporous nitrogen-doped TiO2 photocatalysts by plasma treatment

Lee, Hyun Uk; Lee, Young-Chul; Lee, Soon Chang; Park, So Young; Son, Byoungchul; Lee, Jae Won; Lim, Chang–Hyun; Choi, Chel‐Jong; Choi, Moon‐Hee; Lee, So Yeun; Oh, You-Kwan; Lee, Jun Young

doi:10.1016/j.cej.2014.06.011

Cited by 42 publications

(18 citation statements)

References 45 publications

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“…Furthermore, a recent study 43 found that mixed anatase/brookite samples showed reduced photoluminescence in comparison to the pure phases, indicating increased charge separation. Again, this result would follow from our calculated band alignment.…”

Section: Applications Photoelectrochemical Water Splittingmentioning

confidence: 99%

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

et al. 2015

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We report that the valence and conduction band energies of TiO 2 can be tuned over a 4 eV range by varying the local coordination environments of Ti and O. We examine the electronic structure of eight known polymorphs and align their ionization potential and electron affinity relative to an absolute energy reference, using an accurate multi-scale quantum-chemical approach. For applications in photocatalysis, we identify the optimal combination of phases to enhance activity in the visible spectrum. The results provide a coherent explanation for a wide range of phenomena, including the performance of TiO 2 as an anode material for Li-ion batteries, allow us to pinpoint hollandite TiO 2 as a new candidate transparent conducting oxide, and serve as a guide to improving the efficiency of photoelectrochemical water splitting through polymorph engineering of TiO 2 .

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Section: Applications Photoelectrochemical Water Splittingmentioning

confidence: 99%

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

et al. 2015

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“…Generally, a semiconductor catalyst with large specific surface area is beneficial for efficient photocatalysis, while in most synthetic processes, TiO 2 with the brookite phase or a mixture of TiO 2 polymorphs obtained hydrothermally at high temperature and with long time heat treatment have low surface area [14,19,23,24]. Hence, it is challenging to synthesize N-doped anatase/brookite TiO 2 photocatalyst with large surface area and enhanced visible light activity at low temperature via simple and direct synthetic method.…”

Section: Introductionmentioning

confidence: 99%

“…If low heating temperature in the range of 180-200 • C was employed in hydrothermal or solvothermal method, longer time (3-48 h) would be needed. Nevertheless, the obtained TiO 2 samples still have low surface area (<125 m 2 /g) [18,21,23]. Moreover, a supercritical drying process was often used in the conventional Catalysts 2017, 7, 376 3 of 10 sol-gel method [28].…”

Section: Syntheses and Characterizationsmentioning

confidence: 99%

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Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance

Jiang

Yang

et al. 2017

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Nitrogen doping in combination with the brookite phase or a mixture of TiO 2 polymorphs nanomaterials can enhance photocatalytic activity under visible light. Generally, nitrogendopedanatase/brookite mixed phases TiO 2 nanoparticles obtained by hydrothermal or solvothermal method need to be at high temperature and with long time heating treatment. Furthermore, the surface areas of them are low (<125 m 2 /g). There is hardly a report on the simple and direct preparation of N-doped anatase/brookite mixed phase TiO 2 nanostructures using sol-gel method at low heating temperature. In this paper, the nitrogen-doped anatase/brookite biphasic nanoparticles with large surface area (240 m 2 /g) were successfully prepared using sol-gel method at low temperature (165 • C), and with short heating time (4 h) under autogenous pressure. The obtained sample without subsequent annealing at elevated temperatures showed enhanced photocatalytic efficiency for the degradation of methyl orange (MO) with 4.2-, 9.6-, and 7.5-fold visible light activities compared to P25 and the amorphous samples heated in muffle furnace with air or in tube furnace with a flow of nitrogen at 165 • C, respectively. This result was attributed to the synergistic effects of nitrogen doping, mixed crystalline phases, and high surface area.

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“…Hydrogen, boron, carbon, nitrogen, fluorine, iodine, sulfur, and phosphorus have been used in this capacity, but nitrogen has been studied most extensively. Until now, various approaches to incorporate nitrogen atoms into titania have been reported, such as doping during film sputtering [131], annealing under ammonia gas [12], ion implantation [132,133], hydrazine treatment [134][135][136], urea treatment [137][138][139], treatment of sol-gel titania with nitrogen-containing organics [140], electrochemical processing [141], chemical vapor deposition [142], and plasma techniques [11,13,35,[143][144][145][146][147][148][149][150]. Most of the above doping methods require high temperature treatment and complicated or expensive equipment.…”

Section: Nitrogen Dopingmentioning

confidence: 99%

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

et al. 2017

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Mesoporous titania (mp-TiO 2 ) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO 2 . However, because the large band gap of TiO 2 limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO 2 . While first-principles calculations support the efficacy of this approach, it is challenging to efficiently introduce active non-metal dopants into the lattice of TiO 2 . This review surveys recent advances in the preparation of mp-TiO 2 and their doping with non-metal atoms. Different doping strategies and dopant sources are discussed. Further, co-doping with combinations of non-metal dopants are discussed as strategies to reduce the band gap, improve photogenerated charge separation, and enhance visible light absorption. The improvements resulting from each doping strategy are discussed in light of potential changes in mesoporous architecture, dopant composition and chemical state, extent of band gap reduction, and improvement in photocatalytic activities. Finally, potential applications of non-metal-doped mp-TiO 2 are explored in water splitting, CO 2 reduction, and environmental remediation with visible light.

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Visible-light-responsive bicrystalline (anatase/brookite) nanoporous nitrogen-doped TiO2 photocatalysts by plasma treatment

Cited by 42 publications

References 45 publications

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

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Visible-light-responsive bicrystalline (anatase/brookite) nanoporous nitrogen-doped TiO2 photocatalysts by plasma treatment

Cited by 42 publications

References 45 publications

Polymorph Engineering of TiO2: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Polymorph Engineering of TiO2: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

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Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination