A unique Z-scheme 2D/2D nanosheet heterojunction design to harness charge transfer for photocatalysis

Cheng, Huijie; Hou, Jungang; Takeda, Osamu; Guo, Xing‐Min; Zhu, Hongmin

doi:10.1039/c5ta01864a

Cited by 120 publications

(61 citation statements)

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“…The electrons will flow from gC 3 N 4 to TiO 2 until the Fermi level equilibrium, resulting in the TiO 2 surface being negatively charged and the gC 3 N 4 surface being posi tively charged. [151] A unique Zscheme 2D/2D gC 3 N 4 /Bi 20 TiO 32 (CN/BTO) heterojunction was reported by Cheng et al [173] Quantum dots have been widely applied in photocatalysis due to the decrease in charge carrier recombination resulting from shorter average diffusion distance from the inte rior to the surface. As a result, a builtin electric field will form at the interface of gC 3 2D/2D heterojunctions with large face toface contact area should be beneficial to more efficient interfacial charge transfer.…”

Section: Wwwadvancedsciencenewscommentioning

confidence: 99%

g‐C₃N₄‐Based Heterostructured Photocatalysts

Wang

Jiang

et al. 2017

Advanced Energy Materials

2,111

937

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Thereafter, the photocatalytic degrada tion of polychlorobiphenyls [2] and photo electrocatalytic reduction of CO 2 into hydrocarbon compounds [3] in aqueous semiconductor suspensions greatly broad ened the applications of photocatalysis. Although the photocatalytic technology has got worldwide attention for its eco nomic, clean, safe, and renewable charac teristics, the photocatalytic performance of currently known photocatalysts is still far from commercial applications, especially in solartofuel conversion. [4][5][6][7][8][9][10][11] Generally, the photocatalytic reactions can be divided into three basic processes. First, the semiconductor photocatalysts absorb effective photons whose energy (h v ) is equal to or above their bandgap (E g ), resulting in the generation of electronhole pairs. Second, the photogenerated charge carriers separate and transfer to the surface of photocatalysts. Third, the photogenerated electrons and holes partic ipate in reactions of substances adsorbed on the surface of the photocatalysts. [12,13] Thus, the improvements of the three aforementioned processes play impor tant roles in enhancing the photocatalytic performance. Light absorption is the first essential step of photocatalysis process. The traditional anatase phase TiO 2 photocatalyst is active only under UV light with wavelength below 387 nm due to its wide bandgap (3.2 eV). However, solar energy is mainly concentrated in the visible light region, and UV light accounts for less than 4% of the solar spectrum. [7] In order to achieve maximum utilization efficiency of solar energy, the exploration of visiblelightresponsive photo catalysts is an urgent task. Graphitic carbon nitride (gC 3 N 4 ) as a promising visiblelightresponsive photocatalyst has received worldwide attention due to its fascinating merits, such as moderate bandgap (≈2.7 eV), proper electronic band structure, nontoxicity, low cost, good stability, and easy preparation. [14][15][16][17][18] Since the first report on photocatalytic H 2 evolution over gC 3 N 4 by Wang et al. in 2009, [19] research endeavors toward improving the photocatalytic performance of gC 3 N 4 based photocatalysts have formed a forefront of photocatalysis research. [20][21][22][23][24][25] Bulk gC 3 N 4 powder can be prepared by the thermal poly condensation of lowcost nitrogencontaining organic pre cursors, e.g., urea, thiourea, melamine, cyanamide, dicyan diamide, guanidine hydrochloride, and so on. [26][27][28][29][30][31][32] The pure bulk gC 3 N 4 prepared by this method suffers from several shortcomings, including low specific surface area, insufficient visible light utilization, and, particularly, rapid recombination Photocatalysis is considered as one of the promising routes to solve the energy and environmental crises by utilizing solar energy. Graphitic carbon nitride (g-C 3 N 4 ) has attracted worldwide attention due to its visible-light activity, facile synthesis from low-cost materials, chemical stability, and unique layered structure. However, the pure g-C 3 N 4 photocatalys...

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Section: Wwwadvancedsciencenewscommentioning

confidence: 99%

g‐C₃N₄‐Based Heterostructured Photocatalysts

Wang

Jiang

et al. 2017

Advanced Energy Materials

2,111

937

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“…The plant photosynthesis involves a Z‐scheme system with two photon processes of photosystems PS I and PS II. Although many semiconductor‐based Z‐scheme photocatalysts for water splitting need an electron mediator playing a crucial role in shuttling photogenerated electron between the H 2 ‐ and O 2 ‐generating photocatalysts, recently Z‐scheme photocatalysts without an electron mediator, i.e., direct Z‐scheme system (Figure d), have also been developed . As shown in Figure e, the intervention of a highly conductive nanosheet prevents the electron–hole recombination because this nanosheet attracts photogenerated charge species from the surrounding material by acting as a charge reservoir.…”

Section: Introductionmentioning

confidence: 99%

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

2018

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Inorganic 2D nanosheets are important building blocks for synthesizing efficient hybrid photocatalysts because of their advantageous characteristics such as highly anisotropic 2D morphology with subnanometer-level thickness, wide surface area, defect-free tunable surface, chemical composition diversity and crystal structure, and tailorable physicochemical properties. Since most of the components in exfoliated nanosheets are exposed on the surface, an unusually strong chemical interaction and a remarkable electronic coupling can occur in the interface between the exfoliated nanosheets and hybridized nanospecies. Such strong electronic coupling is useful in optimizing the photocatalytic activity of the hybrid material via the suppression of electron-hole recombination, increase of the light absorption region, improved transport of excited charge carriers, and increase of surface reactivity. Herein, several representative examples of inorganic 2D nanosheetbased hybrid photocatalysts are introduced to examine the crucial role of 2D nanosheets in the enhancement of the photocatalytic activity of the hybrid materials. Special emphasis is made regarding the unique hybridization effect of exfoliated 2D nanosheets on the optical properties and electron structure of semiconducting species. Future perspectives for the investigation of the 2D nanosheet-based hybrids are discussed to provide valuable insight for the design and synthesis of highly efficient photocatalysts for producing solar fuels.

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“…From Fig. 3(d), the asymmetrical O 1 s peak can be deconvoluted into two peaks located at 530.0 and 530.9 eV, which are ascribed to the oxygen ions in the fully oxidized surrounding and the oxygen ions in oxygen deficient regions, respectively [16]. As displayed in Fig.…”

Section: Photocatalytic Activitymentioning

confidence: 91%

Novel MoS 2 -modified AgVO 3 composites with remarkably enhanced photocatalytic activity under visible-light irradiation

Cao

2017

Materials Letters

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A unique Z-scheme 2D/2D nanosheet heterojunction design to harness charge transfer for photocatalysis

Abstract: This work will shed light on the rational design of more complex 2D/2D heterojunctions with the Z-scheme energy-transfer mechanism.

Cited by 120 publications

References 40 publications

g‐C₃N₄‐Based Heterostructured Photocatalysts

g‐C₃N₄‐Based Heterostructured Photocatalysts

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

Novel MoS 2 -modified AgVO 3 composites with remarkably enhanced photocatalytic activity under visible-light irradiation

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A unique Z-scheme 2D/2D nanosheet heterojunction design to harness charge transfer for photocatalysis

Abstract: This work will shed light on the rational design of more complex 2D/2D heterojunctions with the Z-scheme energy-transfer mechanism.

Cited by 120 publications

References 40 publications

g‐C3N4‐Based Heterostructured Photocatalysts

g‐C3N4‐Based Heterostructured Photocatalysts

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

Novel MoS 2 -modified AgVO 3 composites with remarkably enhanced photocatalytic activity under visible-light irradiation

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Product

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g‐C₃N₄‐Based Heterostructured Photocatalysts

g‐C₃N₄‐Based Heterostructured Photocatalysts