Improvement of g-C3N4 photocatalytic properties using the Hummers method

important practical value to prepare photocatalytic materials with high activity under visible light.Indium oxide (In 2 O 3 ), a n-type semiconductor material, has a direct band gap of 3.8 eV and an indirect band gap of 2.8 eV [2]. It is an effective sensitizer and its absorption spectrum can extend from ultraviolet region to the visible region. It has been widely used in solar cells [3], flat panel display [4], gas sensor [5]. However, due to the high electron-hole recombination rate, the efficiency of In 2 O 3 is still limited. In order to improve the photocatalytic activity of In 2 O 3 , researchers have used a variety of methods, such as morphology control [6,7], metal deposition [8], and combining with semiconductors [9][10][11].Graphitic carbon nitride (denoted as C 3 N 4 ) is a kind of medium band gap (2.7 eV) nonmetal photocatalyst [12]. It has good chemical stability and thermal stability. Furthermore, it can be used to split water into H 2 and O 2 and degrade organic pollutants under visible light irradiation [13]. But high photoproduction electron-hole recombination rate seriously affects the catalytic properties of C 3 N 4 . C 3 N 4 can be easily adhered on the surface of other compounds due to its softness. Deferent types of strategies have been used to make the catalytic properties of C 3 N 4 better, including coupling with metals [14][15][16] [29]. Compared with the original semiconductor materials, the photocatalytic performance of these composites were enhanced obviously. Through mechanism analyzing, the reason for photocatalytic performance enhancements may be the improvement of electron-hole migration and separation.Recently, some investigations about In 2 O 3 /C 3 N 4 were reported. In 2 O 3 /C 3 N 4 composites can be used for hydrogen evolution

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“…The estimated forbidden band width of In 2 O 3 and C 3 N 4 were 2.78 eV and 2.70 eV. The result was in agreement with the literature [41,42].…”

Section: Drs Analysissupporting

confidence: 91%

Ball-milling combined calcination synthesis of In2O3/C3N4 for high photocatalytic activity under visible light irradiation

Zhang

Huang

et al. 2017

J Mater Sci: Mater Electron

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“…[41,42] In recent years, many efficient methods have been applied for the modification of pristine bulk gC 3 N 4 , such as exfoliation into nanosheets, [43][44][45][46] structure defect engineering, [40,[47][48][49][50][51][52][53] sur face property modification, [54][55][56][57][58][59][60] crystal structure optimiza tion, [61] nanostructure construction, [62][63][64][65][66] and heterostructure formation. [69] The exfoliation of bulk gC 3 N 4 into monolayer or thinlayer gC 3 N 4 nanosheets has been successfully achieved by thermal oxidation exfoliation, [44] ultrasonic liquid exfoliation, [46] chem ical exfoliation, [70] and other methods. As inspired by the graphene exfoliated from graphite, delamination of bulk gC 3 N 4 into monolayer/thinlayer gC 3 N 4 is an effective strategy to improve the specific surface area, since the theoretical specific surface area of ideal monolayer gC 3 N 4 is as high as 2500 m 2 g −1 .…”

Section: Main Modification Strategies Of Pristine G-c 3 Nmentioning

confidence: 99%

g‐C₃N₄‐Based Heterostructured Photocatalysts

Wang

Jiang

et al. 2017

Advanced Energy Materials

2,169

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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“…The weak peak of O should come from citrate coated on the PdNPs surface. The C 1s XPS spectra displayed two peaks centered at 281.5 and 284.8 eV, was assigned to the graphitic carbon or sp2 CN and NCN inside the aromatic structure respectively . The N 1s spectra showed only a strong peak centered at 396.3 eV, which was identified as sp 2 ‐hybridized aromatic N bonded to C (NCN) in the triazine rings.…”

Section: Resultsmentioning

confidence: 99%

A Palladium‐Doped Graphitic Carbon Nitride Nanosheet with High Peroxidase‐Like Activity: Preparation, Characterization, and Application in Glucose Detection

Jin

Zhong

Chen

et al. 2017

Part & Part Syst Charact

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Herein, a novel palladium‐doped graphitic carbon nitride nanosheet (g‐C3N4‐PdNPs) is reported. The prepared g‐C3N4‐PdNPs has a 6.7 and 14.0 times higher peroxidase‐like activity in comparison with pure Pd nanoparticles (PdNPs) and graphitic carbon nitride (g‐C3N4) nanosheets respectively, and can be stably stored for 3 months. The high peroxidase‐like activity make g‐C3N4‐PdNPs effectively catalyze H2O2‐mediation oxidization of 3,3,5,5′‐tetramethylbenzidine to generate a color change from colorless to blue under lower concentration level and shorter time. The g‐C3N4‐PdNPs can be used as peroxidase mimetic to develop sensitive and specific colorimetric method for the rapid detection of glucose in the serum, and to fabricate a simple and cheap portable test kit for instrument‐free visual detection of glucose in serum. The portable test kit possesses obvious advantages such as low‐cost, short detection time, tiny sample consumption, excellent specificity, and higher visual sensitivity. The visual detection limit of portable test kit is lower than the glucose concentration in the serum of a diabetic. Using portable test kit, the glucose in serum can be visually detected by bare eye observation within 30 min with only 30 µL serum consumption. The success of this study provided a potential approach for low‐cost and instrument‐free “see” diabetes in clinical early diagnosis.

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Improvement of g-C3N4 photocatalytic properties using the Hummers method

Cited by 82 publications

References 35 publications

Ball-milling combined calcination synthesis of In2O3/C3N4 for high photocatalytic activity under visible light irradiation

Ball-milling combined calcination synthesis of In2O3/C3N4 for high photocatalytic activity under visible light irradiation

g‐C₃N₄‐Based Heterostructured Photocatalysts

A Palladium‐Doped Graphitic Carbon Nitride Nanosheet with High Peroxidase‐Like Activity: Preparation, Characterization, and Application in Glucose Detection

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Improvement of g-C3N4 photocatalytic properties using the Hummers method

Cited by 82 publications

References 35 publications

Ball-milling combined calcination synthesis of In2O3/C3N4 for high photocatalytic activity under visible light irradiation

Ball-milling combined calcination synthesis of In2O3/C3N4 for high photocatalytic activity under visible light irradiation

g‐C3N4‐Based Heterostructured Photocatalysts

A Palladium‐Doped Graphitic Carbon Nitride Nanosheet with High Peroxidase‐Like Activity: Preparation, Characterization, and Application in Glucose Detection

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g‐C₃N₄‐Based Heterostructured Photocatalysts