scholarly journals Optimized Synthesis Temperature and Time to Obtain Crystalline Carbon Nitride with Enhanced Photocatalytic Activity for Phenol Degradation

2020 ◽  
Vol 20 (6) ◽  
pp. 1392
Author(s):  
Leny Yuliati ◽  
Mohd Hayrie Mohd Hatta ◽  
Siew Ling Lee ◽  
Hendrik Oktendy Lintang
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Carbon Nitride ◽  
Phenol Degradation ◽  
Synthesis Temperature ◽  
Band Gap Energy ◽  
Synthesis Time ◽  
Gap Energy

In this work, the crystalline carbon nitride photocatalysts were synthesized by an ionothermal technique with varied synthesis temperature of 500, 550, and 600 °C, and synthesis time of 2, 4, and 6 h. Fourier transform infrared spectra showed the successful formation of the prepared carbon nitrides from their characteristic vibration peaks. X-ray diffraction patterns suggested that the same phase of poly(triazine imide) and heptazine could be observed, but with different crystallinity. The optical properties showed that different temperatures and synthesis time resulted in the different band gap energy (2.72–3.02 eV) as well as the specific surface area (24–73 m2 g–1). The transmission electron microscopy image revealed that the crystalline carbon nitride has a near-hexagonal prismatic crystallite size of about 50 nm. Analysis by high-performance liquid chromatography showed that the best photocatalytic activity for phenol degradation under solar light simulator was obtained on the crystalline carbon nitride prepared at the 550 °C for 4 h, which would be due to the high crystallinity, suitable low band gap energy (2.82 eV), and large specific surface area (73 m2 g–1). Controlling both the temperature and synthesis time is shown to be important to obtain the best physicochemical properties leading to high activity.

Ultrasensitive reversible oxygen sensing by using liquid-exfoliated MoS2 nanoparticles

2016 ◽  
Vol 4 (16) ◽  
pp. 6070-6076 ◽  
Author(s):  
Yeon Hoo Kim ◽  
Kye Yeop Kim ◽  
You Rim Choi ◽  
Young-Seok Shim ◽  
Jong-Myeong Jeon ◽  
...  
Keyword(s):  
Specific Surface ◽  
Band Gap ◽  
Molybdenum Disulfide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Gas Sensors ◽  
Band Gap Energy ◽  
High Specific Surface Area ◽  
Two Dimensional ◽  
Gap Energy

Two-dimensional (2D) molybdenum disulfide (MoS2) has been attracting rapidly increasing interest for application in chemoresistive gas sensors owing to its moderate band gap energy and high specific surface area.

scholarly journals Novel Photocatalytic Nanocomposite Made of Polymeric Carbon Nitride and Metal Oxide Nanoparticles

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 874 ◽  
Author(s):  
Iwona Koltsov ◽  
Jacek Wojnarowicz ◽  
Piotr Nyga ◽  
Julita Smalc-Koziorowska ◽  
Svitlana Stelmakh ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Band Gap ◽  
Carbon Nitride ◽  
Rapid Heating ◽  
Metal Oxide Nanoparticles ◽  
Phenol Degradation ◽  
Oxide Nanoparticles ◽  
Simple Method ◽  
Polymeric Carbon

Semiconducting polymers are promising materials for photocatalysis, batteries, fuel applications, etc. One of the most useful photocatalysts is polymeric carbon nitride (PCN), which is usually produced during melamine condensation. In this work, a novel method of obtaining a PCN nanocomposite, in which PCN forms an amorphous layer coating on oxide nanoparticles, is presented. Microwave hydrothermal synthesis (MHS) was used to synthesize a homogeneous mixture of nanoparticles consisting of 80 wt.% AlOOH and 20 wt.% of ZrO2. The nanopowders were mechanically milled with melamine, and the mixture was annealed in the temperature range of 400–600 °C with rapid heating and cooling. The above procedure lowers PCN formation to 400 °C. The following nanocomposite properties were investigated: band gap, specific surface area, particle size, morphology, phase composition, chemical composition, and photocatalytic activity. The specific surface of the PCN nanocomposite was as high as 70 m2/g, and the optical band gap was 3 eV. High photocatalytic activity in phenol degradation was observed. The proposed simple method, as well as the low-cost preparation procedure, permits the exploitation of PCN as a polymer semiconductor photocatalytic material.

scholarly journals Synergistic Adsorption and Photocatalytic Activity under Visible Irradiation Using Ag-ZnO/GO Nanoparticles Derived at Low Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Viet Ha Tran Thi ◽  
The Ha Cao ◽  
Tri Nhut Pham ◽  
Tien Thanh Pham ◽  
Manh Cuong Le
Keyword(s):  
Photocatalytic Activity ◽  
Low Temperature ◽  
Visible Light ◽  
Band Gap ◽  
Surface Area ◽  
Irradiation Time ◽  
Removal Rate ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Visible Irradiation

Ag-ZnO/graphene oxide (AG-ZnO/GO) nanocomposite was synthesized via facile aqueous solution reactions at low temperature in order to improve the photocatalytic activity for cationic dye removal under visible light irradiation. Analytical techniques were carried out in order to determine the abilities including structure, state of elements, morphology, and surface area of synthesized materials. Ag-ZnO/GO nanocomposite presented an extremely high removal rate of methylene blue (MB) not only under UV light (over 99% removal) but also under visible light (85% removal) during the same irradiation time. In this study, initial process parameters of catalyst dosage, MB concentration, and pH of the solution were also examined for MB removal efficiency effects. The proposed mechanisms for the increased removal of MB by Ag-ZnO/GO nanocomposite under visible irradiation include increased photocatalytic degradation, mainly due to increased charge transfer capacity by lowering band gap energy; minimized recombination of the excited electron-hole pairs of ZnO with the addition of Ag into the ZnO crystal lattice; and an increased adsorption capacity with the addition of GO with high surface area and semiconductor function with zero band gap energy.

Effect of Anatase/Rutile Phase Ratio on the Photodegradation of Methylene Blue under UV Irradiation

2020 ◽  
Vol 998 ◽  
pp. 78-83
Author(s):  
Yi Yi Zaw ◽  
Du Ang Dao Channei ◽  
Thotsaphon Threrujirapapong ◽  
Wilawan Khanitchaidecha ◽  
Auppatham Nakaruk
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Calcination Temperature ◽  
Organic Compounds ◽  
Specific Surface Area ◽  
Uv Irradiation ◽  
Rutile Phase

Titanium dioxide (TiO2) is known as one of the widely used catalysts in photocatalysis process. Recently, the photocatalysis of TiO2 has been implied in water purification and treatment, particularly dyes and organic compounds degradations. Naturally, the TiO2 can be found in three phases including anatase, rutile and brookite; each phase has its own specific properties such as grain size, stability and band gap energy. In this work, the effect of calcination temperature on the structure, morphology and photocatalytic activity were investigated. The data suggested that the anatase/rutile ratio of TiO2 can be controlled through the calcination process. The phase transformation data strongly indicated the liner function between percentage of rutile phase and calcination temperature. The BET analysis provided the consistent data with XRD patterns by showing that the specific surface area was decreased by increasing calcination temperature. The photodegradation of methylene blue under UV irradiation proved that the mixed phase of anatase/rutile ratio at 78.5/21.5 provided the highest photocatalytic activity. The phase composition ratio can influence the nanoparticles properties including band gap, specific surface area and energy band structure. Therefore, the control of anatase/rutile ratio was an alternative to enhance the photocatalytic activity of TiO2 nanoparticles for dyes and organic compounds degradations.

scholarly journals Influencing Factors in the Synthesis of Photoactive Nanocomposites of ZnO/SiO2-Porous Heterostructures from Montmorillonite and the Study for Methyl Violet Photodegradation

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3427
Author(s):  
Is Fatimah ◽  
Gani Purwiandono ◽  
Putwi Widya Citradewi ◽  
Suresh Sagadevan ◽  
Won-Chun Oh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Band Gap ◽  
Degradation Mechanism ◽  
Methyl Violet ◽  
Band Gap Energy ◽  
Synthesis Methods ◽  
X Ray ◽  
Gap Energy ◽  
Zn Content

In this work, photoactive nanocomposites of ZnO/SiO2 porous heterostructures (PCHs) were prepared from montmorillonite clay. The effects of preparation methods and Zn content on the physicochemical features and photocatalytic properties were investigated. Briefly, a comparison of the use of hydrothermal and microwave-assisted methods was done. The Zn content was varied between 5 and 15 wt% and the characteristics of the nanomaterials were also examined. The physical and chemical properties of the materials were characterized using X-ray diffraction, diffuse-reflectance UV-Vis, X-ray photoelectron spectroscopy, and gas sorption analyses. The morphology of the synthesized materials was characterized through scanning electron microscopy and transmission electron microscopy. The photocatalytic performance of the prepared materials was quantified through the photocatalytic degradation of methyl violet (MV) under irradiation with UV and visible light. It was found that PCHs exhibit greatly improved physicochemical characteristics as photocatalysts, resulting in boosting photocatalytic activity for the degradation of MV. It was found that varied synthesis methods and Zn content strongly affected the specific surface area, pore distribution, and band gap energy of PCHs. In addition, the band gap energy was found to govern the photoactivity. Additionally, the surface parameters of the PCHs were found to contribute to the degradation mechanism. It was found that the prepared PCHs demonstrated excellent photocatalytic activity and reusability, as seen in the high degradation efficiency attained at high concentrations. No significant changes in activity were seen until five cycles of photodegradation were done.

Band Gap Narrowed P Doped 1T@2H MoS2 Nanosheets Towards Synergistically Enhanced Visible Light Photochemical Property

2020 ◽  
Vol 15 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Yipin Wang ◽  
Rongfang Zhang ◽  
Genliang Han ◽  
Xiaoping Gao
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Surface Area ◽  
Hydrothermal Process ◽  
Band Gap Energy ◽  
Commercial Application ◽  
Photochemical Property ◽  
Mos2 Nanosheets ◽  
Gap Energy

The weak transport charge efficiency and great band gap energy of layered MoS2 hamper its further commercial application. To overcome these deficiencies, we report a simple, controlled and handy hydrothermal process for realizing 2H MoS2 to 1T MoS2 transition with P source. Due to the more conductive ability and larger surface area, P-doped 1T@2H MoS2 nanosheets show an outstanding catalytic activity. Noticeably, P-doped 1T@2H MoS2 nanosheets with narrowed bandgap exhibits a remarkable optical photochemical performance. It fully eliminates 50 ml of 20 mg L–1 RhB in 70 minutes with outstanding recycling and structural stability by using 10 mg catalyst.

scholarly journals Dielectric, optical and enhanced photocatalytic properties of CuCrO2 nanoparticles

RSC Advances ◽  
2017 ◽  
Vol 7 (44) ◽  
pp. 27549-27557 ◽  
Author(s):  
Tokeer Ahmad ◽  
Ruby Phul ◽  
Parvez Alam ◽  
Irfan H. Lone ◽  
Mohd. Shahazad ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Band Gap ◽  
Surface Area ◽  
Band Gap Energy ◽  
Catalytic Degradation ◽  
Photocatalytic Properties ◽  
Sunlight Irradiation ◽  
Gap Energy ◽  
Precursor Route ◽  
Citrate Precursor

Delafossite CuCrO2 nanoparticles with band gap energy of 3.09 eV and surface area of 235 m2 g−1 were prepared by citrate precursor route showed enhanced catalytic degradation of methylene blue in H2O under the sunlight irradiation.

scholarly journals Photocatalytic Hydrogen Production from Water on Ga, Sn-Doped ZnS under Visible Light Irradiation

2014 ◽  
Vol 925 ◽  
pp. 200-204
Author(s):  
Leny Yuliati ◽  
Melody Kimi ◽  
Mustaffa Shamsuddin
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Production ◽  
Gap Energy

Zinc sulfide (ZnS) has been reported to act as a photocatalyts to reduce water to hydrogen. However, ZnS could not work under visible light irradiation due to its large band gap energy. In order to improve the performance of ZnS, Ga and Sn were doped to ZnS. The series of Ga (0.1),Sn (x)-ZnS with various amounts of Sn (x) was prepared by hydrothermal method. XRD patterns suggested that the addition of Ga might reduce the crystallinity of ZnS, suggesting that Ga might inhibit the crystal growth or agglomeration of ZnS. On the other hand addition of Sn did not much affect the structure of the Ga (0.1)-ZnS. The DR UU-visible spectra confirmed the red shift of the absorption edge with the addition of Ga due to the reduced band gap energy, while the addition of Sn did not much shift the absorption edge of the Ga (0.1)-ZnS to longer wavelength. FESEM images showed that all the prepared samples have sphere-shaped particles and no remarkable change was observed with the addition of Ga or Sn. The photocatalytic hydrogen production from water was carried out at room temperature in the presence of sacrificial agent under visible light irradiation. While ZnS did not show activity under visible light, all the prepared Ga (0.1)-ZnS and Ga (0.1),Sn (x)-ZnS samples exhibited photocatalytic activity for hydrogen production. The highest hydrogen production was achieved on Ga (0.1),Sn (0.01)-ZnS, which activity was ca. three times higher than that of the single doped Ga (0.1)-ZnS. This study clearly showed that Sn acted as a good co-dopant to increase the photocatalytic activity of Ga (0.1)-ZnS for hydrogen production from water under visible light irradiation.

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