Fast Surface Charge Transfer with Reduced Band Gap Energy of FeVO4/Graphene Nanocomposite and Study of Its Electrochemical Property and Enhanced Photocatalytic Activity

2019 ◽  
Vol 44 (7) ◽  
pp. 6659-6667 ◽  
Author(s):  
Muhammad Munir Sajid ◽  
Naveed Akthar Shad ◽  
Yasir Javed ◽  
Sadaf Bashir Khan ◽  
Zahid Imran ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Surface Charge ◽  
Band Gap ◽  
Electrochemical Property ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Graphene Nanocomposite

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.

scholarly journals Polypyrrole-Bonded Quaternary Semiconductor LiCuMo2O11–Graphene Nanocomposite for a Narrow Band Gap Energy Effect and Its Gas-Sensing Performance

ACS Omega ◽  
2020 ◽  
Vol 5 (28) ◽  
pp. 17337-17346
Author(s):  
Won-Chun Oh ◽  
Kamrun Nahar Fatema ◽  
Yin Liu ◽  
Chong Hun Jung ◽  
Suresh Sagadevan ◽  
...  
Keyword(s):  
Band Gap ◽  
Gas Sensing ◽  
Narrow Band ◽  
Band Gap Energy ◽  
Energy Effect ◽  
Gap Energy ◽  
Graphene Nanocomposite ◽  
Sensing Performance

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.

scholarly journals Synthesis, characterization and photocatalytic activity of Zn2+, Mn2+ and Co2+ doped SnO2 nanoparticles

2019 ◽  
Vol 9 (5) ◽  
pp. 4199-4204 ◽  
Author(s):  
Oeindrila Mukhopadhyay ◽  
Soumita Dhole ◽  
Badal Kumar Mandal ◽  
Fazlur-Rahman Nawaz Khan ◽  
Yong-Chien Ling
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Transition Metal ◽  
Band Gap ◽  
Sno2 Nanoparticles ◽  
Transition Metal Ions ◽  
Band Gap Energy ◽  
Blue Dye ◽  
Gap Energy ◽  
Sno2 Nps

Nanomaterials with many improved properties have been used in versatile applications. Herein we have synthesized SnO2 NPs doped with transition metal ions such as Zn2+, Mn2+ and Co2+ through a facile and inexpensive hydrothermal approach. The synthesized nanomaterials were characterized by XRD, FT-IR, SEM and UV-Vis analysis. The optical properties of the NPs were characterized by using UV–vis and photoluminescence spectroscopy (PLS). Their photocatalytic performances were investigated by degrading methylene blue (MB) dye with UV irradiation. Transition metal doping to SnO2 NPs improved the photocatalytic activity to degradation of methylene blue dye due to tuning of band gap energy i.e. lowering of band gap energy compared to undoped SnO2 NPs. The results suggest that the synthesized NPs could be used efficiently for remediation/degradation of environmentally hazardous dyes from waste water or environmental cleanup.

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.

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%. 

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Sheikh Mohd Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%.

Photocatalytic Properties and Graphene Oxide Additional Effects in TiO2

2018 ◽  
Vol 280 ◽  
pp. 65-70
Author(s):  
N.A. Mohd Noor ◽  
S.K. Kamarudin ◽  
M. Darus ◽  
N.F. Diyana M. Yunos ◽  
M.A. Idris
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Band Gap ◽  
Uv Light ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Photodegradation Efficiency ◽  
Energy Conversation ◽  
Uv Light Irradiation ◽  
Promising Application

Photocatalytic activity in TiO2 attract great attention because it promising application in contaminations on degradation and energy conversation. However there is a need on TiO2 band gap modification to be equivalent with the visible light. Thus, inviting several method of addition certain elements including in this study, the additional of graphene oxide (GO) was investigated. GO were prepared by Hummer method before it was added into TiO2. The formation of GO from it graphite precursor had been confirmed by Raman spectroscopy. The existence of D-band at wavelength of 1328 cm-1 and G-band at 1573 cm-1 shows the formation of GO. The GO was then added in different concentration; 0.0 - 1.0 wt% into TiO2. The photocatalytic activity was determined using calculating the photodegradation efficiencies of methylene blue under UV light irradiation. The experimental results showed that the photodegradation of MB were increased with higher dopants concentration due to reduction of band gap energy of TiO2 from 3.2 eV to 3.0 eV for 1.0 wt% GO-with the photodegradation efficiency of GO doped TiO2 was 61.38%.

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