Tuning the electronic and structural properties of WO3 nanocrystals by varying transition metal tungstate precursors

RSC Advances ◽  
2014 ◽  
Vol 4 (107) ◽  
pp. 62423-62429 ◽  
Author(s):  
Sara Rahimnejad ◽  
Jing Hui He ◽  
Wei Chen ◽  
Kai Wu ◽  
Guo Qin Xu
Keyword(s):  
Methylene Blue ◽  
Transition Metal ◽  
Oxygen Vacancy ◽  
Band Gap ◽  
Azo Dye ◽  
Electron Hole ◽  
Recombination Time ◽  
Metal Tungstate ◽  
Electronic And Structural Properties ◽  
Hole Recombination

WO3 nanoplates derived from NiWO4 were found to have the highest concentration of oxygen vacancy, narrowest band gap, longest electron–hole recombination time, and in turn the highest rate of photodegradation of azo dye methylene blue.

scholarly journals Synthesis of Heterostructure of ZnO@MOF-46(Zn) to Improve the Photocatalytic Performance in Methylene Blue Degradation

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1379
Author(s):  
Jiraporn Buasakun ◽  
Phakinee Srilaoong ◽  
Ramida Rattanakam ◽  
Tanwawan Duangthongyou
Keyword(s):  
Methylene Blue ◽  
Band Gap ◽  
Photocatalytic Performance ◽  
Degradation Process ◽  
Band Gap Energy ◽  
Photocatalytic Efficiency ◽  
Electron Hole ◽  
Methylene Blue Degradation ◽  
Gap Energy ◽  
Hole Recombination

The heterostructure of ZnO and MOF-46(Zn) was synthesized to improve the photocatalytic performance of ZnO and prove the synergistic theory that presented the coexistence of ZnO and MOF-46(Zn), providing better efficiency than pure ZnO. The heterostructure material was synthesized by using prepared ZnO as a Zn2+ source, which was reacted with 2-aminoterephthalic acid (2-ATP) as a ligand to cover the surface of ZnO with MOF-46(Zn). The ZnO reactant materials were modified by pyrolysis of various morphologies of IRMOF-3 (Zn-MOF) prepared by using CTAB as a morphology controller. The octahedral ZnO obtained at 150 mg of CTAB shows better efficiency for photodegradation, with 85.79% within 3 h and a band gap energy of 3.11 eV. It acts as a starting material for synthesis of ZnO@MOF-46(Zn). The ZnO/MOF-46(Zn) composite was further used as a photocatalyst material in the dye (methylene blue: MB) degradation process, and the performance was compared with that of pure prepared ZnO. The results show that the photocatalytic efficiency with 61.20% in the MB degradation of the heterostructure is higher than that of pure ZnO within 60 min (90.09% within 180 min). The reason for this result may be that the coexistence of ZnO and MOF-46(Zn) can absorb a larger range of energy and reduce the possibility of the electron–hole recombination process.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

Studies into the Yb-doping effects on photoelectrochemical properties of WO3 photocatalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (23) ◽  
pp. 19452-19458 ◽  
Author(s):  
Siao Li Liew ◽  
Gomathy Sandhya Subramanian ◽  
Chin Seng Chua ◽  
He-Kuan Luo
Keyword(s):  
Photoelectrochemical Properties ◽  
Electron Hole ◽  
Recombination Time ◽  
Doping Effects ◽  
Hole Recombination

Yb-doped WO3 photocatalysts are sub-stoichiometric WO3−x due to substitution of W6+ with Yb3+ cation, display shorter electron–hole recombination time and higher levels of donor densities, leading to higher and more stable photocurrent densities.

scholarly journals Photoelectrochemical and theoretical investigation of the photocatalytic activity of TiO2 : N

RSC Advances ◽  
2016 ◽  
Vol 6 (92) ◽  
pp. 89687-89698 ◽  
Author(s):  
Gabriela Byzynski Soares ◽  
Renan Augusto Pontes Ribeiro ◽  
Sergio Ricardo de Lazaro ◽  
Caue Ribeiro
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Effective Mass ◽  
Theoretical Investigation ◽  
Hole Pair ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
N Doping ◽  
Hole Recombination

In N-doping on TiO2 nanomaterial occurs a big decrease of band-gap (1 eV); however, its photocatalysis is low. We clarify such fact from effective mass, i.e., the electron–hole recombination is more than creation of electron–hole pair.

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.

Electron–Hole Recombination Time at TiO2 Single-Crystal Surfaces: Influence of Surface Band Bending

2014 ◽  
Vol 5 (11) ◽  
pp. 1953-1957 ◽  
Author(s):  
Kenichi Ozawa ◽  
Masato Emori ◽  
Susumu Yamamoto ◽  
Ryu Yukawa ◽  
Shingo Yamamoto ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Surfaces ◽  
Electron Hole ◽  
Surface Band ◽  
Band Bending ◽  
Single Crystal Surfaces ◽  
Recombination Time ◽  
Hole Recombination
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