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•How to realize the electron-hole pair separation for photocatalysts?.•Properties and photocatalytic mechanisms of heterojunctions in all cases are discussed.•All types of the ...heterojunctions are expected to exhibit enhanced photocatalytic performances.
Construction of heterojunctions by coupling two semiconductors together is one of the most efficient ways to realize the electron-hole pair separation. In this short paper, I systematically discuss the properties of heterojunction photocatalysts in all cases. The formation of space charge regions, built-in electric field and potential barriers at the interface regions of thermally equilibrated heterojunctions are analyzed in details. When the heterojunctions are used for photocatalysis, the transfer behavior and mechanism of photo-excited non-equilibrium carriers between the constituent semiconductors are discussed. It is demonstrated that the heterojunction properties, carrier transfer behavior and photocatalytic mechanism depend highly on the semiconductivity (N-type or P-type), work function (or Fermi level), and CB/VB potentials of the constituent semiconductors. All types of the heterojunction photocatalysts are expected to exhibit enhanced photocatalytic performances. This paper provides an important insight into the understanding of heterojunction photocatalytic mechanism and design of excellent heterojunction composite photocatalysts.
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•G-C3N4/UiO-66 heterojunctions were synthesized by a facile one-pot method.•G-C3N4/UiO-66 nanohybrids were used as an visible-light-driven photocatalysts.•G-C3N4/UiO-66 nanohybrids ...enhanced the separation of photoexcited carriers.•G-C3N4/UiO-66 nanohybrids were stable even after the four cycles.
In this study, g-C3N4 nanosheets coated UiO-66 nanohybrids were fabricated via a simple solvothermal method. The physicochemical parameters, structural and electrochemical properties of g-C3N4/UiO-66 nanohybrids (CNUO-x) were investigated. The nanohybrids were systematically characterized by XRD, FT-IR, TGA, TEM, SEM, EDS elemental mappings, XPS, N2 adsorption-desorption isotherms, PL and DRS. It was found that the addition of moderate g-C3N4 could enhance the separation and migration rate of photo-induced charges, consequently leading to the increase of photocatalytic efficiency. The CNUO-1 nanohybrid exhibited better photocatalytic activity for the oxidation of Rh B under visible light irradiation, and displayed about 6.0 and 3.3 times faster than that of g-C3N4 and UiO-66, respectively. Meanwhile, the nanohybrid showed excellent stability and reusability in four cyclic experiments. Finally, the increased photocatalytic reaction mechanism was also proposed. O2−, h+ and OH were further found to be the main active contributors.
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•For the first time reporting the ZnO and Ag–ZnO Nps through solution combustion synthesis using succinic acid as low cost novel fuel.•Ag–ZnO Nps shows superior photocatalytic ...activity, antibacterial activity and biodiesel production compare to ZnO Nps.•ZnO and Ag–ZnO Nps has been used as a electrochemical interface to detect lead and cadmium metal ions simultaneously at nano concentration level.
Zinc oxide nanoparticles (ZnO Nps) and silver doped zinc oxide nanoparticles (Ag–ZnO Nps) were prepared using nitrates of zinc and silver as oxidizers and succinic acid as a fuel through solution combustion synthesis (SCS) at 400°C. The synthesized materials were characterized by various analytical techniques such as XRD, FTIR, Raman UV–vis, PL, SEM, EDX and TEM. The synthesized nanomaterials were tested for the photocatalytic degradation of methylene blue and the result reveal that Ag–ZnO Nps shows the better photocatalytic activity compared to undoped ZnO Nps. Biodiesel production from Simarouba oil shows that Ag–ZnO Nps acts as good catalyst compare to ZnO Nps, we have also developed sensor which showed a linearity in the concentration range 50–350nM and limit of detection was found to be 3.5 and 3.8nM (3σ) for lead and cadmium respectively. Further we have examined the antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria.
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