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Design & Synthesis of ZnO-based Composite Nanofiber Photocatalysts with Z-Scheme Structure for Degradation of Organic Pollutants
, Ph.D. Dissertation Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Pourjavadi, Ali (Supervisor) ; Mahmoodi, Niaz Mohammad (Co-Supervisor)
Abstract
The aim of conducting this research is to study, fabrication and photocatalytic application of electrospun ZnO-based composite nanofibers. One of the most important challenges is to apply photocatalyst under solar irradiation and improve its activity for pollutant degradation. ZnO is a wide band gap semiconductor, hence, it is not active under the visible light. In Iran, we have at least 300 sunny days in a year. Therefore, fabrication and application of photocatalytic material with activity under the sunlight which contains 47% of visible light is so vital in our country. Since CuO is a visible light active photocatalyst and its interface with ZnO forms a type I heterojunction, this...
Enhanced spatially coupling heterojunction assembled from CuCo2S4 yolk-shell hollow sphere capsulated by Bi-modified TiO2 for highly efficient CO2 photoreduction
, Article Chemical Engineering Journal ; Volume 444 , 2022 ; 13858947 (ISSN) ; Zehtab Salmasi, M ; Moradi, M ; Farshineh Saei, S ; Kakavandi, B ; Rahman Setayesh, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The metal sulfides with highly negative reduction potential and long life-span of photocreated electrons are conducive to being exceptional candidates for CO2 photoreduction, whereas they suffer from self-photo-oxidation (or photocorrosion) that puts the greatest impediment to their practical application. Up to now, the Z-type strategy is stated as a favorable solution to overtake photocorrosion of metal sulfides, while the eligible choice for coupling with these materials is still challenging. TiO2 with more negative onset potential holds favorable inherent peculiarities over other materials, which produces overlapped potential with various ranges of metal sulfides. In this investigation,...
Improved solar-driven photocatalytic activity of hybrid graphene quantum dots/ZnO nanowires: a direct Z-scheme mechanism
, Article ACS Sustainable Chemistry and Engineering ; Volume 5, Issue 1 , 2017 , Pages 367-375 ; 21680485 (ISSN) ; Samadi, M ; Yousefzadeh, S ; Soltani, M ; Rahimi, A ; Chou, T. C ; Chen, L. C ; Chen, K. H ; Moshfegh, A. Z ; Sharif University of Technology
Abstract
Herein, an electrochemical technique as a cost-effective and one-step approach was utilized to fabricate graphene quantum dots (GQDs). Different amounts of GQDs (0, 0.2, 0.4, 0.8, and 1.2 wt %) were decorated uniformly on the surface of anodized ZnO nanowires (NWs) forming GQD/ZnO NWs. Transmission electron microscopy and atomic force microscopy confirmed formation of GQDs on the ZnO NWs, 12-22 nm in width and 1-3 graphene layers thick. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were employed to verify the functional groups on the surface of GQDs, and the results indicated that GQDs readily anchored on the surface of ZnO NWs. The GQD/ZnO NWs exhibited a...