Dimer diamin içeren poliimid köpüklerin sentezi ve karakterizasyonu

Yapılan araştırmalara göre literatürde, yüksek termal kararlık ve yüksek mekanik dayanıklık gibi üstün özelliklere sahip ve biyobazlı poliimid köpük bulunmamaktadır. Bu tezde amacımız biyobazlı özelliği arttırılmış poliimid köpükler sentezi gerçekleştir

Electronic structure of ZnO(0001)/AgBr(111) heterojunction interface based on the TB-mBJ approximation

In this paper, we investigate the electronic structure of the ZnO and the AgBr semiconductors, in bulk and thin slab structures and in ZnO(0001)/AgBr(111) heterojunction interface, based on full-potential density functional theory and using the Tran and Blaha modified Beck Johnson potential. We obtain energy band gaps in excellent agreement with experiments. By analyzing the surface and interface states, it is found out that there is a wide two-dimensional n-type s-band at the surface of the nano-structures which grabs electrons from the bulk valence p–d band. The build-up potential at the interface is also determined which is 2.3 eV, higher at the AgBr side

ZnO/ZnBi2O4 nanocomposites with p-n heterojunction as durable visible-light-activated photocatalysts for efficient removal of organic pollutants

Novel ZnO/ZnBi2O4 nanocomposites were fabricated by integrating ZnO with ZnBi2O4 nanoparticles via a calcination process and the capability for photodegradation of diverse contaminants in aqueous solution was explored. Comprehensive morphological, structural, textural, optical, and photoelectrochemical characterization of the prepared samples were executed. The experimental results demonstrated that the as-fabricated heterojunctions can remarkably enhance photocatalytic ability for the degradation of RhB in comparison with the ZnO and ZnBi2O4 components. Furthermore, the optimized ZnO/ZnBi2O4 (10%) sample, with suitable photostability, represented great visible-light-induced photocatalytic efficiency towards the degradation of MB, fuchsine, and MO. The significantly boosted photocatalytic performance was associated with the enhanced visible-light spectral response, inhibited recombination of the charge carriers, and improved textural features, which verified by optical, photoelectrical, electrochemical impedance spectroscopy, and textural measurements. Besides, based on the formed p-n heterojunction between the components, the photocatalytic mechanism was discussed and the conceivable electrons/holes migration and separation pathways were also suggested. (C) 2020 Elsevier B.V. All rights reserved

Integration of BiOI and Ag3PO4 nanoparticles onto oxygen vacancy rich-TiO2 for efficient visible-light photocatalytic decontaminations

To develop an impressive photocatalyst for purification of environmental contaminants, BiOI and Ag3PO4 nanoparticles were adhered on the oxygen vacancy rich-TiO2 (denoted as TOx ) via a facile ultrasonic-assisted procedure to form TiO2-x/BiOI/Ag3PO4 (signify as TOx/BOI/APO) nanocomposites. Then, the physiochemical features of the nanocomposites were characterized via various techniques. It was discovered that the ternary photocatalyst with 10 wt% of APO demonstrates the greatest ability in elimination of RhB, which is almost 44.3, 4.12, and 2.18-folds premier than the bare TiO2, TOx, and TOx/BOI (20 %) materials, respectively. This excellent boosted photoability was ascribed to the p-n-n heterojunctions among the components, great visible-light absorption via BOI and APO semiconductors, and effective segregation of charges. An acceptable mechanism was also suggested through scavenging tests and the results of Mott-Schottky plots. This study displayed that the construction and rational design of p-n-n heterojunctions could be effective for extremely improving visible-light-induced photocatalytic performances for energy and environmental applications

Polyethylene glycol-doped BiZn2VO6 as a high efficiency solar-light-activated photocatalyst with substantial durability toward photodegradation of organic contaminations

In this study, we focus on a simple, low-priced, and mild condition hydrothermal route to construct BiZn2VO6 nanocompounds (NCs) as a novel photocatalyst with strong solar Eight absorption ability for environmental purification using solar energy. NCs were further doped with polyethylene glycol (PEG) to improve their photocatalytic efficiency for photodegradation processes through inhibition of fast charge carrier recombination rates and higher charge separation efficiency. Surface morphology, phase structure, optical characteristics, and band structure of the as-prepared samples were analyzed using XRD, EDX, XPS, SEM, UV-vis spectroscopy, CL, and BET techniques. PEG-doped BiZn2VO6 NCs were applied as effective materials to degrade various kinds of organic pollutants including cationic and anionic types, and these NCs exhibited excellent photocatalytic efficiency as compared to traditional photocatalysts. In particular, the PEG-doped BiZn2VO6 (0.10% w/v) photocatalyst exhibited highly enhanced photocatalytic performance with improvements of about 46.4, 28.3, and 7.23 folds compared with PEG-doped ZnO nanorods (NRs), pristine BiVO4, and BiZn2VO6 samples, respectively, for the decomposition of congo red (CR) dye. After 40 minutes of sunlight irradiation, 97.4% of CR was decomposed. In this study, scavenging experiments indicated that both hydroxyl radicals and holes play dominant roles in CR photodegradation under simulated solar Eight irradiation. Meanwhile, the optimal photocatalyst demonstrated good reproducibility and stability for successive cycles of photocatalysis.Funding Agencies|University of Mohaghegh Ardabili - Iran; Linkoping University - Sweden; AForsk [17-457]</p