Danica Bajuk Bogdanović

Bio: Danica Bajuk Bogdanović is an academic researcher from University of Belgrade. The author has contributed to research in topics: Irradiation & Langmuir adsorption model. The author has an hindex of 4, co-authored 5 publications receiving 123 citations.

Surfactant-assisted microwave processing of ZnO particles: a simple way for designing the surface-to-bulk defect ratio and improving photo(electro)catalytic properties

Abstract: ZnO nanopowders were produced using microwave processing of a precipitate and applied as a photoanode for photoelectrochemical water splitting. Two different surfactants, cetyltrimethylammonium bromide (CTAB) as the cationic and Pluronic F127 as the non-ionic one, were employed to in situ adjust the surface-to-bulk defect ratio in the ZnO crystal structure and further to modify the photo(electro)catalytic activity of the ZnO photoanode. The crystal structure, morphological, textural, optical and photo(electro)catalytic properties of ZnO particles were studied in detail to explain the profound effects of the surfactants on the photoanode activity. The ZnO/CTAB photoanode displayed the highest photocurrent density of 27 mA g−1, compared to ZnO (10.4 mA g−1) and ZnO/F127 photoanodes (20 mA g−1) at 1.5 V vs. SCE in 0.1 M Na2SO4 under visible illumination of 90 mW cm−2. A significant shift of the overpotential toward lower values was also observed when photoanodes were illuminated. The highest shift of the overpotential, from 1.296 to 0.248 V vs. SCE, was recorded when the ZnO/CTAB photanode was illuminated. The ZnO/CTAB photoanode provides efficient charge transfer across the electrode/electrolyte interface, with a longer lifetime of photogenerated electron–hole pairs and reduced possibility of charge recombination. The photoconversion efficiency was improved from 1.4% for ZnO and 0.9% for ZnO/F127 to 4.2% for ZnO/CTAB at 0.510 mV. A simple procedure for the synthesis of ZnO particles with improved photo(electro)catalytic properties was established and it was found that even a small amount of CTAB used during processing of ZnO increases the surface-to-bulk defect ratio. Optimization of the surface-to-bulk defect ratio in ZnO materials enables increase of the absorption capacity for visible light, rendering of the recombination rate of the photogenerated pair, as well as increase of both the photocurrent density and photoconversion efficiency.

Detection of Dimethoate Pesticide using Layer by Layer Deposition of PDAC/GO on Ag electrode

Abstract: Dimethoate (DMT) is an organophosphate pesticide (OP), which is widely used against insects and mites and their control in agriculture. As other OPs, DMT is also an inhibitor of acetylcholinesterase, which is responsible for the disabling of cholinesterase required for the functioning of the central nervous system. This pesticide can invade living cells of the human body through contact or ingestion. We report an electrochemical sensor based on a layer by layer deposition of PDAC/GO on silver electrodes. The sensor fabrication, physical characterization i.e. Raman spectroscopy and scanning electron microscopy of PDAC/GO based films, and its electrochemical characterization are discussed. The detection of DMT by analyzing electrochemical measurements including cyclic voltammetry and impedance spectroscopy shows that functionalization using layer by layer deposition improves electrochemical response and presents a basis for detection of DMT. The highest response is observed in the case of only one PDAC/GO layer which is attributed to the properly balanced interaction between DMT and PDAC/GO layer, and the increase of electrical resistivity of the PDAC/GO layer with its thickness.