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Three zeolites (A, X and Y) with Ag incorporated in their cages are tested as bifunctional electrocatalysts for direct borohydride fuel cells (DBFCs). Ag zeolites are characterised by XRD, FTIR, nitrogen sorption and SEM, as well as by electrochemical methods. Ag zeolite shows good activity for the anodic reaction, i.e., borohydride oxidation reaction (BOR) in alkaline media, presenting low onset potential and high current densities. BOR kinetic and faradaic parameters at AgY are calculated, with the number of exchanged electrons being 4.3. The BOR at AgY was found to be of 0.6 order with respect to BH4 concentration with an activation energy of 13 kJ mol 1. Regarding ORR, AgX shows the best performance with the highest current densities and good stability over time. A two-electron pathway is observed for ORR at AgX and specific capacitance was calculated to be 5.61 F g 1. The DBFC performance is investigated based on half-cell measurements of the AgY anode and Pt/C cathode

This work shows the potential application of carbon materials prepared by three different ionic liquid-based methods, using 1-butyl-3-methylimidazolium methanesulfonate [bmim][MeSO3], for electrochemical supercapacitors. The effects of [bmim][MeSO3] on morphology, texture and surface chemistry of prepared materials has been explored by SEM/TEM, N2/CO2 adsorption measurements and XPS. The results indicate the possibility of synthesis of carbon materials with tunable physicochemical properties using ionic liquid based methods. The charge storage behavior of all materials was studied in three different pH aqueous electrolytes. The pseudocapacitive and double layer contributions were estimated and discussed from the aspect of the textural changes and the changes of the chemical composition of surface functional groups containing heteroatoms. C[dbnd]O type functional groups, with the contribution of COOH groups, were found to be responsible for a different amount of charge, which could be stored in alkaline and acidic electrolytic solution. The material prepared by direct carbonization of [bmim][MeSO3], showed the best electrochemical performance in alkaline electrolyte with a capacitance of 187 F g−1 at 5 mV s−1 (or 148 F g−1 at 1 A g−1), due to the contribution of both electric-double layer capacitance and pseudocapacitance which arises from oxygen, nitrogen and sulfur functional groups.

У складу са чињеницом да се све више пажње посвећује коришћењу обновљивих извора енергије, па тако и могућностима употребе дрвне биомасе као еколошки прихватљивом гориву, али и ресурсу који може бити употребљен у другим индустријама (индустрија целулозе и папира, индустрија плоча и иверица), у овом раду је истражен производни потенцијал дрвне биомасе (дрвне сечке) и његов утицај на циљеве газдовања шумама у Јужнобачком шумском подручју. У раду су испитани механизми припреме и доношења одлука, који подразумевају „анализу предузећа“ и „анализу окружења“ уз укључивање интересних група и усклађивање потреба и визија са могућностима производње дрвне биомасе. Доношење одлука се односи на избор најбољег плана газдовања шумама у односу на постављени проблем одлучивања. Примењени су формирани модели одлучивања за потребе рангирања и избора најбољег плана газдовања шумама у односу на постављене захтеве (производња дрвне биомасе). Приликом избора најбољег алтернативног плана газдовања шумама неопходно је било одредити приоритете између појединих алтернатива или критеријума у ситуацијама одлучивања где учествује један, али и већи број доносилаца одлука и где је присутан већи број критеријума одлучивања у вишеструким временским периодима. Доношењу одлука су претходили конфликтни услови и за решавање оваквих задатака морале су бити примењенe научне методе које су флексибилније од строго математичких метода чисте оптимизације, као што су линеарно програмирање, динамичко програмирање или теорија игара. У овако конфликтној ситуацији неопходно је било направити избор оптималног односа елемената који сачињавају план газдовања шумама (оцена фактора који утичу на дефинисање и рангирање циљева газдовања шумама) са аспекта могућности производње дрвне биомасе. Метода АХП је изабрана због чињенице да циљ овог рада захтева неку врсту оптимизације шуме као сложеног природно еколошко-економског система према коме се константно увећавају захтеви друштва (у овом раду биомаса као нови производ)., As renewable energy sources are gaining ever more importance, the same happens with the possibilities of using woody biomass as an environmentally friendly fuel, but also a resource that can be used in other industries (pulp and paper industry, board and chipboard industry). This study investigates the production potential of woody biomass (wood chips) and its impact on forest management goals in the South Bačka forest area. The thesis examines the mechanisms of preparation and decision-making, which include "enterprise analysis" and "analysis of the environment" with the involvement of stakeholder groups and harmonization of needs and visions with the economic possibilities of woody biomass production. The decision-making refers to the selection of the best forest management plan in relation to the problem of decision-making. The formed models of decision-making were applied for the needs of ranking and selection of the best forest management plan in relation to the imposed requirements (production of woody biomass). When choosing the best alternative forest management plan, it was necessary to determine the priorities between certain alternatives or criteria in decision-making situations involving one, but also a larger number of decision-makers, and where a number of decision-making criteria are present in multiple time periods. Decision-making was preceded by conflicting conditions for solving such tasks. Instruments that were more flexible than strictly mathematical techniques of pure optimization, such as linear programming, dynamic programming, or game theory, had to be applied. In this case, it was necessary to select the optimal ratio of the elements that constitute the forest management plan (assessment of factors that influence the definition and ranking of forest management goals) from the aspect of the possibility of producing woody biomass. This method was chosen because of the fact that the aim of this thesis requires some kind of optimization of the

Carbon materials, prepared by using different methods with ionicliquids, are compared as electrocatalysts for the oxygen reductionreaction (ORR). Materials were synthesized through the hydrothermalcarbonization of glucose and by using the same method in the presence of1-butyl-3-methylimidazolium methanesulfonate {[}bmim]{[}MeSO3] as anadditive. Another two carbon-based materials were prepared by usingionic-liquid-based methods: ionothermal carbonization of glucose using{[}bmim]{[}MeSO3] as a recyclable medium for the carbonization reactionand by direct carbonization of the ionic liquid in a one-step methodusing {[}bmim]{[}MeSO3] as the precursor for N- and S-doped porouscarbon (Carb-IL). Characterization results showed the possibility ofmorphology and porosity control by using {[}bmim]{[}MeSO3]. Allmaterials were subsequently tested for the ORR in alkaline media.Carb-IL showed enhanced and stable electrocatalytic ORR activity, evenin the presence of methanol, ethanol, and borohydride, opening thepossibility for its application in fuel cells.

NiA and NiX zeolites were prepared and characterised using XRD, FTIR and SEM, and subsequently tested as electrodes for hydrogen (HER) and oxygen (OER) evolution reactions in alkaline media. Linear sweep voltammetry and chronoamperometry techniques showed that NiA has higher catalytic activity for these two reactions, as evidenced by higher current densities, which can be correlated with a higher weight fraction of Ni in this electrocatalyst than in the NiX and with its higher conductivity. HER and OER kinetic parameters, including Tafel slope, exchange current density and apparent activation energy were evaluated. Electrochemical impedance spectroscopy analysis yielded values of the resistance of the solution, charge transfer and mass transfer, as well as double layer capacitance and pseudo-capacitance of the working electrode, at different potentials and temperatures. Unlike the HER, during which the mass transfer resistance of the adsorbed intermediate is dominant in the case of NiA, the OER impedance response is controlled by the charge transfer process itself at the potentials of interest for these process. The overall resistance related to the HER is lower for NiA than for NiX. © 2018 Hydrogen Energy Publications LLC

Palladium ion-exchanged zeolite X (PdX) was prepared by zeolite impregnation with palladium acetylacetonate, followed by thermal degradation of the salt. PdX was characterised using SEM-EDS, ICP-OES and XRD. Analysis revealed presence of 7.78 wt.% of Pd in the form of PdO. Subsequently, PdX was tested for hydrogen evolution reaction (HER) in alkaline medium using linear scan voltammetry, chronoamperometry and electrochemical impedance spectroscopy measurements. The influence of addition of carbon black on the materials catalytic performance was also investigated. The HER kinetic parameters, including Tafel slope, exchange current density and activation energy, were determined. In order to provide atomic-level insights, experimental results were complemented by density functional theory calculations. It is suggested that favourable hydrogen adsorption energetics on PdO is responsible for efficient HER catalysis by this novel electrocatalyst. (c) 2017 Elsevier Ltd. All rights reserved.

Heteropoly acid (HPA) was supported on BEA zeolite by optimized synthesis method yielding samples containing different amounts (20 to 50 wt%) of 12-phosphotungstic acid (HPW). The prepared supported HPW samples were subjected to different post-synthesis procedures including calcination and ultrasonication resulting in BEA-HPW (BPW) hybrid materials. These BPW samples were characterized using SEM, N-2-sorption and electrical conductivity measurements. They were subsequently used for the preparation of composites with carbonized polyaniline synthesized in the presence of 5-sulfosalicylic acid, and studied as electrode materials for phenols sensing in acidic, neutral and alkaline media. Linear dependence of current on p-nitrophenol concentration in acidic media was obtained enabling evaluation of limit of detection. Composite electrode gave response to p-nitrophenol presence in alkaline media as well, while no response was recorded in neutral media. The work demonstrates benefits of using novel composite based on BPW hybrid materials and carbonized polyaniline for sensing of phenols in aqueous environmental samples.

Monitoring bromides (Br-) is of crucial importance since bromates, potential human carcinogens, are formed during ozonation of water containing bromides in concentrations GT 100 mu gL(-1). Within this study, silver (Ag) and four carbon-supported Ag catalysts were synthesized by the gamma-radiation method and their morphology and structure examined using transmission electron microscopy, X-ray diffraction, and UV-Vis analysis. The nanocatalysts were tested for Br- sensing in aqueous media using cyclic voltammetry. All five Ag materials exhibited electroactivity for sensing of Br- ions, with pure Ag catalyst giving the best response to Br- ions presence in terms of the lowest limit of detection. Sensing of bromides was also explored in tap water after addition of bromides suggesting that herein prepared catalysts could be used for bromides detection in real samples. Furthermore, sensing of other halogen ions, namely, chlorides and iodides, was examined, and response due to chloride presence was recorded.

Carbon-supported silver nanoparticles (Ag:NPs/C) were synthesized by gamma irradiation-induced reduction method using the poly(vinyl alcohol) or poly(vinyl alcohol)/chitosan polymer as stabilizer. Prepared samples were characterized using transmission electron microscopy and X-ray diffractometry. Subsequently, Ag:NPs/C were studied using rotating disc and rotating ring disc method as electrocatalysts for ORR (oxygen reduction reaction) and BOR (borohydride oxidation reaction) for potential application in alkaline fuel cells. The synthesis method used herein offers simple and fast approach for catalytic ink preparation, since the ink is prepared in one-step radiation process, simultaneously with Ag+ ions reduction. Very high and stable catalytic efficiency toward ORR via 4e(-) path was evidenced during 4000 square pulse polarization cycles. BOR, accompanied with the simultaneous borohydride ion hydrolysis, was found to proceed at the oxidized Ag surface. (C) 2016 Elsevier Ltd. All rights reserved.

У еколошки променљивом шумском пределу, успех у предвиђању одговора шумских екосистема на поремећаје настале природно и индуковане начинима газдовања је неизвестан ако не можемо експлицитно да идентификујемо и објаснимо варијације у еколошким условима, које одређују продуктивност и отпорност екосистема..., In an ecologically variable forest landscape, the success of predicting the response of forest ecosystems to disturbances occurring naturally or induced by modes of management is uncertain if we cannot explicitly identify and explain the variations in environmental conditions that determine the productivity and resilience of ecosystems. This can be efficiently achieved by exploring the ecological classification of habitats. Although created with the primary objective to provide a more complete basis for ecological forest management planning, the typological classification that has been in use in this country can by all its characteristics be considered an ecological classification. The aim of this study was to thoroughly and comprehensively observe all the significant features of the previously defined basic classification units - forest types in the complex of mesophilic beech forests and beech-coniferous forests in the Kopaonik National Park that are significant for modern forest management planning. Among these characteristics are ecotope and biocenosis characterized primarily by the structural shape, mixture ratio, relationships among the tree species and the size, structure, value and safety of wood volume production. In addition, a special goal of this research was to define the objectives of forest management in relation to the existing situation of determined forest types and realistically established priority functions, as well as an orientational functional optimum of these forests. In 27 sample plots of the average size of 0.33 ha, the survey included the following forest coenoecological groups of forest types: forests of spruce, fir and beech (Abieti - Piceenion-Bl. No. 39) on humus-silicate soils, rendzinas, humus, eutric and dystric brown soils, brown and illimerised soils on limestone, the contact of limestone and silicate rocks and brown podzolic soil...