Mohammad bagher GHolivand

  In the present thesis, thepossibility of using different nanomaterials in fabricating effectiveimmunosensors for rapid diagnosis of prostate cancer has been studied, followedby the construction of the corresponding devices.In Chapter 1, we mainlyfocused on the theoretical information about electrochemical biosensors andimmunosensors based on nanoparticles and nanocomposites.In chapter 2, reports the fabrication of a sensitivelabel-free immunosensor for PSA based on the Au  / polyhedral hollow Co-Cu bimetallicsulfide Nanostructure using differential pulsevoltammetry (DPV) and electrochemical impedancespectroscopy (EIS).Chapter 3, we introduced a novel-typeelectrochemical immunosensor for the quantitative detection ofprostate-specific antigen (PSA) using square wave voltammetry and amperometric measurements.The results on the applicability of gold nanoparticles/ hollowcobalt-based sulfide polyhedral as a modifier and silver nanowires@ZIF-67nanocomposite (Ag NWs@ZIF-67) as a label in the immunosensor are reported. .

  In chapter 1, the growing consumption of conventional fossil fuels and accompanying environmental contamination are affecting global society on an unprecedented scale. Consequently, thereis a quite imminent need to fundamentally adjust the world energy landscape and build clean, low-carbon, safe, and efficient modern energy systems. As an ideal clean chemical fuel with superb gravimetric energy density and energy conversion efficiency, hydrogen energy is expected to be an excellent candidate to replace traditional fossil fuels. Electrochemical water splitting is considered to-be one of the most promising hydrogen production technologies, and it can utilize electricity generated via renewable energy sources, such as solar energy, wind power, geothermal energy, and bioenergy, to form a closed loop of renewable energy. Unfortunately, the large-scale commercial application of electrochemical water splitting is subject to the following three restrictions: (i) a larger overpotential than the theoretical value (1.23 V) needed to drive overall water splitting; (ii) the poor stability of electrode materials; and (iii) high cost caused by the scarcity of noble-metal electrocatalysts. To date, the benchmark electro catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are Pt-group- and Ru/Ir-based noble metal materials with small overpotentials and low Tafel slopes. These noble metals can suffer from dissolution, agglomeration, and poor durability during the water splitting process. The design of electrocatalysts with high electrocatalytic activity is of great importance to reduce the overpotential and improve the efficiency of water decomposition.   

   In recent years, electrochemical methods with the help of modified electrodes have become widely popular as simple, cheap, and accurate methods with high sensitivity in measuring drugs. This thesis presents the development, electrochemical characterization, and analytical application studies of two voltammetric sensors developed for the widely used drug Naproxen (NAP). In this thesis, low-cost electrode modifiers developed from anion-doped transition metal compounds and their composites with carbon nanotubes have been investigated. The thesis is divided into three chapters.

  Electrochemical water-splitting technology for producing “green hydrogen” has attracted increasing attention to the global mission to replace fossil fuel-based energy sources and reduce CO2 emissions. Briefly, an introduction to water electrolysis and a review of effective catalysts are presented in chapter 1. In Chapter 2, we adopted zeolitic imidazolate frameworks-8 (ZIF-8) as the precursor to fabricate ZnS-MOF via facile sulfidation processes. The ZnS-MOF nanostructures were anchored on the surface of the nickel nanowire (denoted as Ni NW@ZnS-MOF nanohybrids) and their catalytic activity for HER, OER, and overall water splitting were studied. The prepared Ni NW@ZnS-MOF revealed a low overpotentials value of 90 and 260 mV at 10 mA cm?2 for HER and OER in 1.0 M KOH solution, respectively. The alkaline electrolyzer assembled by Ni NW@ZnS-MOF provides a low cell voltage of 1.61 V at 10 mA cm?2 current density to boost the overall water splitting and robust stability for 15 h. The superior electrocatalytic activity of Ni NW@ZnS-MOF is due to the facile and effective electron transfer of Ni NW, accessible active sites of ZnS-MOF, and as well as the synergistic effect of the hybrid structures. This finding provides a synthesis strategy to fabricate an efficient free-noble metal catalyst for energy conversion and storage. Achieving the rational design of nanostructures for efficient oxygen evolution reaction (OER) is crucial for green energy utilization. Chapter 3 synthesized the ZnxFe3-xS4 hollow spheres derived from ZnFe-zeolitic imidazolate frameworks (ZnFe-ZIFs) through solvothermal sulfidation with superior OER activity and stability. The ZnxFe3-xS4 electrocatalyst delivers superior OER activity: it requires only low overpotentials of 235 and 285 mV to achieve current densities of 10 and 50 mA cm?2, respectively, as well as a small Tafel slope of 72 mV dec?1. In an alkaline solution, the hollow ZnxFe3-xS4 nanospheres exhibit exceptional durability in the multi-step chronoamperometry test for 20 h. This work offers a blueprint for the design and synthesis of stateof- the-art sulfide-based OER catalysts.

   In the present thesis, the possibility of using different nanomaterials in fabricating effective immunosensors for rapid diagnosis of prostate cancer has been studied, followed by the construction of the corresponding devices. In Chapter 1, we mainly focused on the theoretical information about electrochemical biosensors and immunosensors based on nanoparticles and nanocomposites. In chapter 2, a novel sandwich-type electrochemical immunosensor was introduced for the quantitative detection of prostate-specific antigen (PSA) using amperometric measurements. The results on the applicability of reduced graphene oxide (rGO) and gold nanoparticles (Au  ) as a modifier and gold-silver nanoclusters (Au-Ag NCs) as a label in the immunosensor are reported. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and field-emission scanning electron microscopy (FESEM) was used for the characterization of the modified electrode. The linearity of the immunosensor at the very low concentration range (100.0 fg/ml to 10.0 µg/ml) and a low detection limit (LOD) of 56.01 fg/ml confirmed its high sensitivity for PSA. Chapter 3, reports the fabrication of a sensitive label-free immunosensor for PSA based on the rGO and iron-copper layered double hydroxide (Fe-Cu LDH) using differential pulse voltammetry (DPV). The modification of the pencil graphite electrode (PGE) with the suggested nanocomposite enhanced its response to PSA and achieved a low LOD of 63.24 fg/ml. Further, the proposed structure was studied by computational, morphological, and electrochemical analysis. In conclusion, this thesis wants to serve as a potential orientation for overcoming the shortcomings of the current prostate cancer testing and contribute towards the development of effective immunosensors for PSA biomarker detection and hopefully enhance the diagnosis and prognosis of prostate cancer.

  In this research, measuring the concentration of ammonia and sodium dithionite with a simple and low-cost method has been investigated. For this purpose, a number of experiments have been designed and conducted under standard conditions. Also, a comparison between the accuracy of the mentioned method with the concentration values ??recorded on a number of real samples has been researched. Investigating and measuring the concentration of the substances in question has been done using colorimetric and spectrophotometric methods. The evaluation of the obtained statistical parameters has been calculated using the methods of analysis of variance, RMS and error percentage. The obtained results indicate that salicylate and hypochlorite are effective in changing the color of the solution containing ammonia. Also, the sensitivity of the proposed method in determining the concentration of sodium dithionite in the discussed research was evaluated favorably.

Chapter 1: In this chapter, we briefly review direct methanol fuel cells and the most effective anode catalysts for methanol oxidation. Chapter 2: The lack of low-cost, environmental friendly and efficient electrocatalysts for methanol oxidation in DMFCs has restricted its industrialization; thus, the suggestion of a suitable electrocatalyst can be helpful to solve this problem. Herein microsphere-like the flower of undoped CuS and doped with different percentages of nickel was examined as electrocatalysts for methanol oxidation in alkaline media. The obtained results from different electrochemical measurements including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry showed that the secondary metal doping (in here Nickel), has an egregious effect in electrocatalytic activity improvement. In comparison with undoped CuS and other percentages doped of nickel in CuS (3, 10%), the oxidation current density of methanol was increased on 5% Ni-doped CuS (j~ 140mAcm-2 in 1M methanol); in addition, the electrocatalyst with this percent of nickel (5%) was indicated the lower onset potential than the other electrocatalysts. The good current density and also, the excellent stability (during 6000s) of this electrocatalyst made us to further its investigation toward methanol oxidation reaction (MOR). Chapter 3: A composed structure of MnO2 and (Ni-Cu) sulfide nanospheres as an efficient electrocatalyst for methanol oxidation reaction in alkaline media (0.5M KOH) is suggested here. A simple hydrothermal method was used for the preparation of both (Ni-Cu) sulfide and (Ni-Cu) sulfide/MnO2 electrocatalysts. The final electrocatalyst ((Ni-Cu) sulfide/MnO2) was investigated by different methods, such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopies (EDX), and field emission scanning electron microscopy (FESEM). The electrocatalytic behavior of (Ni-Cu) sulfide nanospheres and (Ni-Cu) sulfide/MnO2 composite toward MOR was examined by different electrochemical measurements including cyclic voltammetry, electrochemical impedance Spectroscopy, and chronoamperometry. The outcome indicated that the (Ni-Cu) sulfide/MnO2 composite relative to (Ni-Cu) sulfide had lower onset potential toward MOR ,and it showed the higher stability (for 6000s). The MnO2 fabrication on bimetal sulfide of (Ni-Cu) is the responsible for enhancement in the electrocatalytic properties of the proposed composite. It seems that the present work has been able to show the performance of MnO2 as a component of a composite in the manufacture of effective catalysts for methanol oxidation.  

امروزه رسيدن به پاسخ در زمان بسيار كم و در محيط مورد نظر از اهميت الاي برخوردار است. سنسورها اين ويژگي را دارند. كه در زمان بسيار كوتاه و در محيط مورد نظر پاسخ لازم را بدهند. علم شيمي نيز مانند ديگر علوم در سيطره سنسورها قرا گرفته است. اين سنسور ها در شيمي انواع مختلفي دارند كه همه آن ها در يك ويژگي مشترك هستن وآن پيگيري تغيرات ويژگي مورد بررسي است. نوعي خاصي از سنسورهاي شيمي كه تغيرات خواص الكتريكي گونه مورد پيگيري   را دنبال ميكند را سنسورهاي الكتروشيميايي مينامند. سنسورهاي الكتروشيميايي داراي ساختاري ساده براي اندازه گيري گونه هاي مختلف مثل يونها،مولكول ها،آلوادگي هاو داروها   مثل ديكلوفناك و...استفاده مي شوند. انچه اهميت دارد طراحي يك سنسورمناسب براي گونه مورد نظر است .اين كار با كمك نانوذرات مختلف براي افزايش سيگنال الكتريكي و همچنين گزينش پذير كردن سيگنال گونه مورد نظر استفاده مي شود. ما در اين ساختارها از نانوذرات كربني براي افزايش سطح و همچنين افزايش سيگنال الكتريكي استفاده كرديم. از كاربرد ديگر نانوذرات اين است كه مي توانند به عنوان يك اتصال دهنده مانند كوانتوم دات ها استفاده شوند. اگر درساختاار سنسورها از يك جز زيستي استفاده شود به آن ها بايوسنسورگفتتهه مي شود و اگر اين جز يك رشته اي DNAباشد ان را اپتاسنسور((aptasensorگويند.براي اندازه گيري كوكايين و سالمونلا دو اپتاسنسور الكتروشيميايي طراحي شد. اين اپتاسنسور داراي حساسيت بالاو گزينش پذيري در تشخيص كوكايين و سالمونلا بودند. در اين كار از الكترود ITO  استفاد شد براي افزايش سطح و همچنين تثبيت كوالانسي رشته اي DNA  سطح الكترود را باكمك روش تبخير گرمايي توسط طلا اصلاح كرديم. در نيتيجه اين كار و با تغيرات غلطت گونه جريان ثبت شده تغغير مي كند با ايجاد منحني كاليبراسيون پي به غلظت گونه در نمونه هاي مورد بررسي شديم. همچنين گزينش پذيري اپتاسنسور را در حضور گونه هاي مشابه بررسي كرديم و نتايج حاصل نشان دهنده كارايي بالا اپتاسنسور هاي طراحي شده بود.  

Abstract Water is one of the challenges of the present century, that can be the source of many developments in the world . Regarding the importantance of these resources and considering this matter that our country is >Keywords: climate zones, water corrosion and scaling potential, orrosion indices, soil corrosion potential, speciation ion   

  In this research, a green and simple preparation method for carbon dots was presented using Crane as a natural source without the need for surface and oxidant passivation agents. The production yield of carbon dots was 13.72% (w / w). The formation of carbon dots with an average size of 9 nm was confirmed by TEM (Transmition Electron Microscopy). Amorphous structure of CDs were confirmed by the X-ray diffraction spectrum (XRD). FTIR spectrometery showed the presence of carbonyl, hydroxyl, carboxylic acid groups and carbon double on the surface on carbon dot. The absorption spectrum of carbon dots with maximum at 215 and 288 nm were recorded.In the second research, a simple and cost effective method for spectrophotometric determination of Fe (?) based on the interaction with Synthesized carbon dots is proposed. The behavior of various factors which affect the reaction i.e. concentration of carbon dots and pH were investigated by central composite design (CCD). Calibration curve in two concentration ranges   at 1×10-6- 9×10-6 M and 1×10-5- 9×10-5 M was linear at the wavelengths of 320 and 325 nm, respectively. This method was used for determination of Fe3+ in tap water, Well and Kimia mineral water. Relative standard deviation (RSD) and relative error (RE) were found to be less than 10% for the determination of Fe (?) in real samples.In the third research, a simple method for determinations the hydrogen peroxide was proposed   the method is based on after addition of hydrogen peroxide to mixture of Fe2+ and CD. In this method, the sample image is examined using the GetData Graph Digitizer software and the intensity of the colors is determined. Two calibration graphs were obtained in the range of 0.1-1.0 ppm and 1.5- 14.0 ppm. This method was used to determine the hydrogen peroxide in the oxidant cream. RSD and RE were lower than 10% obtained for the determination of hydrogen peroxide in the real sample. In the fourth research, a sensing array based on CD was designed to detect heavy metals using chemometric. In this work, the image analysis method was used. In the first part, samples of Fe3+, Fe2+, Pb2+ and Hg2+ were identified with LDA and QDA methods with 75% and 83% accuracy, respectively. In the second part, in addition to the mentioned metals, Cd2+, Ni2+ and Cu2+ in the well water sample with LDA and QDA were identified with 81% and 95% accuracy, respectively

  Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and for the controlled release of DEX at a pH of 1.0 (simulated gastric fluid), at a pH of 6.8 (simulated intestinal fluid) and at a pH of 7.4 (simulated biological fluids) were prepared and characterized. The MMIPs were prepared via precipitation polymerization, using Fe3O4 as a magnetic component, Dextromethorphan (DXM) as a template molecule, methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker in CHCL3 porogen. Magnetic non-molecularly imprinted polymers (MNIPs) were also prepared with the same synthesis procedure as with MMIPs only without the presence of the template. The adsorption kinetics was modelled with the pseudo-first-order and pseudo-second-order kinetics, and the adsorption isotherms were fitted with Langmuir and Freundlich models. The obtained MMIPs were characterized using scanning electron microscopy (SEM), and Fourier transforms infrared (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM) and Thermogravimetric Analysis (TGA). The performance of the MMIPs for the controlled release of Dextromethorphan was assessed, and the results indicated that the magnetic MIPs also had potential applications in the drug controlled release.

In this research, a green and simple carbon dots preparation method was presented using lentil as a natural source without the need for surface and oxidant passivation agents. The production yield of carbon dots is 15.5% (w / w). The formation of carbon dots with an average size of 12 nm was confirmed by TEM (Transmition Electron Microscopy). Amorphous structure of CDs were confirmed by the X-ray diffraction spectrum (XRD). FTIR spectrometery showed the presence of carbonyl, hydroxyl, carboxylic acid groups on the surface on carbon dot, and a carbon double bond on the carbon dot. The absorption spectrum of carbon dots with the maximum absorbance was recorded at 273 nm, and the emission spectrum with a maximum emission at 415 nm and after excitation at of 340 nm were recorded. The fluorescence emission sustainability for these nanoparticles is reported to be about 10 days.In the second research, a simple and cost effective method for spectrophotometric determination of Fe (II) based on the interaction with carbon dots is proposed. The Bear law was obeyed at 315 nm and in concentration range of 2.00?10-6- 2.00?10-3 molar of Fe (II) in the presence of carbon dots. This method was used to determination Fe (II) in tap water samples and mineral water of the Kimia Company. Relative standard deviation (RSD) and relative error (RE) were found to be less than 10% for the determination of Fe (II) in real samples.In the third work, for the determination of Fe (III), in the presence of carbon dots, fluorimetric method was used. The emission of carbon dots at 415 nm was recorded in a concentration range of 2.00?10-7- 2.00?10-5 of Fe (III). This method was used to determin Fe (III) in tap water samples and mineral water of the Kimia Company. RSD and RE were found to be less than 10% for the determination of Fe (III) in real samples.In the fourth work, the interaction between carbon dots and various surfactants was investigated. Using the principal component analysis and the theory of formation of the complex, the critical micelle concentration, the formation constant of surfactant complex and carbon dots, and the formation constant of the complex between micelle and carbon dots for surfactants SDS and CTAB were calculated  

In this thesis we report the fabrication of copper nanoparticles on the multi-walled carbon nano-tubes (MWCNTs) composite film modified glassy carbon electrode ((Cu  /MWCNTs/GCE)) and it was characterized by cyclic voltammetry, a scanning electron microscope and The energy dispersive X-ray (EDX) analysis. Then it was application in the electrochemical Determination of 4-nitrophenol (4-NP) in real samples. Cyclic voltammograms displayed that (Cu  /MWCNTs/GCE) showed high electrochemical catalytic activity contrasted with the MWCNT/ GCE and Cu   / GCE modified. The (Cu  /MWCNTs/GCE) was observed to be appropriate for the selective determination of 4-NP by square wave voltammetry (SWV). Under the optimized condition the fabricated sensor demonstrated two linear concentration ranges from 0.2 to 12.3 and 12.3 to 298.0 ?M with detection limits of 0.06 ?M (S/N = 3). It was proved that this electrode can be utilized for the measurement of (4-NP) in real samples.

  This work is introduces a new electrochemical sensor based on cadmium carbide nanoparticles CdxCy and multi-wall carbon nanotubes MWCNTs modified carbon paste electrode (CPE) for low   level detection of warfarin .The modified electrode was characterized by different methods such as electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The oxidation peak current of warfarin under the optimum experimental conditions was applied for its monitoring for the first time. The calibration curves were linear for warfarin concentrations from 0.009 to 1.4 µM and 1.4 to 500 ?M with a limit of detection of 1.8nM and limit of quantification of 6.6 nM using   differential pulse voltammetric method (DPV). The modified electrode showed excellent stability and was used for determination of warfarin in tablet and human serum with acceptable results.

  1. Sensitive determination of nanomolar concentrations of methadone by differential pulse adsorptive stripping voltammetry in biological and pharmaceuticals samples based on electropolymerization of L-arginine on glassy carbon electrode. And 2. Differential pulse adsorptive stripping voltammetric determination of nanomolar concentrations of trimipramine based on electropolymerization of ?- cyclodextrin and L-arginine on glassy carbon electrode.    

In the first work, we presented a simple, sensitive and selectivity method for Spectrophotometric measuring of hydrogen sulfide in the samples of air by Rhodamine B. This method is as a reagent in an acid environment based on Hydrogen Sulfide reaction with Rhodamine B. Rhodamine B had the maximum emission in wavelength of 548 nm and increasing the Hydrogen Sulfide for doing calibration in concentration range of 0.50- 20.00 mg L-1 by determination range of 0.08 mg L-1 is linear. The optimal conditions of variables, that have effect on reaction, were investigated by using from Central Composite Design (CCD) method. The mentioned method was successfully used for measuring Hydrogen Sulfide in air samples including the environmental air of water and wastewater refinery of Faraman Industrial Town and environmental air of Sulfur Springs of Mahidasht. RSD is calculated less than 5% in real samples in measuring Hydrogen Sulfide and this method is without any interventions. For investigating validity of findings resulted from this method, Methylene Blue Standard Method was used for measuring Hydrogen Sulfide   In the second word, one Paper Bale Sensor was proposed as a method for measuring data resulted from colorimetric in place which is a simple and the most low cost solution for measuring Hydrogen Sulfide in the Air. is a 1.2 cm diameter plane paper disk which has been stained to Rhodamine B and HCl reagents with optimal concentrations obtained by response level method. After introducing standard sample/ solution to sensor, the Hydrogen Sulfide with Rhodamine B reagent responded on sensor and created a dull pinkish combination. image was captured 20 minutes after sample increasing and the Hydrogen Sulfide for doing calibration in concentration range of 0.50- 20.00 mg L-1 by determination rangy of 0.08 mg L-1 was linear. The mentioned method was successfully used for measuring Hydrogen Sulfide in air samples including the environmental air of water and wastewater refinery of Faraman Industrial Town and environmental air of Sulfur Springs of Mahidasht