Carbon-based Materials

Carbon-based Materials

Graphene
Selmiye Alkan Gürsel
Veera Sadhu
  • Functionalized Graphenes
    Functionalization of Graphene

    Graphene based nanomaterials are highly important because of their unique properties such as high contact surface area, high electrical conductivity and their enormous stability. Graphene and related materials have been used as promising catalyst supports in energy conversion and storage applications. In our research, in order to produce more efficient catalyst supports, we successfully modified graphene with various active functional groups such as amine, thiophene, fluorosilane, and RGD peptide by mono and multi-functionalization of graphene oxide. Further, modified polyol process was used to obtain specifically guided growth of Platinum (Pt) nanoparticles on these modified graphene surfaces. Consequently, better dispersion of Pt nanoparticles were obtained with delicate control-ability. As a result, the electrocatalytic activity (ECSA and ORR) was greatly enhanced. These promising nanomaterials can serve as potential candidates for high performance polymer electrolyte membrane fuel cells.

Selmiye Alkan Gürsel
Fevzi Çakmak Cebeci
Melih Papila
  • Graphene/polymer Nanocomposites

    In this work, superior electrical, mechanical and antibacterial properties of graphene nanosheets were readily incorporated in electrospun poly (vinyl alcohol) (PVA) fibers. The major advantage of this approach is that via co-solvent addition method, a well-dispersed hydrophobic graphene nanosheet distribution in hydrophilic PVA solution was achieved. Thus, improving the final fibers' mechanical and electrical properties. As the final stage of this investigation, effectiveness of this method in preparation of ternary PVA/PANI/rGO fibers and their antibacterial performance was studied. It was shown that effective distribution of conducting components in biodegradable PVA fibers resulted in high antibacterial activity of the final electrospun mats.


Metal Organic Frameworks
Selmiye Alkan Gürsel
Emre Biçer
  • Metal organic frameworks

    Metal-organic frameworks (MOFs) are a new class of porous, highly crystalline materials consisting of metal nodes connected by organic linkers. Due to the simplicity of manipulating or substituting the metal centers and ligands, there are limitless number of possible combinations, which is attractive from a design standpoint. MOFs exhibit many unique properties due to their tunable pore sizes, thermal stability, high volume capacities, large surface areas, and desirable electrochemical characteristics. Our aim is to prepare well dispersed and ordered metal nanoparticles (Ni, Co or Mn) on graphene. For that purpose we have been synthesizing graphene supported MOFs first and then by annealing (to remove organic parts) we will achieve desired catalyst layer. It is also possible to obtain bimetallic nanoparticles starting from two diffent MOFs.


Biomass
Yuda Yürüm

M. Baysal, K. Bilge, B. Yılmaz, M. Papila, Y. YÜRÜM
Preparation of high surface area activated carbon from waste-biomass of Sunflower piths:
Kinetics and equilibrium studies on the methylene blue adsorption,
Journal of Environmental Chemical Engineering, 6, 1702-1713, 2018.

Sunflower pith (SP), a vast agricultural waste is herein used as a precursor material for highly porous low density activated carbon production. Porosity and flake-like microstructure of the SP in its natural form are shown by micro-computed tomography (Micro-CT). Carbonization process turns the SP into thin, separated carbon flakes of 200 nm thickness. Two types of alkaline based chemical activation with KOH and NaOH are performed to yield SP based activated carbon (AC), K-SPAC and N-SPAC, respectively. Microstructural changes upon carbonization and activation process are elaborated by RAMAN, FTIR and SEM analyses. BET Surface area of the NaOH-activated N-SPAC was calculated as 2690m2/g and was higher than KOH-activated K-SPAC with 2090m2/g. Maximum adsorption capacity of N-SPAC was calculated as 965 mg/g whereas it was 580 mg/g for K-SPAC. Adsorption kinetic studies for N-SPAC revealed that at a low initial concentration of dye (500 mg/L), the pseudo first-order kinetic model was predictive. On the other hand, at high initial MB concentration (1000 mg/ L), the results indicate that the adsorption kinetics follow the Elovich model with intraparticle diffusion as one of the rate-determining steps. In conclusion, overall results suggest that thanks to its highly porous microstructure, the SP is an alternative renewable AC precursor choice for dye removal applications.