چكيده به لاتين
Activated carbon is a porous carbon that, due to its low cost, high porosity,and favorable chemical stability, is an important material in various applications such as absorption of heavy metals and volatile organic substances, electrochemical energy storage, especially in supercapacitors, absorption and purification of industrial gases, etc. The synthesis of this material is usually done by two stages of pyrolysis and activation, which in the process of chemical activation, choosing the type of activating agent is considered the main step in controlling the properties and application of activated carbon. The aim of this research is to investigate the factors affecting the synthesis, such as the type of activating agent, pyrolysis and activation temperature, saturation ratio and washing type, on the microstructure, crystallinity and specific surface area of activated carbon obtained from the pyrolysis of Abtonia plant biomass. In this research, the acidic agent, phosphoric acid and the basic agent sodium hydroxide and potassium hydroxide were used in order to check the acidic activating agent, Abtonia leaves were washed, dried and powdered and then combined with phosphoric acid at a ratio of 3:1 and after exposure to It was carbonized overnight at 80 °C, at 800 °C for 90 minutes in a nitrogen atmosphere. In addition, to check the basicity factor, the dried biomass was combined with sodium hydroxide and potassium hydroxide with different ratios of 1:1, 1:2 and 1:3. Then, it was carbonized at 600°C in nitrogen atmosphere for 90 minutes. X-ray diffraction (XRD), Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) were used to investigate the phase, bonding, surface and microstructure of the samples. nitrogen gas adsorption-desorption (N2 adsorption-desorption), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM) were used. According to the results obtained from phase and bonding analysis, amorphous carbon was observed as the main phase in all samples. In addition, the samples activated with basic activators showed a higher specific surface, which is equal to 1052 m2.g-1 and 1237 m2.g-1 for the samples activated with sodium hydroxide and potassium hydroxide with a ratio of 1:2, respectively. In addition, the sample activated with potassium hydroxide with a ratio of 1:2 was used as a supercapacitor electrode for the electrochemical test, which gave the obtained results of a specific capacity to 924 F.g-1 at a current density of 1 A.g-1.
