Direct Synthesis of Porous Carbon Materials Prepared from Diethyldithiocarbamate Metal Complexes and Their Electrochemical Behavior

Abstract

Porous carbon materials were prepared at low temperatures via thermal decomposition of iron, nickel and cobalt N,N-diethyldithiocarbamates (DDT). X-ray diffraction data showed two peaks at 2θ (25.5° and 43.5°) that indicate the presence of graphite-like structures. Raman spectra displayed D and G bands in the range from 1312 to 1321 cm -1 and 1587 to 1593 cm -1 , respectively, which were fitted with 4 components. All spectra showed two low intensity D* (1190 cm ) bands, assigned to sp 2 -sp 3 bonds in disordered carbonaceous materials and amorphous carbon, respectively. Transmission electron microscopy images showed agglomerates of spherical particles formed by graphitic segments. The results showed that the carbon material obtained from iron N, N-diethyldithiocarbamate, Fe(DDT) 3 , is structurally better organized than the others and the pore size distribution curves confirmed that this material presents high degree of mesoporosity. Voltammetric curves obtained using KOH and H 2 SO 4 electrolytes showed hysteresis behavior typical of capacitors charge/discharge process. The carbon material prepared from Fe(DDT) 3 displayed the highest specific capacitance in acidic media, 59 F g -1 , which was associated to its high degree of mesoporosity. Keywords: carbon materials, diethyldithiocarbamate complexes, electrochemical application IntroductionDifferent physical methods have been used to prepare carbon nanomaterials such as laser ablation, 1,2 arch discharge 3,4 and combustion. 5,6 Thermal decomposition of organic and organometallic precursors [7][8][9] has been presented as a viable alternative to physical methods which use harsh synthesis conditions and yield small amount of products. Different carbon-rich precursors are used to obtain these carbon nanostructures, which can be transformed into graphitic carbon materials of different sizes and shapes. Among these organic precursors, alkynes olygoine derivatives are good candidates due to their high chemical instability, which allows them to undergo different chemical reactions. 10 Various carbon precursors such as benzene, 11 sucrose 12 and phenol resin, 13 are also suitable for the synthesis of carbon materials. Similarly, the pyrolysis of organometallic precursors, such as cobalt acetylacetonate, 14 also yields carbon nanostructures presenting good electrochemical performance which depends on surface area as well as the porosity of these structures. The major problem associated with the method described above is the presence of encapsulated metals.Porous carbon materials are excellent candidates for electrodes in supercapacitors. 15,16 For these materials pore accessibility plays a significant role in the charge storage and the specific capacitance reaches a maximum value when the pore size matches the maximum electrolyte ion dimension. 17 For carbon nanomaterials the surface areas range from 300 to 600 m 2 g -1 and are responsible for electrolyte wetting and rapid ionic motions necessary for da Silva et al. 1905 Vol. 29, No. 9, 2018 a satisfactory electroc...

Sustainable hierarchically porous carbons from bio-oil to remove emerging contaminants

“…95–97 The broad band around 500 cm −1 is assigned to amorphous carbon. 98–100 The Blank_800 material presented a G band more intense than the D band, indicating the presence of a more organized graphitic structure ( I D / I G < 1). On the other hand, the hierarchically porous carbons presented more intense D bands, and therefore higher I D / I G ratios ( I D / I G > 1), indicating a more defective/disorganized graphitic structure.…”