The influence of thermal treatment on the electrochemical properties of carbon–Ni–Pd composites

Abstract

Resorcinol-formaldehyde (RF) hydrogel and RF-nickel-palladium (RF-Ni-Pd) hydrogel were synthesized by sol-gel polycondensation followed by ambient drying. Carbon gel and carbon-nickel-palladium doped gels were prepared by carbonizing the RF and RF-Ni-Pd gels at 900°C under a nitrogen atmosphere. The goal of this study was to determine the effect of oxidative thermal treatment on the electrochemical activity of nickel-palladium doped carbon gels (C-Ni-Pd). The scanning electron microscopy analysis, adsorption and X-ray diffraction measurements showed that the admixture of Ni and Pd to carbon matrix resulted in the modification of morphological, porous and crystalline features. It has been demonstrated that composite C-Ni-Pd composed of sphere-like granules incrusted with well-crystalline nickel and palladium particles exhibits electrochemical activity in 6 M KOH aqueous solution. Thermal treatment of the composite carried out in air at 450°C brought about the improvement of electrochemical activity in the potential range of the hydrogen sorption/desorption reaction.

Preparation and electrochemical performance of nitrogen-enriched activated carbon derived from silkworm pupae waste

“…The broad peaks at approximately 24.7 and 44.6 of the YP50 are caused by amorphous carbon, while the sharp peak at approximately 26.4 of the P-ACs corresponding to the (002) plane of the graphitic carbon. 24 The difference in crystalline structure of YP50, a typical steam-activated carbon from coconut shell, and the P-ACs is likely due to the difference in the activation process between steam activation and chemical activation, and the specic characteristics differences between the coconut shell and silkworm pupae raw materials.…”

The effect of catalyst and heat treatment on the properties of carbon–metal composites

“…Resorcinol-formaldehyde (RF) hydrogels were synthesized by the polycondensation of resorcinol (R) with formaldehyde (F), and sodium carbonate (C) as a base catalyst following a method already applied elsewhere [21]. Molar ratios R/F and R/C were 0.5 and 1000, respectively.…”

“…A Hg/HgO/6 M KOH system (-0.098 V vs. normal hydrogen electrode) and a platinum spiral were used as the reference and counter electrode, respectively. The CV measurements were carried out in the potential range from -1.2 to 0.0 V with the scan rate 1 mV/s, according to the conditions described in detail in the earlier work [21].…”

“…One area of significant interest is incorporation of metal species into the carbon framework with the goal of modifying the structure, conductivity, and catalytic and electrochemical activity of the carbon gels. Various metal-doped carbon gels have already been prepared and characterized from the point of view of physicochemical properties [17][18][19][20][21]. Metal-doped carbon materials are attractive for several applications, for example in electrochemistry [9,14,[22][23][24] or catalysis [25][26][27][28], but the pores of carbon gels obtained by drying in ambient conditions are often closed, the chemical and electrochemical activity can not be fully utilized.…”

Removal of lead(II), copper(II), cobalt(II) and nickel(II) ions from aqueous solutions using carbon gels

“…There are three main methods of drying organic gels: drying with supercritical CO 2 [5,6] creating gels named aerogels, drying at ambient temperature [7][8][9][10],which gives xerogels or by freeze drying [11]cyrogels. During carbonisation, organic gels are heated from room temperature to the required pyrolysis temperature, generally 600-1050°C [12][13][14][15].…”