Microporous carbon spheres derived from resorcinol-formaldehyde solutions. A new approach to coat supports

Abstract

Microporous carbon spheres of different morphology and porosity were synthesized from resorcinol-formaldehyde solutions by a simple and fast procedure. Polymeric spheres were shaped by means of microwave heating. Carbonization and activation with carbon dioxide were then applied to obtain the intended final carbon spheres. The influence of the pH, heating time and thermal treatments on the morphology and porosity of the carbon spheres was investigated. It was found that the size of the spheres, can be easily controlled during the synthesis process, specifically by modifying the pH of the precursor solution. An increase in the pH value from 3 to 5 led to carbon spheres with sizes of 4 µm and 3.5 µm, respectively, whereas time seemed to have no effect. These results have been attributed to the chemical mechanisms of the polymerization reaction. On the other hand, microporosity was tailored during the thermal treatments. Carbon spheres with surface areas of 630 m 2 /g and 1500 m 2 /g were obtained by applying carbonization and physical activation, respectively. Furthermore, the synthesis method proposed allows to obtained liquid polymerized inks that can be further used to coat ceramic supports by a simple spray-drying process, which enhances the potential of these materials for several applications.

ZnO/Carbon Spheres with Excellent Regenerability for Post-Combustion CO2 Capture

“…Furthermore, the merging of carbon spheres was noticed. According to [ 36 ], the presence of oxygen groups on the surface of carbon with CO 2 at high temperatures may favor the phenomenon of joining single spheres together.…”

Pressureless and Low-Pressure Synthesis of Microporous Carbon Spheres Applied to CO2 Adsorption

“…For the samples with addition of potassium oxalate, a larger degree of merging between spheres was also observed ( Figure 1 e,g). Rey-Raap et al [ 17 ] also observed that the activation process of carbon spheres leads to a larger degree of merging between spheres and claimed that it can be associated with the presence of oxygenate functional groups and their strong interactions with CO 2 at high temperatures.…”

“…In the latter approach, reactants are placed in various types of metal autoclaves and usually heated to a (rather low) desired temperature. Recently, microwave reactors have attracted more attention as a new efficient heating method [ 17 , 18 ]. Several parameters, e.g., carbon source, temperature, pH, or reaction time, can influence the morphology and properties of carbon spheres.…”

Adsorption of CO2 on Activated Carbon, Fe‐Based Metal Organic Framework, ZnO, and CaO for Carbon Capture and Storage Application

“…Furthermore, the merging of spherical particles was noticed. According to Rey-Raap et al [20], the presence of oxygen groups on the surface of carbon with iron at high temperatures may favor the phenomenon of joining single spheres together [21].…”