Microwave-Assisted Synthesis of C/SiO₂ Composite with Controllable Silica Nanoparticle Size

A C/SiO₂ composite was produced from 3-aminophenol and tetraethyl orthosilicate (TEOS) by a synthesis protocol that involved microwave irradiation. This protocol featured simultaneous 3-aminophenol polymerization and TEOS hydrolysis and condensation, which were achieved rapidly in a microwave reactor. The SiO₂ component was formed from low-concentration TEOS confined in cetyltrimethylammonium bromide micelles. We demonstrated a control of the SiO₂ particle size, ranging from 20 to 90 nm, by varying the 3-aminophenol concentration. The carbon component provided a microporous structure that greatly contributed to the high specific surface area, 375 m²/g, and served as a host for the nitrogen functional groups with a content of 5.34%, 74% of which were pyridinic type. The composite formation mechanism was clarified from time-series scanning electron microscopy images and dynamic light scattering analysis. An understanding of the composite formation mechanism in this protocol will enable the design of composite morphologies for specific applications

Selective Low-Energy Carbon Dioxide Adsorption Using Monodisperse Nitrogen-Rich Hollow Carbon Submicron Spheres

Monodisperse, nitrogen-doped hollow carbon spheres of submicron size were synthesized using hexamethoxymethylmelamine as both a carbon and nitrogen source in a short (1 h) microwave-assisted synthesis. After carbonization at 550 °C, porous carbon spheres with a remarkably high nitrogen content of 37.1% were obtained, which consisting mainly of highly basic pyridinic moieties. The synthesized hollow spheres exhibited high selectivity for carbon dioxide (CO₂) over nitrogen and oxygen gases, with a capture capacity up to 1.56 mmol CO₂ g^–1. The low adsorption enthalpy of the synthesized hollow carbon spheres permits good adsorbent regeneration. Evaluation of the feasibility of scaling up shows their potential for large-scale applications

Selective Low-Energy Carbon Dioxide Adsorption Using Monodisperse Nitrogen-Rich Hollow Carbon Submicron Spheres

Monodisperse, nitrogen-doped hollow carbon spheres of submicron size were synthesized using hexamethoxymethylmelamine as both a carbon and nitrogen source in a short (1 h) microwave-assisted synthesis. After carbonization at 550 °C, porous carbon spheres with a remarkably high nitrogen content of 37.1% were obtained, which consisting mainly of highly basic pyridinic moieties. The synthesized hollow spheres exhibited high selectivity for carbon dioxide (CO₂) over nitrogen and oxygen gases, with a capture capacity up to 1.56 mmol CO₂ g^–1. The low adsorption enthalpy of the synthesized hollow carbon spheres permits good adsorbent regeneration. Evaluation of the feasibility of scaling up shows their potential for large-scale applications