Nanodiamond–silicon nitride composites for CO₂ capture technology

Innovative nanodiamond (ND)–silicon nitride polymer‐derived ceramics with different concentrations of nanocarbon phase were developed within the present work and their performance as adsorbent materials for CO 2 was established. The novel preparative approach consists in the synthesis of a polysilsesquiazane in the presence of different concentrations of chemically functionalized NDs, yielding homogeneous ND–polysilsesquiazane composites which were subsequently thermally converted in Argon atmosphere into micro‐ and mesoporous ND–Si 3 N 4 nanocomposites. The ND–Si 3 N 4 nanocomposites were carefully investigated by several characterization methods such as vibrational spectroscopy, solid‐state magical angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, X‐ray diffraction, brunauer‐emmett‐teller (BET), high‐resolution transmission electron microscopy (HRTEM), and CO 2 adsorption, respectively. The incorporation of NDs in silicon nitride matrix enhances the resistance against crystallization of silicon nitride phase, as α‐Si 3 N 4 , at T > 1300°C, while their full graphitization is also shifted to higher temperatures as compared to their raw analogues, demonstrating the synergistic effect of composing phases. The results achieved within the present study allow for designing advanced and well‐defined micro‐ and mesoporous 0D ND‐containing silicon nitride composites with tailored structural features suitable for CO 2 capture technology.