Cobalt nanoparticles embedded in covalent triazine frameworks (PD-CTF@Co): efficient catalyst for reduction of nitroaromatic compounds

Nitroarenes are chemicals produced by human and industrial activities that contaminate water and soil. These compounds have harmful effects on animals and humans, including cancer, liver damage, and mutagenic effects. Remediation of nitroarenes from the environment is a major concern. In this study, a novel PD-CTF@Co catalytic system was developed and characterized. Covalent triazine frameworks (CTFs) were synthesized via the reaction of 1,4-phenylenediamine with cyanuric chloride, followed by the immobilization of cobalt nanoparticles (Co NPs) onto the CTFs under basic conditions. The resulting PD-CTF@Co system was thoroughly characterized using FT-IR, TGA, XRD, FE-SEM, EDX, and BET analyses to confirm its structure and properties. The catalytic efficacy of PD-CTF@Co was evaluated in the reduction of nitroarenes-specifically 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and 2-chloro-4-nitroaniline (2-Cl-4-NA) using sodium borohydride (NaBH 4 ) as the reducing agent. During the reduction of 4-NP over a period of 120 s, the activity factor (k) and rate constant (kₐₚₚ) of the catalyst were measured as 7.44 s −1  g −1 and 0.0293 s −1 , respectively. For 4-NA and 2-Cl-4-NA, k and kₐₚₚ values were determined to be 3.55 s −1  g −1 , 0.0142 s −1 over 300 s and 3.56 s −1  g −1 , 0.0143 s −1 over 240 s, respectively. Notably, PD-CTF@Co demonstrated remarkable recyclability, maintaining its reduction efficiency between 95% and 97% across five reaction cycles without any significant loss in activity.