Homogeneous Ni nanoparticles anchored on mesoporous N-doped carbon as highly efficient catalysts for Cr(VI), tetracycline and dyes reduction

Abstract

The environmental pollution has aroused great concern recently. In this study, a homogeneous dispersed Ni nanoparticles on N-doped mesoporous carbons (Ni@N-MCs) were obtained by pyrolyzing the Ni(II) adsorbed covalent triazine framework (CTF), which have outstanding catalytic reduction ability to Cr(VI), tetracycline and dyes. The as-fabricated Ni@N-MC550 (pyrolyzed at 550 ℃) shows a very rapid reduction rate, which can reduce Cr(VI), methyl blue, methyl orange, Congo red and tetracycline within 2, 1, 5, 7 and 1 min, respectively. This is mainly because the uniform dispersion of Ni nanoparticles in the CTF-derived carbon matrix enhances the catalytic reduction ability of Ni@N-MC550. In addition, the catalyst has good reusability and easy separation of magnetic properties. Further mechanism studies have demonstrated that the reduction of Cr(VI) is due to the active H· generated by the catalytic decomposition of HCOOH by Ni@N-MC550, while the reduction of tetracycline and dyes is due to the transfer of electrons from BH4- to them catalyzed by the synergistic effect of Ni@N-MC550 and NaBH4. This work not only has certain guiding significance for the controllable synthesis of carbon matrix derived from CTFs, but also explores the catalytic reduction of organic and inorganic pollutants by Ni-based catalysts.