Temperature-dependent synthesis of MOF-derived Co@N-doped carbon nanotube nanocomposites toward accelerated reduction of 4-nitrophenol

Designing advanced catalysts with atomic level control over the heterointerfaces and active sites is of great importance for the boosted catalytic reduction reactions. Here, we show that Co nanoparticle-wrapped by Ndoped carbon nanotube heterostructures synthesized by the temperature-dependent pyrolysis of zeolitic imidazolate framework-67 (ZIF-67) precursors have relatively higher catalytic activity toward the reduction of 4-nitrophenol. The well-constructed Co@N-doped carbon nanotube hybrid catalyst calcined at 435 degrees C exhibited catalytic reduction activity superior to those of nanocomposites calcined at other temperatures. The enhanced reduction of 4-nitrophenol performance may be attributed to strong synergistic interactions between welldefined Co nanoparticles and in-situ formed N-doped carbon nanotubes. It is proposed that N-doped carbon nanotubes not only act as the support for Co nanoparticles, but also provide protection for Co nanoparticles from aggregation and oxidation. Furthermore, N-doped carbon nanotubes can enhance the surface adsorption between the components to facilitate electron transfer due to the presence of doped nitrogen atoms. The catalyst also showed high stability with small losses in catalytic activity in recycled experiments, indicating great potential to be cost-effective non-precious metal-based catalysts for scalable and high-performance catalytic reduction reactions.