Co, Zn-coordinated ZIF-derived bimetal encapsulated N-doped CNTs for highly effective oxidation of benzyl alcohol at room temperature

Abstract

A ZIF-derived carbon framework offered abundant platforms for the rational design and construction of high-performance nonprecious-metal catalysts. In this study, a Co-coordinated ZIF-derived carbon framework was synthesized by substituting Co for Zn in ZIF-8, followed by pyrolysis. The resultant Co–Zn@C–N, wrapped by carbon nanotubes (CNTs), exhibited superior catalytic performance in the selective oxidation of benzyl alcohol (BnOH), achieving an optimal BnOH conversion of 92% and a benzaldehyde (BzH) selectivity of 92% at room temperature. Characterization results confirmed that the reaction proceeded through a free-radical mechanism, and the CNTs, formed through catalytic graphitization induced by Co nanoparticles, provided solid–liquid reaction interfaces and enhanced the electron transfer between radicals and skeletons. The Co and Zn species, acting as the primary active sites, exhibited a synergistic effect that enabled the good performance of the Co–Zn@N–C catalyst. Moreover, the elevated graphitic degree, substantial content of Co⁰ and graphitic N collectively contributed to the enhanced catalytic performance. Additionally, the catalyst had excellent reusability and stability, manifesting negligible variations in activity across four consecutive experimental cycles. This Co–Zn@N–C catalyst system provides a promising foundation towards the design of highly active non-noble catalysts for organics oxidation reactions under mild conditions.