Abstract:
In this study, the preparation of economical Cu-based catalysts for Pd-free coupling and oxidation reactions was demonstrated. For the preparation of the Cu-based catalyst, first, a Cu-BTC MOF was prepared
under ambient conditions. The Cu-BTC MOF was then carbonized in N2 to obtain Cu–Cu2O-supported
carbon materials. Moreover, the Cu–Cu2O-supported carbon material was subjected to heating in O2 to
obtain the CuO–Cu2O-supported carbon material. Formation of Cu-BTC-MOF, Cu–Cu2O, and CuO–
Cu2O was confirmed via powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The
amount and types of carbon present in the catalyst were confirmed using thermogravimetric analysis and
Raman spectroscopy, respectively. The textural properties of the materials were determined using N2-
sorption measurement. The morphology, porosity, and elemental composition were confirmed via the
scanning and transmission electron microscopy images. The Cu–Cu2O-supported carbon material successfully catalyzed the Sonogashira cross-coupling (C–C cross-coupling reaction), Ullmann amination
(C–N coupling reaction), and A3 coupling (decarboxylative C–C and C–N coupling) reactions; moreover,
the CuO–Cu2O-supported carbon material successfully oxidized diphenylmethane in O2 at 1 atm. The
catalysts were found to be stable and recyclable. Heterogeneity of the reaction was confirmed via the CS2
poisoning and hot-filtration tests. The presence of the optimum amount and the suitable oxidation state
of Cu in the stable nanoporous carbon matrix having graphitic conducting nature were responsible for
the excellent activity and recyclability. The results demonstrate that the applications of these Cu-based
catalysts can be extended to several catalytic reactions that are known to be catalyzed using Pd and other
costly metals.
