Biomass-Derived Activated Carbon-Supported Copper Catalyst: An Efficient Heterogeneous Magnetic Catalyst for Base-Free Chan–Lam Coupling and Oxidations

Abstract

Development of heterogeneous catalysts from biomass-derived activated carbon is a challenging task. Biomass-derived activated carbon possesses a large specific surface area, highly porous structure, and good thermal/chemical stability. Magnetic copper catalysts based on biomass-derived activated carbon exhibited good catalytic activity in base-free Chan–Lam coupling and oxidations. Herein, biomass-derived activated carbon was prepared by the carbonization of neem dead leaves (abundant waste biomass) followed by chemical activation with KOH. Such a porous carbon material was used as a low cost and highly efficient support material for the preparation of inexpensive and environmentally benign magnetic catalysts [Cu@KF-C/MFe2O4, M = Co, Cu, Ni, and Zn]. In addition, KF modification was done to impart basic character to the catalyst that can perform C–N coupling under base-free conditions. Initially, Brunauer–Emmett–Teller (BET) analysis of the synthesized catalysts was carried out, which indicated that Cu@KF-C/CoFe2O4 possess more surface area as well as pore volume, and so accounting for the highest activity among the other synthesized catalysts. Further, X-ray photoelectron spectroscopy (XPS) analysis was performed, which inferred that Cu@KF-C/CoFe2O4 contains most of the copper in reduced form, i.e., Cu(0), which is the active species responsible for better catalytic activity toward Chan–Lam coupling reactions as well as oxidation of alcohols and hydrocarbons. The physiochemical properties of the most active catalyst, Cu@KF-C/CoFe2O4, was examined by BET, XPS, Fourier transform infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission gun scanning electron microscopy (FEG-SEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX) mapping, energy dispersive X-ray (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), powder X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Moreover, Cu@KF-C/CoFe2O4 shows excellent stability as well as reusability and could be easily separated with the help of an external magnet.

CoFe2O4 Nanoparticle Decorated Hierarchical Biomass Derived Porous Carbon Based Nanocomposites for High-Performance All-Solid-State Flexible Asymmetric Supercapacitor Devices

“…The deconvoluted C 1s spectra show three peaks at 284.8, 286.2, and 288.7 eV due to the presence of C–C, C–O, and CO, respectively (Figure a). , The high-resolution XPS spectrum of Co 2p (Figure b) is deconvoluted, the peaks at 780.4 and 796.1 eV correspond to the spin–orbit splitting of Co 2p 3/2 and Co 2p 1/2 , respectively, and their respective shakeup satellite (sat) peaks at 784.7 and 802.8 eV are found. This is evidence of the presence of Co in its Co 2+ oxidation state in the CF-PC nanocomposite. , The high-resolution Fe 2p spectrum is fitted with four main peaks (710.8, 713.6, 723.9, 726.4 eV) and two satellite peaks (719.1, 732.62 eV), which is depicted in Figure c. The peaks at 710.8 and 723.9 eV are assigned to Fe 2p 3/2 and Fe 2p 1/2 of Fe 3+ in the octahedral sites whereas the peaks at 713.6 and 726.4 eV are assigned to Fe 2p 3/2 and Fe 2p 1/2 of Fe 3+ in the tetrahedral sites. , Figure d depicts the high-resolution O 1s spectrum, fitted with two peaks at 529.9 and 531.8 eV corresponding to the M–O (M = Co 2+ , Fe 3+ ) bond in the lattice sites and oxygen containing functional groups, respectively. , …”

“…This is evidence of the presence of Co in its Co 2+ oxidation state in the CF-PC nanocomposite. 13,33 The high-resolution Fe 2p spectrum is fitted with four main peaks (710.8, 713.6, 723.9, 726.4 eV) and two satellite peaks (719.1, 732.62 eV), which is depicted in Figure 3c. The peaks at 710.8 and 723.9 eV are assigned to Fe 2p 3/2 and Fe 2p 1/2 of Fe 3+ in the octahedral sites whereas the peaks at 713.6 and 726.4 eV are assigned to Fe 2p 3/2 and Fe 2p 1/2 of Fe 3+ in the tetrahedral sites.…”

CoFe2O4 Hollow Spheres-Decorated Three-Dimensional rGO Sponge for Highly Efficient Electrochemical Charge Storage Devices

“…The high-resolution Co 2p spectrum (Figure 4a) is fitted with two main peaks corresponding to the spin−orbit splitting of Co 2p 1/2 (796.8 eV) and Co 2p 3/2 (781.2 eV) and their two shake-up satellite peaks (803.4 and 785.9 eV), which confirms the presence of Co(II). 27,39 In the deconvoluted Fe 2p spectrum, four main peaks (711.04, 713.5, 724.3, 727.1 eV) and two shake-up satellite peaks (719.5, 733.2 eV) were observed (Figure 4b). The peaks at 724.3 and 711.04 eV are due to the spin−orbit splitting of Fe 2p 1/2 and Fe 2p 3/2 orbitals of Fe(III) present in the octahedral sites, and the peaks at 727.1 and 713.5 eV are from the Fe 2p 1/2 and Fe 2p 3/2 orbitals of Fe(III) in the tetrahedral sites.…”

NiFe2O4@B,N,F-tridoped CeO2 (NFTDNC): a mesoporous nanocatalyst in the synthesis of pyrazolopyranopyrimidine and 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives and as an adsorbent

“…Spinel ferrites, a class of bimetallic magnetic nanomaterials exhibit an extensive variety of applications in gas sensing, drug delivery, high density, ferrofluids, microwave devices, electro-communication and various other fields. [28][29][30] Nickel ferrite, a unique magnetic spinel material has small hysteresis, tunable bandgap (∼1.7 eV) resulting in efficient solar light utilization, chemical durability and high magnetic separation. 31,32 The domino multicomponent reaction (MCR) inevitably engrossed the organic chemists as it not only encompasses the merits of multicomponent reactions but also addresses their demerits such as more wastage and lower yield.…”

“…Spinel ferrites, a class of bimetallic magnetic nanomaterials exhibit an extensive variety of applications in gas sensing, drug delivery, high density, ferrofluids, microwave devices, electro-communication and various other fields. 28–30 Nickel ferrite, a unique magnetic spinel material has small hysteresis, tunable bandgap (∼1.7 eV) resulting in efficient solar light utilization, chemical durability and high magnetic separation. 31,32…”