Fur-imine-functionalized graphene oxide-immobilized copper oxide nanoparticles (Cu(II)-Fur-APTES/GO) are synthesized and found to be a cost-effective, efficient, and reusable heterogeneous nanocatalyst for the preparation of pharmaceutically important xanthene derivatives under greener solvent conditions. Cu(II)-Fur-APTES/GO exhibits excellent result in the synthesis of xanthenes with reduced reaction time (25−50 min) and higher yields (up to 95%) and has a simple procedure, ease of product separation, and no byproducts. Moreover, the nanocatalyst has a Cu loading of 13.5 at. % over functionalized GO which is far superior than the already known metal-based heterogeneous catalysts. The newly synthesized catalyst has been characterized by various physiochemical techniques such as X-ray photoelectron spectroscopy, X-ray diffraction, energy-dispersive X-ray, Raman spectroscopy for structural characterization, field emission scanning electron microscopy and high-resolution transmission electron microscopy for ...

Fur-Imine-Functionalized Graphene Oxide-Immobilized Copper Oxide Nanoparticle Catalyst for the Synthesis of Xanthene Derivatives.

In this study, mesoporous halloysite nanotubes (HNTs) were modified by CuFe2O4 nanoparticles for the first time. The morphology, porosity and chemistry of the CuFe2O4@HNTs nanocomposite were fully characterized by Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM) image, transmission electron microscope (TEM) images, energy-dispersive X-ray (EDX), X-ray diffraction (XRD) pattern, Brunauer-Emmett-Teller (BET) adsorption-desorption isotherm, thermogravimetric (TG) and vibrating sample magnetometer (VSM) curve analyses. The results confirmed that CuFe2O4 with tetragonal structure, uniform distribution, and less agglomeration was located at HNTs. CuFe2O4@HNTs nanocomposite special features were high thermal stability, crystalline structure, and respectable magnetic property. SEM and TEM results showed the nanotube structure and confirmed the stability of basic tube in the synthetic process. Also, inner diameters of tubes were increased in calcination temperature at 500 °C. A good magnetic property of CuFe2O4@HNTs led to use it as a heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives. High efficiency, green media, mild reaction conditions and easily recovery of the nanocatalyst are some advantages of this protocol.

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Mesoporous halloysite nanotubes modified by CuFe 2 O 4 spinel ferrite nanoparticles and study of its application as a novel and efficient heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives.

A facile one-step combustion route is used for the synthesis of a magnetically separable GO–CuFe2O4–ZnO (GCZ) ternary nanocomposite photocatalyst with varying ZnO contents. Transmission electron microscope (TEM) observations show the exfoliation of graphene oxide sheets and decoration with well-dispersed ZnO and CuFe2O4 nanoparticles. The photocatalytic activity of the ternary nanocomposite was tested under solar light irradiation for the photodegradation of several dyes such as rhodamine-B (RhB), methylene blue (MB), methyl orange (MO), and neutral phenol. The evaluation results demonstrate that the ternary GCZ photocatalyst exhibits the best performance compared to GO–CuFe2O4 (GC), GO–ZnO (GZ), CuFe2O4, ZnO, and CuFe2O4–ZnO (CZ) photocatalysts towards the photocatalytic degradation of the dyes. Photoelectrochemical measurements were carried out to provide deep insights into the enhanced photocatalytic activity in the novel ternary nanocomposite. The improved photocatalytic activity of the ternary nanocomposite can be ascribed to the superior light assimilation, proficient charge transfer process, synergistic effects, high surface area, and superior durability of the composite. Furthermore, a possible reaction mechanism has been proposed. Our results have demonstrated that by precisely introducing GO with appropriate metal oxides, a highly efficient photocatalyst can be designed that would assimilate a wider range of visible light. Furthermore, CuFe2O4 nanoparticles themselves have excellent magnetic properties, which are largely maintained in the GCZ composite, and can be simply separated from the suspension system by applying a magnetic field.

A combustion synthesis route for magnetically separable graphene oxide–CuFe2O4–ZnO nanocomposites with enhanced solar light-mediated photocatalytic activity

Photoelectrocatalytic reduction of CO2 into valuable products can provide energy in a sustainable way with leveling off of the concentration of CO2 in our environment. In this study, graphene oxide (GO) incorporated with copper ferrite (CuFe2O4) has been employed to enhance photoelectrocatalytic CO2 reduction under visible light. The TEM and XPS characterization indicated a strong interaction between the CuFe2O4 and GO in the hybrid catalyst. The GO incorporation reduced the e–/h+ recombination in the hybrid catalyst by trapping the photoexcited electrons from CuFe2O4 leading to high methanol yield of 28.8 μmol L–1 cm–2 at 20.5% quantum efficiency. The incident photon current efficiency (IPCE) and Faradaic efficiency for methanol formation were observed as 8.02% and 87%, respectively. The results showed that the photoelectrocatalytic activity for CO2 reduction can be improved by incorporating GO with CuFe2O4, and it provides a universal platform to fabricate GO–CuFe2O4 based hybrid photocatalyst with prom...

Photoelectrocatalytic Reduction of Carbon Dioxide to Methanol Using CuFe2O4 Modified with Graphene Oxide under Visible Light Irradiation

Photoregulated reversible addition–fragmentation chain transfer (RAFT) polymerization

A facile, efficient and environmentally-friendly protocol for the synthesis of xanthenes by graphene oxide based nanocomposite (GO-CuFe2O4) has been developed by one-pot condensation route. The nanocomposite was designed by decorating copper ferrite nanoparticles on graphene oxide (GO) surface via a solution combustion route without the use of template. The as-synthesized GO-CuFe2O4 composite was comprehensively characterized by XRD, FTIR, Raman, SEM, EDX, HRTEM with EDS mapping, XPS, N2 adsorption-desorption and ICP-OES techniques. This nanocomposite was then used in an operationally simple, cost effective, efficient and environmentally benign synthesis of 14H-dibenzo xanthene under solvent free condition. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction, ease of recovery and reusability of the catalyst by a magnetic field. Based upon various controlled reaction results, a possible mechanism for xanthene synthesis over GO-CuFe2O4 catalyst was proposed. The superior catalytic activity of the GO-CuFe2O4 nanocomposite can be attributed to the synergistic interaction between GO and CuFe2O4 nanoparticles, high surface area and presence of small sized CuFe2O4 NPs. This versatile GO-CuFe2O4 nanocomposite synthesized via combustion method holds great promise for applications in wide range of industrially important catalytic reactions.

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Greener Route for Synthesis of aryl and alkyl-14H-dibenzo [a.j] xanthenes using Graphene Oxide-Copper Ferrite Nanocomposite as a Recyclable Heterogeneous Catalyst.

Lakkoji Satish Kumar Achary

Papers

Greener Route for Synthesis of aryl and alkyl-14H-dibenzo [a.j] xanthenes using Graphene Oxide-Copper Ferrite Nanocomposite as a Recyclable Heterogeneous Catalyst.