Exfoliation effect of PEG-type surfactant on Pd supported GO (SE-Pd(nanoparticle)/GO) in cascade synthesis of amides: A comparison with Pd(nanoparticle)/rGO

Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Single-pot tandem oxidative/C-H modification amidation process using ultrasmall PdNP-encapsulated porous organosilica nanotubes

Herein, we studied a single-pot method with a dual catalysis process towards the conversion of primary aromatic alcohols to amides using ultrasmall PdNPs of controlled uniform size (1.8 nm) inside hybrid mesoporous organosilica nanotubes (MO-NTs). The catalyst exhibited excellent performance in water under mild conditions and showed high stability. The catalytic activity towards the tandem oxidation of alcohols in the presence of amine salts and H2O2 to their corresponding amides without producing byproducts was evaluated, and high yields were obtained for all products. The structure of the organosilica nanotubes containing palladium nanoparticles was investigated using various characterization techniques such as XRD, TEM, BET, solid-state 29Si NMR and solid-state 13C CP MAS NMR. Catalyst recycling tests showed that the catalytic power of PdNPs@B-SNTs was preserved after 8 cycles and a slight decrease in catalyst activity was observed.

Diamine-functionalized porous graphene oxide sheets decorated with palladium oxide nanoparticles for the oxidative amidation of aldehydes

C–N coupling between aldehydes and amines by ultra-small PdO NPs adorned diamine functionalized porous GO sheets as retrievable nano-catalyst.

Assessment of GO/ZnO nanocomposite for solar-assisted photocatalytic degradation of industrial dye and textile effluent

An ecofriendly and solar light-responsive graphene oxide wrapped zinc oxide nanohybrid has been synthesized hydrothermally using lemon and honey respectively as chelating and complexing agents. By tuning the reaction conditions, a heterostructure between GO and ZnO has been formed during synthesis. The photocatalytic activity of the synthesized nanohybrid was investigated by degradation of hazardous organic textile dye (methylene blue) as well as wastewater under natural solar light. The nanohybrid exhibited excellent photocatalytic activity towards degradation (~ 89%) of methylene blue (MeB). Furthermore, along with decolorization, 71% of mineralization was also achieved. Interestingly, the nanohybrid has been found to be reusable up to 4 cycles without significant loss of photocatalytic activity. Along with this, the physicochemical parameters of the wastewater generated from textile industry have been also monitored before and after exposure to nanohybrid. The results revealed significant reduction in chemical oxygen demand (COD) (96.33%), biochemical oxygen demand (BOD) (96.23%), and total dissolved solids (TDS) (20.85%), suggesting its potential applicability in textile wastewater treatment.

Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO3)2 or imidazole as catalysts

A new method for the direct synthesis of primary and secondary amides from carboxylic acids is described using Mg(NO3)2·6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source. This methodology is particularly useful for the direct synthesis of primary and methyl amides avoiding the use of ammonia and methylamine gas which can be tedious to manipulate. Furthermore, the transformation does not require the employment of coupling or activating agents which are commonly required.

Boosting Aerobic Oxidation of Alcohols via Synergistic Effect between TEMPO and a Composite Fe3O4/Cu-BDC/GO Nanocatalyst

Fabrication of a nanocomposite catalyst via a novel and efficient strategy remains a challenge; Fe₃O₄ nanoparticles anchored on graphene oxide (GO) sheet-supported metal-organic frameworks (MOFs). In this study, the physicochemical properties of the ensuing Fe₃O₄/Cu-BDC/GO are investigated using Fourier transform infrared spectrum, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray detector, and atomic absorption spectroscopy. The salient features of the nanocomposite such as Cu-MOF, synergistic effect with GO sheets, and magnetic separation characteristics make it an excellent ternary heterostructure for aerobic oxidation of alcohols. The proposed nanocatalyst and co-catalyst 2,2,6,6-tetramethylpiperidine-N-oxyl substantially enhance the catalytic performance for the aerobic oxidation under very mild and sustainable reaction conditions. The heterogeneity of Fe₃O₄/Cu-BDC/GO composite catalyst is affirmed with the added advantage that the initial activity is well maintained even after seven cycles.

K. Raj KR, Ghodekar MM, Patil VS, Gopinath CS, Raja T. Phase Transfer Ceria-Supported Nanocatalyst for Nitrile Hydration Reaction

The present study elaborates the catalytic effect of rare-earth metal oxides (Sm₂O₃ and La₂O₃) over ceria as a support phase transfer catalyst. The synthesized catalysts have been subjected to different characterization techniques, such as field-emission scanning electron microscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, N₂ adsorption-desorption (BET surface analysis), temperature-programmed desorption study (NH₃/CO₂-TPD), Fourier transform infrared, Raman analysis, and X-ray photoelectron spectroscopy to get better insights into the catalytic activity of the catalysts for hydration of nitrile.

Euphorbia leaf extract-assisted sustainable synthesis of Au NPs supported on exfoliated GO for superior activity on water purification: reduction of 4-NP and MB

In the present work, the effect of graphene oxide (GO) architecture and synthesis of gold nanoparticles (Au_NPs) on the surface of GO by using Euphorbia leaf extract was investigated. The as-synthesized catalyst was utilized for reduction of 4-nitrophenol (4-NP) and methylene-blue (MB). The ethanol/water extract of the leaves of Euphorbia was found as a non-toxic, suitable, eco-friendly natural reducing agent in one-step generation of Au nanoparticles onto the GO. The catalyst was characterized by different analysis such as atomic force microscopy, powder X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, SEM-mapping, transmission electron microscopy, and atomic absorption spectrometry. The high catalytic performance of the surfactant exfoliated gold-GO (SE-Au_NPs/GO) towards the reduction of 4-NP to 4-aminophenol (4-AP) and reduction of MB to leucomethylene blue (LMB) under mild conditions, in water and at room temperature, was exhibited. Graphical abstract.