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In this work, a convenient approach has been applied to discover the potential valorization of biomass waste such as orange peel in which PdCu-based nanostructured systems were synthesized via a one-step in-situ dry-milling approach to obtain the benign bimetallic catalysts with different palladium(Pd) and Copper(Cu) loadings on the orange peel support (Pd1%Cu1%, Pd0.3%Cu0.7%, Pd0.5%Cu0.5%, Pd0.5%Cu1%). Catalytic applications of these new composites were investigated in the Sonogashira-Hagihara coupling reaction as well as the Sonogashira–click reaction sequence to the preparation of substituted 4-aryl-1,2,3-triazoles and reduction of nitroaromatics under mild reaction conditions. Catalytic tests with the four activated carbons catalysts showed that the C@Pd1%Cu1% catalyst was the most active in the Sonogashira-Hagihara coupling reaction compared to the other catalysts. Also, the C@Pd0.5%Cu0.5% catalyst showed the highest catalytic activity in the reduction of 1-chloro-4-nitrobenzene and 4-nitrophenol in comparison with other prepared carbon catalysts.

Gold catalysts have been reported to be applied only for the Sonogashira-Hagihara reaction of iodobenzene and phenylacetylene under harsh reaction conditions, while the scope of the reaction has not been expanded for coupling reaction of other aryl halides and alkynes. In this investigation, a cost-effective, Pd-free catalyst based on mesoporous magnesium oxide supported bimetallic AuNi nanoparticles (m-MgO@AuNi) have been synthesized by hydrothermal method and its efficiency has been demonstrated in Sonogashira-Hagihara cross-coupling reaction. The m-MgO@AuNi nanocatalyst was structurally and morphologically characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and the mesoporous structure of MgO has been confirmed through BET analysis. Using this palladium-free catalyst, Sonogashira-Hagihara coupling reaction of aryl iodides and aryl bromides with alkynes have been successfully performed and catalyst was recycled for several times. The results demonstrate that the synergistic effect between Au, Ni and mesoporous MgO support plays key role in enhancement of m-MgO@AuNi catalytic activity in Sonogashira-Hagihara reaction.

Bimetallic Fe–Cu MOF was effectively synthesized through a one-pot solvothermal process and successfully characterized by TEM, XPS, SEM, XRD, BET, EDX, elemental mapping, and FT-IR analysis. This bimetallic MOF was employed as a catalyst in the reduction of nitroarenes at room temperature and as well as in the reduction of dyes, for example, methyl orange (MO) and methylene blue (MB). Results pointed to Fe–Cu MOF exhibiting outstanding catalytic performance for both room temperature reactions. The catalytic activity of Fe–Cu MOF in comparison with Fe-MOF and Cu-MOF in the nitroarenes reduction indicated a superior activity compared with single-metal MOFs. Activity of Fe–Cu MOF catalyst did not change after its recycling and reusing for seven consecutive cycles in nitrobenzene reduction.

FeCu MOF has been prepared via solvothermal method and the resulting bimetallic MOF was employed for stabilization of Pd species. Obtained Pd(II)@NH2BDC-FeCu MOF could act as an effective environmental catalyst in Sonogashira-Hagihara coupling reaction and the reduction of organic dyes. This recyclable catalyst demonstrated high catalytic activity for Sonogashira reaction of aryl iodides and aryl bromides with alkynes. Rhodamine B and methyl red as organic dyes were instantly reduced. Pd(II)@NH2BDC-FeCu/MOF was characterized by TEM, XPS, FT-IR, BET, XRD, and SEM. In addition, the synthesized catalyst was recyclable and reusable for 6 sequential times without deteriorating remarkable in catalytic performance for reaction of iodobenzene with phenylacetylene.

A Palladium supported onto an ionic liquid-modified carbon nanotube is prepared. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) are used to complete its characterization. The application as catalyst in the copper-free Sonogashira-Hagihara coupling is also studied employing different substrates. This heterogeneous catalyst is successfully recycled for 5 consecutive identical reactions maintaining its efficiency. After this fifth catalytic run the catalyst is characterized again.