A comparison between two Pd‐Ni catalysts supported on two different supports toward Suzuki‐Miyaura coupling reaction

Abstract

When a single metal fails to promote an efficient Suzuki-Miyaura coupling reaction at ambient temperature, the synergistic cooperation of two distinct metals might improve the reaction. To examine the synergistic effect of palladium and nickel for catalyzing Suzuki coupling reaction, g-C 3 N 4 supported metal nanoparticles of PdO, NiO and Pd-PdO-NiO were prepared, characterized and their catalytic activities evaluated over different aryl halides at room temperature and 78°C.The morphological characterization of Pd-PdO-NiO/g-C 3 N 4 demonstrated that the bimetallic particles were uniformly dispersed over the g-C 3 N 4 layers with diameters ranging from 3.5-7.7 nm. XPS analysis showed that nanoparticles of Pd-PdO-NiO consisted of Pd(II), Pd(0) and Ni(II) sites. The experiments performed on the catalytic activity of Pd-PdO-NiO/g-C 3 N 4 showed that the prepared catalyst demonstrated an efficient activity without using toxic solvents.

Bimetallic PdxNi1‐x and PdxCo1‐x nanoparticles supported on K‐OMS‐2: Highly active, environmentally friendly and reusable nanocatalysts for the Suzuki–Miyaura cross‐coupling reactions in water

“…The oxidation states of Pd, Ni or Pd, Co were intensely explored by HR‐XPS analysis of Pd 0.2 Ni 0.8 @K‐OMS‐2 and Pd 0.2 Co 0.8 @K‐OMS‐2. Figure 6b,c display HR‐XPS spectra obtained at Ni 2p and Pd 3d core‐level and their deconvoluted chemical states for Pd 0.2 Ni 0.8 @K‐OMS‐2, which shows that the existence of nickel (II) oxide NiO (853.6 eV for 2p3/2, 872.6 eV for 2p1/2) [ 34 ] and metallic Pd (334.6 eV for 3d5/2; 339.8 eV for 3d3/2) together with small amount of palladium (II) oxide (PdO) (336.9 eV for 3d5/2; 342 eV for 3d3/2). [ 35 ] The high‐resolution Pd 3d and Co 2p XPS spectra of Pd 0.2 Co 0.8 @K‐OMS‐2 along with their deconvoluted chemical states are shown in Figures 7b,c, revealing that the chemical states of Pd and Co in Pd 0.2 Co 0.8 @K‐OMS‐2 are Pd(0) (334.6 eV for 3d5/2; 339.8 eV for 3d3/2), Pd (II) (336.9 eV for 3d5/2; 342 eV for 3d3/2), and Co (II) (781.25 eV for 2p3/2, 798.84 eV for 2p1/2).…”

“…[33] The surface elemental composition and the oxidation state of Pd 0. [34] and metallic Pd (334.6 eV for 3d5/2; 339.8 eV for 3d3/2) together with small amount of palladium (II) oxide (PdO) (336.9 eV for 3d5/2; 342 eV for 3d3/2). [35] The high-resolution Pd 3d and Co 2p XPS spectra of Pd 0.2 Co 0.8 @K-OMS-2 along with their deconvoluted chemical states are shown in Figures 7b,c, revealing that the chemical states of Pd and Co in Pd 0.2 Co 0.8 @K-OMS-2 are Pd(0) (334.6 eV for 3d5/2; 339.8 eV for 3d3/2), Pd (II) (336.9 eV for 3d5/2; 342 eV for 3d3/2), and Co (II) (781.25 eV for 2p3/2, 798.84 eV for 2p1/2).…”