Heterogeneous Bimetallic Cu–Ni Nanoparticle-Supported Catalysts in the Selective Oxidation of Benzyl Alcohol to Benzaldehyde

Abstract

Three bimetallic Cu–Ni nanoparticle-supported catalysts were synthesized by co-immobilization followed by H2 reduction. A chromium(III) terephthalate metal organic framework (MIL-101), titanium dioxide (TiO2), and carbon (C) with different properties (acidity and Brunauer–Emmett–Teller surface area) were selected as supports for studying the effect of the support nature on the catalytic activity and selectivity in the oxidation of benzyl alcohol. The physicochemical properties of the Cu–Ni-supported catalysts were characterized by XRD, NH3-TPD, nitrogen adsorption/desorption, TEM, EDS, XPS, and ICP-OES. Bimetallic Cu–Ni nanoparticles were highly dispersed on the support. The catalytic activities of CuNi/MIL-101, CuNi/TiO2, and CuNi/C were tested in the selective oxidation of benzyl alcohol to benzaldehyde in the presence of molecular oxygen under mild reaction conditions. The highest benzaldehyde yields were achieved with CuNi/TiO2, CuNi/MIL-101, and CuNi/C catalysts at 100 °C within 4 h under 5, 3, and 3 bar of O2, respectively. The bimetallic Cu–Ni-supported catalysts possessed two types of catalytic active sites: acid sites and bimetallic Cu–Ni nanoparticles. The CuNi/MIL-101 catalyst possessed a high number of acid sites and exhibited high yield during selective benzyl alcohol oxidation to benzaldehyde. Importantly, the catalysts exhibited a high functional group (electron-donating and electron-withdrawing groups) tolerance. Cu–Ni-supported catalysts with an Cu:Ni mole ratio of 1:1 exhibited the highest yield of 47% for the selective oxidation of benzyl alcohol to benzaldehyde. Reusability and leaching experiment results exhibited that CuNi/MIL-101 showed better stability than CuNi/TiO2 and CuNi/C catalysts due to the large porous cavities of MIL-101 support; these cavities can be used to trap bimetallic Cu–Ni nanoparticles and inhibit nanoparticle leaching.

Recent Developments of Advanced Ti3+-Self-Doped TiO2 for Efficient Visible-Light-Driven Photocatalysis

“…There are different advantages depending on the metal combination, and there are even advantages to not using precious metals. It has recently been shown that bimetallic site catalysts can also be applied with TiO 2 [160]. However, this approach requires more research of bimetal sites.…”

Bimetallic Au–Pd alloy nanoparticles supported on MIL-101(Cr) as highly efficient catalysts for selective hydrogenation of 1,3-butadiene

“…69 The MIL-101(Cr)-supported catalysts were synthesized through coimpregnation followed by H 2 reduction. 52,70 First, 24.0 mg of HAuCl 4 $4H 2 O and 7.0 mg of Pd(CH 3 COO) 2 were melted in 1 mL of ethanol. Subsequently, the mixture solution of HAuCl 4 $4H 2 O and Pd(CH 3 COO) 2 was added slowly dropwise into MIL-101(Cr) (0.5 g).…”

“…S7 †). 70 The TEM micrograph and Au-Pd size distribution for the reused Au(2)Pd(1)/MIL-101(Cr) catalyst were presented in Fig. S8.…”

Highlights of the Nanocatalysis in Organic Chemistry

“…In addition, the nature of the nanoparticles support can have a significant influence on their catalytic performance. This aspect is addressed in several papers of this section [1,2].…”

“…The challenging selective oxidation of alcohols to the corresponding carbonyl compounds through sustainable catalytic procedures was addressed by Liu et al [2] focusing on selective oxidation of benzyl alcohol to benzaldehyde, using molecular oxygen as the oxidizing agent. In total, three bimetallic Cu-Ni nanoparticle-supported catalysts were synthesized by co-immobilization followed by H 2 reduction.…”