Surface Coordination Decouples Hydrogenation Catalysis on Supported Metal Catalysts

Thiol Treatment Creates Selective Palladium Catalysts for Semihydrogenation of Internal Alkynes

Tuneable bimetallic PdxCu100-x catalysts for selective butadiene hydrogenation

The influence of alumina phases on the performance of Pd/Al2O3 catalyst in selective hydrogenation of benzonitrile to benzylamine

Highly efficient selective hydrogenation of nitrocyclohexane to cyclohexanone oxime in ethylenediamine over MOF-derived catalysts: Effects of Ni-Co alloy and solvent

Activated carbon supported bimetallic Ni-based catalysts were prepared and applied in the selective hydrogenation of nitrocyclohexane (NCH) to cyclohexanone oxime (CHO). The characterization results show that the introduction of the metal promoter can inhibit Ni nanoparticle agglomeration and sintering. Among these bimetallic catalysts, the Cu-Ni/AC catalyst shows the best catalytic performance. The results indicate that introduction of a suitable amount of Cu can effectively promote Ni nanoparticle dispersion, decrease NiO reduction temperature, and facilitate metal Ni exposure. Density functional theory calculation results show that the CuNi (1 1 1) crystal surface possesses higher adsorption energies of H2 and NCH, lower adsorption energies of the active hydrogen (H*) and CHO, and lower reaction energy barriers of NCH hydrogenation to CHO than the Ni (1 1 1) crystal surface. Under the optimized conditions, 1%Cu-20%Ni/AC gives 99.6% NCH conversion and 87.8% high selectivity to CHO. Low-cost bimetallic Cu-Ni catalysts present potential application in economical commercial production of CHO from NCH.

Biodiesel production from hempseed oil using alkaline earth metal oxides supporting copper oxide as bi-functional catalysts for transesterification and selective hydrogenation

Self-Assembly Ultrathin Fe-Terephthalic Acid as Synergistic Catalytic Platforms for Selective Hydrogenation

Bimetallic Pd–Cu catalysts for selective CO2 hydrogenation to methanol

The selective hydrogenation of alkynes to their corresponding alkenes is an important type of organic transformation, which is currently accomplished by modified palladium catalysts. Herein, we rep...

Incorporating Sulfur Atoms into Palladium Catalysts by Reactive Metal–Support Interaction for Selective Hydrogenation

Metallic nickel is known to be an active, but not a selective hydrogenation catalyst for conversion of alkynes to alkenes. On the other hand, nickel oxide is not active. Recently, we have demonstrated that nickel doped into ceria provides an inexpensive catalyst for selective hydrogenation of acetylene in the presence of ethylene. Here, we evaluate various synthesis methods to achieve optimal selective hydrogenation performance. We examined incipient wetness impregnation, coprecipitation, solution combustion, and sol‐gel synthesis to study how the method of preparation affects catalytic structure and behavior. Sol‐gel synthesis, coprecipitation, and solution combustion synthesis methods favor nickel incorporation into the ceria lattice, while incipient wetness impregnation creates segregated nickel species on the ceria surface. For hydrogenation of acetylene, these nickel surface species lead to poor ethylene selectivity due to ethane and oligomer formation. However, when nickel is incorporated into the ceria lattice, ethane formation is prevented even while achieving 100 % conversion of acetylene. Coke formation is also significantly reduced on these catalysts compared to conventional nanoparticle counterparts. We conclude that sol‐gel synthesis provides the optimal method for creating a uniform dopant distribution within the high surface area ceria.

Supported copper nanoparticles are a promising alternative to supported noble metal catalysts, in particular for the selective gas phase hydrogenation of polyunsaturated molecules. In this article, the catalytic performance of copper nanoparticles (3 and 7 nm) supported on either silica gel or graphitic carbon is discussed in the selective hydrogenation of 1,3-butadiene in the presence of a 100-fold excess of propene. We demonstrate that the routinely used temperature ramp-up method is not suitable in this case to reliably measure catalyst activity, and we present an alternative measurement method. The catalysts exhibited selectivity to butenes as high as 99% at nearly complete 1,3-butadiene conversion (95%). Kinetic analysis showed that the high selectivity can be explained by considering H2 activation as the rate-limiting step and the occurrence of a strong adsorption of 1,3-butadiene with respect to mono-olefins on the Cu surface. The 7 nm Cu nanoparticles on SiO2 were found to be a very stable catalyst, with almost full retention of its initial activity over 60 h of time on stream at 140 °C. This remarkable long-term stability and high selectivity toward alkenes indicate that Cu nanoparticles are a promising alternative to replace precious-metal-based catalysts in selective hydrogenation.

Non-thermal RF plasma effects on surface properties of Pd/TiO2 catalysts for selective hydrogenation of acetylene

Thermo-responsive polymer grafted carbon nanotubes as the catalyst support for selective hydrogenation of cinnamaldehyde: Effects of surface chemistry on catalytic performance

Supported palladium nanocatalysts have been reported to be active in selective hydrogenation of acetylene. In this work, non-thermal radio frequency plasma modification has been applied to Pd/Al2O3 catalysts for selective hydrogenation of acetylene in the presence of excess ethylene. High ethylene selectivity, good acetylene conversion activity and high TOF were obtained on the plasma-treated catalysts. To understand the plasma effect, the catalysts were characterized by differential scanning calorimetry in hydrogen (H2-DSC), pulse H2 chemisorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption with ethylene (C2H4-TPD) experiments. XPS and H2-DSC results confirmed that the Pd precursor could be effectively reduced to the metallic state during the room temperature plasma treatment. Plasma treatment also improved the dispersion of Pd particles with strong interaction between Al2O3 support and PdO and Pd nitrate precursors. In addition, C2H4-TPD indicated that plasma treatment could lead to an enhanced catalytic performance on selective hydrogenation of acetylene. It demonstrates that the non-thermal RF plasma treatment is an effective way to manipulate surface properties and the interaction between metals and supports of supported Pd catalysts for selective hydrogenation.