Recent Progress in Pd-Based Nanocatalysts for Selective Hydrogenation

Abstract

Selective hydrogenation plays an important role in the chemical industry and has a wide range of applications, including the production of fine chemicals and petrochemicals, pharmaceutical synthesis, healthcare product development, and the synthesis of agrochemicals. Pd-based catalysts have been widely applied for selective hydrogenation due to their unique electronic structure and ability to adsorb and activate hydrogen and unsaturated substrates. However, the exclusive and comprehensive summarization of the size, composition, and surface and interface effect of metal Pd on the performance for selective hydrogenation is still lacking. In this perspective, the research progress on selective hydrogenation using Pd-based catalysts is summarized. The strategies for improving the catalytic hydrogenation performance over Pd-based catalysts are investigated. Specifically, the effects of the size, composition, and surface and interfacial structure of Pd-based catalysts, which could influence the dissociation mode of hydrogen, the adsorption, and the reaction mode of the catalytic substrate, on the performance have been systemically reviewed. Then, the progress on Pd-based catalysts for selective hydrogenation of unsaturated alkynes, aldehydes, ketones, and nitroaromatic hydrocarbons is revealed based on the fundamental principles of selective hydrogenation. Finally, perspectives on the further development of strategies for chemical selective hydrogenation are provided. It is hoped that this perspective would provide an instructive guideline for constructing efficient heterogeneous Pd-based catalysts for various selective hydrogenation reactions.

Hybrid Pd-Nanoparticles within Polymeric Network in Selective Hydrogenation of Alkynols: Influence of Support Porosity

“…At present, palladium-catalyzed reactions can be considered as the most abundant in fine chemistry, which makes palladium catalysts extremely important [1][2][3][4][5][6][7]. Recently, there has been increased interest in environmentally benign Pd-catalyzed processes that are also economically viable.…”

“…max (S) ± 0.5, % 1 R 0 ± 0.1, mol sub /(mol Pd *s)3 1 X max -maximum conversion observed in one experiment; 2 S 95 -selectivity calculated at X = 95%; 3 R 0 -initial transformation rate.…”

Robust palladium catalysts on nickel foam for highly efficient hydrogenations

“…Examples range from C–C coupling reactions, C–H activations, to transfer and conventional hydrogenations. 1 The superior reactivity, tunable selectivity, and relative stability of Pd under broad-ranging conditions has bolstered its wide-spread adoption by the catalysis and synthetic organic chemistry communities. For example, Pd on carbon (Pd/C) is a standard, bottleable commercial reagent found in most synthetic organic laboratories.…”

Pentacoordinate Al3+ Sites Anchoring Synthesis of Palladium Intermetallic Catalysts on Al2O3 Supports

“…6−10 Another advantage of intermetallic compounds is that their well-defined structures make it possible to investigate the structure−activity relationships. 3,11,12 Nevertheless, the preparation of intermetallic nanoparticles (i-NPs) usually requires high temperatures to overcome the kinetic energy barrier of atomic diffusion and ordering, which frequently accelerates interparticle sintering, 9 especially for Pdbased i-NPs, which are more likely to suffer the sintering issue during high-temperature annealing because of the relatively low Taman temperature of Pd-based alloys. 13 To this end, several strategies have been proposed recently to address the preparation challenges for size control of Pd-based i-NPs, including wet-chemical synthesis with organic capping ligands, 14,15 metal−organic framework-confined coreduction, 16−18 coating with polymer shells, 19 and KCl matrixassisted annealing.…”

“…Supported Pd-based alloy nanoparticles have great potential in many catalytic processes, including selective hydrogenation, biomass conversions, organic coupling reactions, and electrocatalysis of oxygen reduction. − The performance benefit of the alloy system in comparison to the monometallic system originates from the optimization of geometric and electrical structures because of the incorporation of second transition metals. , In particular, constructing the alloy with regular structures (ordered intermetallic compounds) is critical for maximizing their catalytic performance because it allows the production of enhanced geometric or electrical effects. − Another advantage of intermetallic compounds is that their well-defined structures make it possible to investigate the structure–activity relationships. ,, …”