Interfacial effect of Pd supported on mesoporous oxide for catalytic furfural hydrogenation

Design and Application of Mesoporous Catalysts for Liquid-Phase Furfural Hydrogenation

Furfural (FAL), a platform molecule derived from biomass through acid-catalyzed processes, holds significant potential for producing various value-added chemicals. Its unique chemical structure, comprising a furan ring and an aldehyde functional group, enables diverse transformation pathways to yield products such as furfuryl alcohol, furan, tetrahydrofuran, and other industrially relevant compounds. Consequently, optimizing catalytic processes for FAL conversion has garnered substantial attention, particularly in selectivity and efficiency. The liquid-phase hydrogenation of FAL has demonstrated advantages, including enhanced catalyst stability and higher product yields. Among the catalysts investigated, mesoporous materials have emerged as promising candidates because of their high surface area, tunable pore structure, and ability to support highly dispersed active sites. These attributes are critical for maximizing the catalytic performance across various reactions, including FAL hydrogenation. This review provides a comprehensive overview of recent advances in mesoporous catalyst design for FAL hydrogenation, focusing on synthesis strategies, metal dispersion control, and structural optimization to enhance catalytic performance. It explores noble metal-based catalysts, particularly highly dispersed Pd systems, as well as transition-metal-based alternatives such as Co-, Cu-, and Ni-based mesoporous catalysts, highlighting their electronic structure, bimetallic interactions, and active site properties. Additionally, metal-organic frameworks are introduced as both catalysts and precursors for thermally derived materials. Finally, key challenges that require further investigation are discussed, including catalyst stability, deactivation mechanisms, strategies to reduce reliance on external hydrogen sources, and the impact of solvent effects on product selectivity. By integrating these insights, this review provides a comprehensive perspective on the development of efficient and sustainable catalytic systems for biomass valorization.

Efficient Alkyne Semihydrogenation Catalysis Enabled by Synergistic Chemical and Thermal Modifications of a PdIn MOF

Recently, there has been a growing interest in using MOF templating to synthesize heterogeneous catalysts based on metal nanoparticles on carbonaceous supports. Unlike the common approach of direct pyrolysis of PdIn-MOFs at high temperatures, this work proposes a reductive chemical treatment under mild conditions before pyrolysis (resulting in PdIn-QT). The resulting material (PdIn-QT) underwent comprehensive characterization via state-of-the-art aberration-corrected electron microscopy, N2 physisorption, X-ray absorption spectroscopy, Raman, X-ray photoelectron spectroscopy, and X-ray diffraction. These analyses have proven the existence of PdIn bimetallic nanoparticles supported on N-doped carbon. In situ DRIFT spectroscopy reveals the advantageous role of indium (In) in regulating Pd activity in alkyne semihydrogenation. Notably, incorporating a soft nucleation step before pyrolysis enhances surface area, porosity, and nitrogen content compared to direct MOF pyrolysis. The optimized material exhibits outstanding catalytic performance with 96% phenylacetylene conversion and 96% selectivity to phenylethylene in the fifth cycle under mild conditions (5 mmol phenylacetylene, 7 mg cat, 5 mL EtOH, R.T., 1 H2 bar).

Constructing a Pd-Co Interface to Tailor a d-Band Center for Highly Efficient Hydroconversion of Furfural over Cobalt Oxide-Supported Pd Catalysts

Cobalt is an alternative catalyst for furfural hydrogenation but suffers from the strong binding of H and furan ring on the surface, resulting in low catalytic activity and chemoselectivity. Herein, by constructing a Pd-Co interface in cobalt oxide-supported Pd catalysts to tailor the d-band center of Co, the concerted effort of Pd and Co boosts the catalytic performance for the hydroconversion of furfural to cyclopentanone and cyclopentanol. The increased dispersion of Pd on acid etching Co3O4 promotes the reduction of Co3+ to Co0 by enhancing hydrogen spillover, favoring the creation of the Pd-Co interface. Both experimental and theoretical calculations demonstrate that the electron transfer from Pd to Co at the interface results in the downshift of the d-band center of Co atoms, accompanied by the destabilization of H and furan ring adsorption on the Co surface, respectively. The former improves the furfural hydrogenation with TOF on Co elevating from 0.20 to 0.62 s-1, and the latter facilitates the desorption of formed furfuryl alcohol from the Co surface for subsequently hydrogenative rearrangement of the furan ring to cyclopentanone on acid sites. The resultant Pd/Co3O4-6 catalyst delivers superior activity with a 99% furfural conversion and 85% overall selectivity toward cyclopentanone/cyclopentanol. We anticipate that such a concept of tailoring the d-band center of Co via interface engineering provides novel insight and feasible approach for the design of highly efficient catalysts for furfural hydroconversion and beyond.

Recent Progress in Pd-Based Nanocatalysts for Selective Hydrogenation

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.

Hydrogenation of furfural over Pd@ZIF-67 derived catalysts: direct hydrogenation and transfer hydrogenation

Pd particles coated with ZIF-67 (Pd@ZIF-67) was prepared from the self-reduction of palladium acetate.