Dispersed Palladium Research Articles

The investigation of hydrogen gas sensing properties of SAW gas sensor based on palladium surface modified SnO2 thin film

The sol-gel method and the magnetron sputtering method were used to deposit the SnO2 thin films on 128° YX LiNbO3 piezoelectric substrate for fabricating different kinds of delay-line surface acoustic wave (SAW) hydrogen gas sensors. To improve hydrogen gas sensing performance of SnO2 sensing films, the bi-layer structure sensitive films was used, which was composed of one pure SnO2 layer and one highly dispersed palladium nanoparticle layer. This bi-layer structure evidently enhanced the hydrogen gas sensing properties of SnO2 thin films. The microstructure, surface morphology and composition of as-prepared SnO2 sensitive films were analyzed by XRD, FESEM and XPS. The oscillator circuit with SAW sensor as resonate was designed to transduce the response of sensitive film into the frequency shift of oscillator. One precise temperature control system was used to ensure the temperature stability of SAW device. The Pd-surfaced-modified SnO2 thin film deposited by magnetron sputtering method has the highest frequency shift of 115.9kHz to 2000ppm hydrogen gas at 175°C. The influence of thickness on the morphology of Pd nanoparticles and hydrogen gas sensing performance was studied. The size of Pd nanoparticle increases with thickness of Pd films and too thick Pd layer will reduce the hydrogen gas sensing performance of SnO2 films.

Sapium sebiferum leaf extract mediated synthesis of palladium nanoparticles and in vitro investigation of their bacterial and photocatalytic activities

There is a growing need to introduce eco-friendly and sustainable procedures for the synthesis of metal nanoparticles that include a mild reaction conditions, simple reaction setup, use of nontoxic medium such as water and plant extract, cost effectiveness as well as greater efficiency for biomedical and catalytic applications. For this purpose, small and highly dispersed palladium nanoparticles (PdNPs) were prepared by eco-friendly and cost effective green method using water soluble leaf extract of Sapium sebiferum as a reducing and capping agent. The formation of PdNPs was optimized at various temperatures i.e. (30°C, 60°C and 90°C) and different leaves extract (5mL and 10mL) in order to control their size and shape. The results indicated that PdNPs synthesized at 10mL leaf extract concentration and 60°C temperature have small sized (5nm) and spherical shape. The nanoparticles formation, their dispersion, size and shape were confirmed by various characterization techniques i.e. UV–Vis spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), thermo gravimetric analysis (TGA) and Dynamic light scattering technique (DLS) analysis. The biologically synthesized PdNPs were tested for size dependent photo degradation of methylene blue and inactivation of bacteria. The PdNPs synthesized at optimized condition (10mL extract concentration and 60°C) have strong photo catalytic activity and reduced 90% methylene blue in 70min. The optimized PdNPs also showed strong bacterial inhibition against Staphylococcus aureus 29(±0.8mm), Bacillus subtilis 19(±0.6mm) and pseudomonas aeruginosa 11(±0.6mm). The results of this examination demonstrate effective applications of extremely active PdNPs.

Low-Overpotential Li-O2 Battery: An Application of Nanostructured Cathode Architecture By Atomic Layer Deposition

Li-O2 battery was first reported in 1996, and makes remarkable progress in the recent years with the improvement of technique and knowledge. It has also received significant attention during the past several years due to its extremely high theoretical energy density, which is about 10 times than the commercial Li-ion batteries and comparable with gasoline. However, its sluggish kinetics, which usually results large voltage polarization and low efficiency, hinders the practical applications in commercialized devices. It is generally accepted that various factors, such as the nature, morphology, and surface area of the catalysts, influence the electrochemical reactions in Li-O2 battery. Therefore, it has become an emerging topic to design efficient catalysts which could facilitate the electrochemical reactions. Carbonate-based electrolyte was widely applied in Li-O2 battery system. However, its instability under O2 is one of the major reasons of the poor performance reported previously. Ether-based electrolyte (e.g. TEGDME) is currently broadly employed to reduce the electrolyte decomposition and benefit the catalytic performance, due to the relatively stability under O2 and high potential. However, the decomposition is still observed, even at the charge potential as low as 3.5 V, which may result from reactions of the electrolyte with defect sites on the porous carbon surface. It is reasonable to expect that the electrolyte decomposition would be significantly reduced by a decrease in the surface defect sites. Our previous study reported a reduction in charge overpotential to 0.2 V by an alumina atomic layer deposition (ALD) on porous carbon surface which prevents electrolyte decomposition on carbon surface. By taking advantage of the difference in surface reaction rate, ALD technique can provide selectively deposition of the coating materials onto the targeted surface. Accordingly, the cathode based on the passivation layer architecture shows promising results for solving the charge overpotential problem by passivating the surface defect sites. Here we describe an approach based on a cathode architecture that has a protective ZnO coating passivation layer on a porous carbon substrate. Bulk ZnO has a direct band gap of 3.3 eV, much smaller than that of bulk Al2O3 (8.8 eV). ZnO ALD using alternating exposures to diethylzinc and water is well understood and provides conformal coatings. In addition, the growth rate of Pd is faster on the ZnO surface than the Al2O3 surface. All the above advantages make ZnO a promising material as the passivating layer on carbon. In this study, we demonstrated that a cathode architecture with uniformly dispersed palladium nanoparticles onto a ZnO-passivated porous carbon substrate prepared by ALD shows high electrochemical catalytic activity in Li-O2 battery. Transmission electron microscopy (TEM) showed discrete crystalline nanoparticles decorating the surface of the ZnO-passivated porous carbon support in which the size could be controlled in the range of 3–6 nm, depending on the number of Pd ALD cycles performed. X-ray absorption spectroscopy (XAS) at the Pd K-edge revealed that the carbon-supported Pd existed in a mixed phase of metallic palladium and palladium oxide. The ZnO-passivated layer effectively blocks the defect sites on the carbon surface, minimizing the electrolyte decomposition. As a result, this cathode architecture reduced the charge overpotential to almost 0 V, which is the lowest ever reported. The discharge products are characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of the Pd loading on the electrochemical performance of the Li-O2 cell is also investigated. Our results not only show promising results for solving the charge overpotential problem, and provide the basis for future development of lithium-oxygen cathode materials that can be used to improve the efficiency and to extend cycle life.

Facile synthesis of palladium nanoparticles supported on silica: An efficient phosphine-free heterogeneous catalyst for Suzuki coupling in aqueous media

A convenient one-step method for synthesizing highly dispersed palladium nanoparticles supported on silica, without taking assistance from any external reductant or stabilizer, has been developed. The supported nanoparticles were characterized by N2-adsorption desorption, XRD, HRTEM, SEM-EDX, XPS, ICP analyses and applied as catalyst for Suzuki-Miyaura reactions of aryl halides. The reactions with aryl bromides were performed in neat water at room temperature; while the reactions with aryl chlorides were conducted in aqueous-ethanol at 90°C. The catalyst could be reused at least three times without compromising with its activity, however from the fourth cycle a progressive decrease in yield was noticed. No aggregation of NPs was observed by the TEM analysis of the six-time used catalyst.

Refinery oil upgrading under methane environment over PdOx/H-ZSM-5: Highly selective olefin cyclization

Olefin content minimization is critical for the long-term storage and long-distance transportation of oil product, which is commonly achieved through hydrogen saturation at high pressure to form paraffin. In this study, a novel catalytic process is reported to convert olefin to cycloalkane under methane environment with high selectivity. The main components of the product oil collected over Pd/ZSM-5 catalysts during olefin model compound (i.e., 1-decene) upgrading are cyclopentane, 1-methylbutyl- and cyclopentane, hexyl- while there are more than 46 species identified in the liquid product from the run with H-ZSM-5 support engaged. The total selectivity of the aforementioned cycloalkane products is up to 91.3% when 0.27wt% Pd/ZSM-5 catalyst is charged, thus making the product oil more profitable. The HRTEM and XPS data reveal that the highly dispersed palladium particles are in the form of PdOx. The results from pyridine FT-IR and NH3-TPD indicate that these PdOx species anchored onto the surface acidic sites exhibit the moderate acidic feature of Lewis acidic sites, which enhances the formation and stabilization of carbenium ion intermediates generated from 1-decene cracking. The strong interaction between PdOx species and surface acidic sites could not only stabilize the particle size and modify the electronic structure of Pd species but also modulate the acidic properties of ZSM-5 support, leading to promoted methane activation which would not only release sufficient hydrogen donors for preventing olefin aromatization, but also inhibit the over-cracking of carbenium ions. As a result, the selectivity of catalyst assisted olefin cyclization under methane environment is greatly enhanced.

Nanostructured Cathode Architecture By Atomic Layer Deposition for Improving Performance of Li-O2 Battery

Due to its extremely high theoretical energy density among all the existing energy storage systems, Li-O2 battery has received significant interest since it was firstly reported in 1996. However, its sluggish kinetics, especially during the oxygen evolution reactions, usually results large voltage polarization and low efficiency, and therefore hinders its practical applications in commercialized devices. There are various factors influencing the electrochemical reactions in Li-O2 battery, such as the nature, morphology, and surface area of the catalysts. Therefore, designing efficient catalysts which could facilitate the electrochemical reactions have become an emerging topic. Some of the early work was based on carbonate electrolytes, which have been found unstable against the active anion such as O2 2- and O2 -, leading to the decomposition of the electrolytes. The electrolyte decomposition could also result a high charge potential and lead to the possible formation of Li2CO3. To reduce the electrolyte decomposition and benefit the catalytic performance, ether-based electrolyte (e.g. TEGDME) is currently widely employed in the study of Li-O2battery due to the relatively stability under high potential. However, the decomposition is still observed, even at the charge potential as low as 3.5 V, which may result from reactions of the electrolyte with defect sites on the porous carbon surface. It is reasonable to expect that the electrolyte decomposition would be significantly reduced by a decrease in the surface defect sites. Our previous study[1] reported a reduction in charge overpotential to 0.2 V by an alumina atomic layer deposition (ALD) on porous carbon surface which prevents electrolyte decomposition on carbon surface. By taking advantage of the difference in surface reaction rate, ALD technique can provide selectively deposition of the coating materials onto the targeted surface. Accordingly, the cathode based on the passivation layer architecture shows promising results for solving the charge overpotential problem by passivating the surface defect sites. Here we describe an approach based on a cathode architecture that has a protective ZnO coating passivation layer on a porous carbon substrate. Bulk ZnO has a direct band gap of 3.3 eV, much smaller than that of bulk Al2O3 (8.8 eV). ZnO ALD using alternating exposures to diethylzinc and water is well understood and provides conformal coatings. In addition, the growth rate of Pd is faster on the ZnO surface than the Al2O3 surface. All the above advantages make ZnO a promising material as the passivating layer on carbon. In this study, we demonstrated that a cathode architecture with uniformly dispersed palladium nanoparticles onto a ZnO-passivated porous carbon substrate prepared by ALD shows high electrochemical catalytic activity in Li-O2 battery. Transmission electron microscopy (TEM) showed discrete crystalline nanoparticles decorating the surface of the ZnO-passivated porous carbon support in which the size could be controlled in the range of 3–6 nm, depending on the number of Pd ALD cycles performed. X-ray absorption spectroscopy (XAS) at the Pd K-edge revealed that the carbon-supported Pd existed in a mixed phase of metallic palladium and palladium oxide. The ZnO-passivated layer effectively blocks the defect sites on the carbon surface, minimizing the electrolyte decomposition. As a result, this cathode architecture reduced the charge overpotential to almost 0 V, which is the lowest ever reported. The discharge products are characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of the Pd loading on the electrochemical performance of the Li-O2 cell is also investigated. Our results not only show promising results for solving the charge overpotential problem, and provide the basis for future development of lithium-oxygen cathode materials that can be used to improve the efficiency and to extend cycle life. Figure 1

Photochemical route for synthesizing atomically dispersed palladium catalysts

Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium-titanium oxide catalyst (Pd1/TiO2) on ethylene glycolate (EG)-stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%. The Pd1/TiO2 catalyst exhibited high catalytic activity in hydrogenation of C=C bonds, exceeding that of surface Pd atoms on commercial Pd catalysts by a factor of 9. No decay in the activity was observed for 20 cycles. More important, the Pd1/TiO2-EG system could activate H2 in a heterolytic pathway, leading to a catalytic enhancement in hydrogenation of aldehydes by a factor of more than 55.

Palladium Nanoparticles Supported on a Porous Organic Polymer: An Efficient Catalyst for Suzuki‐Miyaura and Sonogashira Coupling Reactions

AbstractA new porous organic polymer (POP) with high thermal stability and large surface area has been synthesized and applied in the preparation of Pd/POP catalyst. Pd/POP was characterized by XRD, TGA, SEM and TEM. The catalyst consists of highly dispersed palladium nanoparticles of 0.9–4 nm size on POP with a large surface area of 650 m2/g. It presents high catalytic activity for Suzuki‐Miyaura and Sonogashira reactions. The catalyst was reusable for three to five times without significant loss of activity.

Palladium–Polypyrrole Nanocomposites Pd@PPy for Direct C–H Functionalization of Pyrroles and Imidazoles with Bromoarenes

Palladium–polypyrrole nanocomposites (Pd@PPy) with unique combination of high palladium dispersion (nanoparticle size 2.4 nm) and high palladium content (35 wt%) are efficient catalysts for the selective arylation of substituted pyrroles and imidazoles with either activated or deactivated aryl bromides. The performances of the recoverable supported palladium catalyst matches the best performances of homogeneous systems based on Pd(OAc)2 at 0.5–0.2 mol%, and largely overwhelm the classical Pd/C catalyst.

Palladium nanoparticles confined within ZSM-5 zeolite with enhanced stability for hydrogenation of p-nitrophenol to p-aminophenol

High dispersed palladium nanoparticles with the size of about 3.8nm confined within ZSM-5 zeolite catalyst (Pd/ZSM-5-IS) was successfully synthesized by in situ synthesis method based on azeotropic distillation assisted fabrication. Liquid phase selective hydrogenation of p-nitrophenol (PNP) to p-aminophenol (PAP) was chosen as model reactions to evaluate the catalytic behavior of the Pd/ZSM-5 catalysts. Thiophene and 4,6-dimethyldibenzothiophene were used as poisons to test their anti-poisoning ability. Pd/ZSM-5-IS catalyst exhibited higher catalytic activity in hydrogenation of PNP to PAP than sample prepared by impregnation method (Pd/ZSM-5-IM), which was mainly attributed to entering of Pd nanoparticles into the intracrystalline mesovoids of the ZSM-5 support for in situ method efficiently prevent active sites from loss and aggregation. In addition, Pd/ZSM-5-IS catalyst not only maintained high activity for five consecutive runs, but also showed high sulfur tolerance for the hydrogenation reactions. This simple and versatile method also can be extended to cover many kinds of other supported catalysts for broad applications in many other catalytic reactions in the future.

Surface reactivity and self-oscillating oxidation of butan-2-ol over palladium loaded AlPO4

Palladium loaded AlPO4 catalysts were synthesised and characterised by XRD, IR, UV–vis spectroscopy, temperature programmed desorption (TPD) and temperature programmed surface reaction (TPSR). The Pd2+ ions of the dispersed palladium on the amorphous surface of AlPO4 are in D4h symmetry. They can partially be reduced into Pd0 even in dynamic conditions by a mixture of butan-2-ol and oxygen. TPD/TPSR showed that the active sites are formed by the couple PdO/Pd. The presence of PdO on the surface favours the production of methyl ethyl ketone (MEK). The CO2 formation was never observed below 100°C. Moreover, desorption of the MEK takes place in two waves arising from two different types of sites. Only the reactivity of the first set of sites which are located around 80°C was considered in the present study. As a matter of fact, the oxidation of butan-2-ol into MEK (<1.3%) at 74.2°C describes a counter-clockwise hysteresis attributed to a bistability induced by the competition between the redox processes that the surface and the reagents undergo. This sensibility of the catalyst to the parameters governing the reaction resulted in an oscillating oxidation of butan-2-ol. Spontaneous oscillations of the MEK production (αone) appear around 85°C and stop before 100°C. Oscillations of the temperature of the catalyst bed were also recorded but their amplitude never exceeds 7°C. An oscillatory regime appears also for butan-2-ol pressures ranging from 0.61 to 1.65kPa and for a total flow rate between 80 and 260mLmin−1. The oscillating oxidation of butan-2-ol is accompanied by a significant enhancement of the methyl ethyl ketone production.

Surface engineering and palladium dispersion in MCM-41 for methane oxidation

Highly dispersed palladium oxide nanoparticles (Ø∼2nm) were obtained in mesostructured silica of MCM-41 type from divalent palladium complexes tethered from grafted propylamine ligands themselves highly dispersed using a surface engineering approach based on a molecular stencil patterning technique (MSP). A partial surface coverage obtained by incomplete extraction of the surfactant produces a self-assembled and patterned molecular mask that is fixed by silanol capping. After removal of the masking surfactant, the unreacted silanol groups are reacted with 3-(aminopropyl) trimethoxysilane ligands, which are further metallated using an acetonitrile solution of palladium trifluoroacetate Pd(O2CCF3)2. Then, calcination yields PdO nanoparticles of ca. 2 or 6nm depending of the masking percentage of the surface. In some case, calcination was accompagnied by a partial collapse that is undergone by the structure. The structural and textural characteristics of these materials were studied by means of different physico-chemical techniques such as XRD, N2 sorption isotherms, TGA, elemental analysis (EA) by ICP, 29Si-NMR, UV–visible, FT-IR, and Raman spectroscopies. Light-off reactivity curves of methane combustion reveals that these catalysts possess no external PdO phase and follow the gold rule of higher activity for higher active phase dispersion. Eventually, intermediate structural collapse that decreases the molecular diffusion limitation may invert this tendency.

A new insight into the effects of barium addition on Pd-only catalysts: Pd-support interface and CO + NO reaction pathway

The effects of barium addition on both fresh and aged Pd/Ce0.5Zr0.5O2 catalysts were investigated. The activities of the catalysts were evaluated by CO+NO reaction and oxygen storage capacity (OSC). The features of palladium species and the properties of the supports were explored by X-ray diffraction (XRD), nitrogen physisorption, high-resolution TEM, CO chemisorption, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). The adsorption of CO and NO species during the reaction was especially characterized using in situ DRIFTs. The results reveal that barium addition decreases the activity of palladium on Ce0.5Zr0.5O2, especially after ageing. During the ageing, barium reacts with Ce0.5Zr0.5O2 forming barium zirconium oxides (xBaO·yZrO2), which results in a barrier layer at the interface between palladium and ceria-zirconia. Such a layer consumes the beneficial Pd–ceria interface and blocks the migration of activated oxygen supplied from Ce0.5Zr0.5O2 support to palladium, which results in the severe sintering of palladium during ageing and decreases the catalytic activity of the catalysts. In contrast, the activity of Pd/Al2O3 catalysts is improved by barium addition. The barium addition significantly suppresses the sintering of alumina, improves the dispersion of palladium and facilitates the adsorption of active surface nitrates during the reaction.

Highly Dispersed Palladium on Carbon Nanofibers for Hydrogenation of Nitrocompounds to Amines

The effect of palladium dispersion and nature of the support on catalytic performance in hydrogenation of nitrobenzene to aniline was studied. It was shown that the type of the support and modification of palladium with phosphorus make it possible to stabilize highly dispersed (1.5-2 nm) palladium particles in the metallic state, thus increasing the efficiency of new catalysts.

Selective Hydrogenation of Phenol Catalyzed by Palladium on High-Surface-Area Ceria at Room Temperature and Ambient Pressure

Palladium supported on high-surface-area ceria effectively catalyzes the hydrogenation of phenol to cyclohexanone at atmospheric pressure and room temperature. Activation of H2 at Pd sites and phenol at surface ceria sites was investigated by probing the redox properties of the catalyst and studying the mechanism of phenol adsorption. Temperature-programmed reduction and pulsed chemisorption were used to examine the effects of prereduction temperature on catalyst dispersion and reducibility. A sharp effect of prereduction temperature on catalytic activity was observed. This dependence is rationalized as a result of interactions between palladium and ceria, which under reducing conditions enhance palladium dispersion and create different types of environments around the Pd active sites and of encapsulation of the catalyst caused by support sintering at high temperatures. Temperature-programmed diffuse reflectance infrared Fourier transform spectroscopy revealed that phenol undergoes dissociative adsorption...

Metal–Inorganic–Organic Matrices as Efficient Sorbents for Hydrogen Storage

Stabilization of metal nanoparticles (MNPs) without re-aggregation is a major challenge. An unprecedented strategy is developed for achieving high dispersion of copper(0) or palladium(0) on montmorillonite-supported diethanolamine or thioglycerol. This results in novel metal-inorganic-organic matrices (MIOM) that readily capture hydrogen at ambient conditions, with easy release under air stream. Hydrogen retention appears to involve mainly physical interactions, slightly stronger on thioglycerol-based MIOM (S-MIOM). Thermal enhancement of desorption suggests also a contribution of chemical interactions. The increase of hydrogen uptake with prolonged contact times arises from diffusion hindrance, which appears to be beneficial by favoring hydrogen entrapment. Even with compact structures, MIOMs act as efficient sorbents with much higher efficiency factor (1.14-1.17 mmol H 2 m(-2)) than many other sophisticated adsorbents reported in the literature. This opens new prospects for hydrogen storage and potential applications in microfluidic hydrogenation reactions.

The First Example of ortho-Arylation of Benzamides over Pd/Mesoporous Silica: A Novel Approach for Direct sp2 C–H Bond Activation

Three-dimensional mesoporous silica with a highly dispersed palladium nanoparticles composite (PS-3) catalyst has been prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, nitrogen sorption, and high resolution transmission electron microscopy. The PS-3 catalyst utilized for the first time as an efficient and reusable catalyst in the ortho-arylation of benzamides by aryl iodides has been demonstrated with the simplest amide CONH2 as a directing group. It can be successfully applied to various benzamides and aryl iodides with both electron donating and withdrawing groups. The catalyst can be simply recovered and reused several times without significant loss in catalytic activity.

Palladium Supported on Mesoporous Silica via a Two-Step Method as an Efficient Catalyst for Suzuki-Miyaura Coupling Reactions

In this paper, palladium-containing SBA-15 (Pd/SBA-15) was synthesized via a two-step method. In this procedure, Pd nanoparticles of 3-5 nm in size have been synthesized by formalin reduction method and incorporated into mesoporous SBA-15 silica during hydrothermal synthesis. The resulting nanocomposite with 1.20 wt% Pd loading was achieved with highly dispersed and uniform palladium nanoparticles. The catalytic activity of the Pd/SBA-15 nanocomposite was used as a catalyst for the Suzuki-Miyaura coupling reactions. The Pd/SBA-15 nanocomposite exhibited excellent catalytic activities and reuse ability in air for the Suzuki-Miyaura coupling reactions.

Low-temperature carbon monoxide oxidation catalysed by regenerable atomically dispersed palladium on alumina.

Catalysis by single isolated atoms of precious metals has attracted much recent interest, as it promises the ultimate in atom efficiency. Most previous reports are on reducible oxide supports. Here we show that isolated palladium atoms can be catalytically active on industrially relevant γ-alumina supports. The addition of lanthanum oxide to the alumina, long known for its ability to improve alumina stability, is found to also help in the stabilization of isolated palladium atoms. Aberration-corrected scanning transmission electron microscopy and operando X-ray absorption spectroscopy confirm the presence of intermingled palladium and lanthanum on the γ-alumina surface. Carbon monoxide oxidation reactivity measurements show onset of catalytic activity at 40 °C. The catalyst activity can be regenerated by oxidation at 700 °C in air. The high-temperature stability and regenerability of these ionic palladium species make this catalyst system of potential interest for low-temperature exhaust treatment catalysts.

Palladium Nanoparticles Supported on Magnesium Hydroxide Fluorides: A Selective Catalyst for Olefin Hydrogenation

AbstractA one‐pot synthesis of palladium nanoparticles supported on magnesium hydroxide fluoride has been performed with the fluorolytic sol–gel method. The prepared catalysts were characterized by using various physicochemical techniques. The sol–gel method led to high surface area (&gt;135 m2 g−1), mesoporous catalysts (pore volume=0.19–0.23 cm3 g−1, pore diameter=3–5 nm) with uniformly dispersed palladium nanoparticles approximately 2 nm in diameter on the surface. The catalysts synthesized by using different concentrations of aqueous hydrofluoric acid exhibited changing surface and acidic properties. Very high dispersion of palladium on magnesium fluoride (47 %) was obtained with 1 wt % palladium loading. The catalysts were used for hydrogenation of various olefins in the presence of other organic functionalities at room temperature and atmospheric hydrogen pressure. Various substituted olefins were hydrogenated with almost 100 % conversion and selectivity. The catalysts were recycled efficiently over five cycles without appreciable loss in catalytic activity. There was no palladium leaching under the reaction conditions, which was confirmed by inductively coupled plasma atomic emission spectroscopy analysis. Activation of olefin on the catalyst surface could not be observed by in situ FTIR studies, indicating facile activation of hydrogen on the palladium supported on magnesium hydroxide fluoride.