Surface chemistry and catalysis studies on the palladium-boron system in the semihydrogenation of alkynes

Krawczyk, M.; Sobczak, Janusz W.; Palczewska, W.

doi:10.1007/bf00763923

Cited by 16 publications

(11 citation statements)

References 13 publications

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“…These may include surface electronic effects, interstitial electronic effects and selective site blockage by the boron modification. Krawczyk et al 37 studied the effect of surface B (borides and borates) in the hydrogenation of alkynes. They observed a degree of promoted alkene selectivity over alkane products by boron adspecies, which suggests that a selective surface blockage mechanism can be taken place.…”

Section: Resultsmentioning

confidence: 99%

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

et al. 2014

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Lindlar catalysts comprising of palladium/calcium carbonate modified with lead acetate and quinoline are widely employed industrially for the partial hydrogenation of alkynes. However, their use is restricted, particularly for food, cosmetic and drug manufacture, due to the extremely toxic nature of lead, and the risk of its leaching from catalyst surface. In addition, the catalysts also exhibit poor selectivities in a number of cases. Here we report that a non-surface modification of palladium gives rise to the formation of an ultra-selective nanocatalyst. Boron atoms are found to take residence in palladium interstitial lattice sites with good chemical and thermal stability. This is favoured due to a strong host-guest electronic interaction when supported palladium nanoparticles are treated with a borane tetrahydrofuran solution. The adsorptive properties of palladium are modified by the subsurface boron atoms and display ultra-selectivity in a number of challenging alkyne hydrogenation reactions, which outclass the performance of Lindlar catalysts.

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Section: Resultsmentioning

confidence: 99%

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

et al. 2014

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“…In general, boron interacting with metals can lead to a variety of interesting phenomena, such as alloy ultrahardening, 16 emergence of topological and Kondo insulators, 17 exotic magnetism, 18 surface reconstructions, 19 record coordination chemistry, 20 and the selectivity of Pd catalysts in hydrogenation. 21,22 Recently, we began to theoretically probe boron as a dopant for small Pt clusters deposited on magnesia, 23 and found it to reduce affinities of these systems to carbon atoms. Building from this promising initial result, we now address the effect of boration on the selectivity of catalytic dehydrogenation and coking sensitivity of Pt 7 on alumina, using both ab initio and statistical mechanical theory, in conjunction with experiment.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Alloying Pt with Sn and Zn , has been used for selectivity control and with Pd to reduce sintering. , Here, our inspiration is drawn from the boration (boron-doping) of extended surfaces of Co and Ni, used in Fischer–Tropsch synthesis and steam methane reforming, respectively. , Boration of these metal surfaces extended the lifetime of the catalyst by preventing coke adsorption. In general, boron interacting with metals can lead to a variety of interesting phenomena, such as alloy ultrahardening, emergence of topological and Kondo insulators, exotic magnetism, surface reconstructions, record coordination chemistry, and the selectivity of Pd catalysts in hydrogenation. , Recently, we began to theoretically probe boron as a dopant for small Pt clusters deposited on magnesia, and found it to reduce affinities of these systems to carbon atoms. Building from this promising initial result, we now address the effect of boration on the selectivity of catalytic dehydrogenation and coking sensitivity of Pt 7 on alumina, using both ab initio and statistical mechanical theory, in conjunction with experiment.…”

Section: Introductionmentioning

confidence: 99%

Boron Switch for Selectivity of Catalytic Dehydrogenation on Size-Selected Pt Clusters on Al₂O₃

et al. 2017

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Size--selected supported clusters of transition metals can be remarkable and highly tunable catalysts. A par--ticular example is Pt clusters deposited on alumina, which have been shown to dehydrogenate hydrocarbons in a size--specific manner. 1 Pt 7 , of the three sizes studied, is the most active and therefore like many other catalysts, deactivates by coking during reactions in hydrocarbon--rich environments. Using a combination of experiment and theory, we show that nano--alloying Pt 7 with boron modifies the alkene--binding affinity to reduce coking. From a fundamental perspective, the comparison of experimental and theoretical results shows the importance of considering not simply the most stable clus--ter isomer, but rather the ensemble of accessible structures as it changes in response to temperature and reagent cover--age.

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“…Recently, there has been a growing interest in the use of nonmetal elements to promote the catalytic capability of metal nanocrystals. 6−13 Boron-doped palladium (B-Pd) has been shown to exhibit versatile catalytic capabilities for reactions such as the hydrogenation of alkyne, 14,15 furfural hydrogenation, 16 H 2 production, 17,18 the electro-oxidation of ethanol and formic acid, 19−21 and oxygen reduction. 22,23 In considering the structure−property relationship, one of the urgent challenges in extending the applications of B-Pd catalysts is to develop a simple and facile route that enables precise control of boron doping in palladium over a wide range.…”

Section: ■ Introductionmentioning

confidence: 99%

Controllable Increase of Boron Content in B-Pd Interstitial Nanoalloy To Boost the Oxygen Reduction Activity of Palladium

Chen

Wang

et al. 2017

Chem. Mater.

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Boron doping can boost the catalytic activity of palladium for diverse reactions. Precise control of the doping content is crucial but remains difficult in current synthesis, which generally involves the use of instable and costly borane-organic compounds. Herein, by taking advantage of the relatively strong solvation of N,N-dimethylformamide (DMF) to Na+ and the increased stability BH4 – in DMF, we synthesize B-Pd interstitial nanocrystals in DMF, with NaBH4 acting as a reductant and boron source. The boron content, which can be readily tuned by changing the reaction time and NaBH4 concentration, can reach up to 20 at. %. Such a high boron doping results in a great beneficial effect on the catalytic capability of Pd toward the oxygen reduction reaction (ORR). The synthesized B-Pd nanoalloy exhibits a mass and specific activity for ORR that are, respectively, ca. 14 and 14.6 times higher than those of the state-of-the-art commercial Pt catalyst in alkaline solution. Density functional theory (DFT) calculations reveal three types of surface sites that are responsible for the enhanced activity, namely, Pd-BO2 assemblies, Pd atoms neighbored by the assemblies, and the Pd atoms modified with subsurface B atoms. The Pd-BO2 assembly has a Pt-like activity, while the neighboring Pd-BO2 assembly and subsurface B-modified Pd atoms could catalyze ORR much more efficiently than Pt. The facile and controllable boron doping in palladium should strengthen the power of Pd-based catalysts and, therefore, provides great prospects for their widespread application.

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Surface chemistry and catalysis studies on the palladium-boron system in the semihydrogenation of alkynes

Cited by 16 publications

References 13 publications

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

Boron Switch for Selectivity of Catalytic Dehydrogenation on Size-Selected Pt Clusters on Al₂O₃

Controllable Increase of Boron Content in B-Pd Interstitial Nanoalloy To Boost the Oxygen Reduction Activity of Palladium

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Surface chemistry and catalysis studies on the palladium-boron system in the semihydrogenation of alkynes

Cited by 16 publications

References 13 publications

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation

Boron Switch for Selectivity of Catalytic Dehydrogenation on Size-Selected Pt Clusters on Al2O3

Controllable Increase of Boron Content in B-Pd Interstitial Nanoalloy To Boost the Oxygen Reduction Activity of Palladium

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Boron Switch for Selectivity of Catalytic Dehydrogenation on Size-Selected Pt Clusters on Al₂O₃