The Properties of Elasticity, Thermology, and Anisotropy in Pd-Based Alloys

This work is devoted to investigate the elasticity, anisotropy, plastic properties, and thermal conductivity of PdSnYb, PdSn2Yb and Heusler alloy Pd2SnYb via employing the first-principles. The magnetic properties of Pd2SnYb, PdSnYb and PdSn2Yb are obtained by the geometry optimization combining with spin polarization. And the stability of these three kinds of materials is ensured by comparing with the enthalpy of formation and binding energy. The Fermi energy has same trend with stability. The details of bulk and Young’s modulus are demonstrated in 3D plots, embodied the elastic anisotropies of PdSnYb, PdSn2Yb, and Pd2SnYb. The calculations of plastic properties are also anisotropic. And the minimum thermal conductivities are small enough for these three materials to be used as thermal barrier coatings.

Synthesis of amorphous Pd-based nanocatalysts for efficient alcoholysis of styrene oxide and electrochemical hydrogen evolution

Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications,especially in catalysis,as compared with their conventional crystalline counterparts.It is imperative to achieve the controlled preparation of amorphous noble metal-based nanomaterials for the exploration of their phase-dependent applications.Here,we report a facile wet-chemical reduction strategy to synthesize various amorphous multimetallic Pd-based nanomaterials,including PdRu,PdRh,and PdRuRh.The phase-dependent catalytic performances of distinct Pd-based nanomaterials towards diverse catalytic applications have been demonstrated.Specifically,the usage of PdRu nanocatalysts with amorphous and crystalline face-centered cubic(fcc)phases can efficiently switch the ring-opening route of styrene oxide to obtain different products with high selectivity through alcoholysis reaction and hydrogenation reaction,respectively.Moreover,when used as an electrocatalyst for hydrogen evolution reaction(HER),the synthesized amorphous PdRh nanocatalyst exhibits low overpotential and high turnover frequency values,outperforming its crystalline fcc counterpart and most of the reported Pd-based HER electrocatalysts.

Pd-based nanocatalysts for oxygen reduction reaction:Preparation,performance,and in-situ characterization

Electrochemical energy devices such as fuel cells have received extensive concern in recent decades.However,the commercial applications of fuel cells have been restricted by the slow kinetics of oxygen reduction reaction(ORR).Pd-based fuel cell catalysts are strong candidates for enhanced ORR activities,especially under alkaline conditions.Therefore,extensive exploration has been made to improve the performance of Pd-based nano-catalysts for oxygen reduction reaction.This paper reviews the research progress of preparation,electrocatalytic performance,and in-situ characterization of various Pd-based oxygen reduction catalysts,from zero-dimensional nanoparticles,to one-dimensional nanowires,to two-dimensional nanosheets,and to Pd single-atom catalysts.It may provide some help for improving the activity of Pd-based catalysts and understanding the reaction mecha-nisms and structure-activity relationships.

PD-based trajectory tracking control in automatic cell injection system

Trajectory tracking technology has been the focus of industrial manipulatory applications for many years, and its research has been found in micromanipulation in bioengineering recently. In this paper, a hybrid vision and force control method is applied to the automatic cell injection. The three-dimensional cell injection process involves the trajectory tracking in free space and the force control in contact space. A PD plus feedforward compensation control method is applied to the trajectory tracking in 3D space. Further, a PD-based robust controller is introduced into trajectory tracking while the systemic uncertainty of the cell injection is additionally considered. Both of the two control methods are theoretically proved to be exponential convergent. Finally, the effectiveness of the proposed method is verified as compared with other control methods by its application to trajectory tracking problem.

Pd-based nanoporous metals for enzyme-free electrochemical glucose sensors

Nanoporous metals （NPMs） show potential applications as enzyme-free glucose sensors. There are few reports on nanoporous Pd in this area even though their cost is much lower than other NPMs. In this work, we report the formation of Pd-based NPM with improved catalytic activity towards the oxidation of glucose. By dealloying metallic glasses, Pd-based NPMs with hi-continuous networks were obtained. All the Pd-based NPMs show high electrochemical catalytic activity towards glucose oxidation. In this study, NPM with an open, three-dimensional, ligament-channel nanoporous structure resulted by dealloying metallic Pd3oCu4oNiloP2o, producing a pore size of 11 nm and a ligament size of 7 nm as the best configuration towards the direct oxidation reaction of glucose.

AlCl_(3)modified Pd/Al_(2)O_(3)catalyst for enhanced anthraquinone hydrogenation

Anthraquinone hydrogenation to produce H_(2)O_(2) is an economically interesting reaction with great industrial importance.Here,we report a series of Pd/xAl catalysts with different AlCl_(3) contents by a conventional stepwise impregnation method.The optimal Pd/1.0Al catalyst exhibits a higher performance toward anthraquinone hydrogenation with 8.3 g·L^(-1)hydrogenation efficiency,99.5%selectivity and good stability,obviously superior to that of Pd/Al_(2)O_(3) catalyst(5.2 g·L^(-1)and 97.2%).Detailed characterization demonstrates that AlCl_(3) can be grafted on the γ-Al_(2)O_(3) support to obtain a modified support with abundant surface weak acid and Lewis acid,which can adsorb and activate anthraquinone.Meanwhile,its steric hindrance could isolate and disperse active metals to form more active sites.The synergies between metal sites and acid sites promotes the anthraquinone hydrogenation.Furthermore,the good stability after grafting AlCl_(3) could attribute to the enhanced metal-support interaction inhibiting metal particles agglomeration and leaching.

A Pd-metalated porous organic polymer as a highly efficient heterogeneous catalyst for C–C couplings

An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.

Boosting fuel cell catalysis by surface doping of W on Pd nanocubes

The development of active and durable non-Pt electrocatalysts with well-defined microstructure is of great importance to both fuel cell applications and fundamental understanding.Herein,we report a surface-doping process to prepare well-defined W-doped Pd nanocubes with a tunable atomic percent of W from 0 to 1.5%by using the Pd nanocubes as seeds.The obtained 1.2%W-doped Pd nanocubes/C exhibited greatly enhanced electrocatalytic performance toward oxygen reduction reaction in alkaline media,presenting an enhancement factor of 4.7 in specific activity and 2.5 in mass activity compared to the activity of a commercial Pt/C catalyst.The downshift of the d-band center due to a negative charge transfer from W to Pd intrinsically accounts for such improvement in activity by weakening the adsorption of reaction intermediates.Also,the 1.2%W-doped Pd nanocubes/C showed superior catalytic properties for the ethanol oxidation reaction,showing great potential for serving as a bifunctional electrocatalyst in fuel cells.

Laser fragmentation in liquid synthesis of novel palladium-sulfur compound nanoparticles as efficient electrocatalysts for hydrogen evolution reaction

One promising way to tune the physicochemical properties of materials and optimize their performance in various potential applications is to engineer material structures at the atomic level.As is well known,the performance of Pd-based catalysts has long been constrained by surface contamination and their single structure.Here,we employed an unadulterated top-down synthesis method,known as laser fragmentation in liquid(LFL),to modify pristine Pd PS crystals and obtained a kind of metastable palladium-sulfur compound nanoparticles(LFL-Pd S NPs)as a highly efficient electrocatalyst for hydrogen evolution reaction(HER).Laser fragmentation of the layered Pd PS crystal led to a structural reorganization at the atomic level and resulted in the formation of uniform metastable LFL-Pd S NPs.Noteworthy,the LFL-Pd S NPs show excellent electrocatalytic HER performance and stability in acidic media,with an overpotential of-66 m V at 10 m A·cm^(-2),the Tafel slope of 42 m V·dec^(-1).The combined catalytic performances of our LFL-Pd S NPs are comparable to the Pt/C catalyst for HER.This work provides a top-down synthesis strategy as a promising approach to design highly active metastable metal composite electrocatalysts for sustainable energy applications.

Lamellar-assembled PdNi super-nanosheets as effective oxygen redox dual-electrocatalysts for rechargeable Zn-air batteries

Exploration of bifunctional electrocatalysts toward effective oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is pivotal for developing high-efficiency and rechargeable metal-air batteries but remains great challenging.Here we elaborately synthesize lamellar-assembled PdNi super-nanosheets(SNSs)with an optimized Pd/Ni molar ratio to serve as attractive ORR and OER bifunctional electrocatalysts for rechargeable high-powered Zn-air batteries(ZABs).The products are layer-by-layer stackings of ultrathin PdNi nanosheet motifs.On the drastically extended two-dimensional(2D)surface,the inserted Ni atoms can substantially lower down the d-band center of surface Pd toward improved ORR kinetics and concurrently create oxytropic NiOx sites to adsorb–OH groups for promoting the reverse OER electrocatalysis.Specifically,the ORR mass activity and specific activity of the primary Pd_(92)Ni_(8)SNSs attain 2.5 A·mg^(−1)and 3.15 mA·cm^(−2),which are respectively 14 and 9 times those of commercial Pt/C.Meanwhile,the OER activity and stability of Pd_(92)Ni_(8)SNSs/C distinctly outperform those of the RuO_(2)benchmark,suggesting excellent reversible oxygen electrocatalysis.The power density of the ZAB with Pd_(92)Ni_(8)SNSs/C as the air cathode is 2.7 times higher than that by Pt/C benchmark.Significantly,it can last for over 150 h without significant performance degradation during the charge–discharge cycle test.This work showcases a feasible strategy for developing self-assembled multimetallic 2D nanomaterials with excellent bifunctional catalytic performances toward energy conversion applications.

Three-dimensional Pyrenyl Graphdiyne Supported Pd Nanoparticle as an Efficient and Easily Recyclable Catalyst for Reduction of 4-Nitrophenol

The fabrication of highly active and easily recyclable Pd-based catalyst is meaningful for their practical application.Herein,a Pd-based dip-catalyst(Pd@Pyr-GDY)is fabricated on graphdiyne(Pyr-GDY)grown on copper foam,and applied in the reduction of nitroarenes.Specially,the as-formed Pd@Pyr-GDY shows good catalytic performance toward the reduction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP)by NaBH4 with a rate constant k value of 3.84 min^(−1),which is 12-fold higher than that of the commercial Pd/C.More importantly,Pd@Pyr-GDY could be easily and rapidly recovery from the reaction medium and no distinct inactivation was found after six cycles of the reaction.This work presents an easy way to design an efficient and easily recyclable Pd-based catalyst for practical use.

Oxygen modified CoP2 supported palladium nanoparticles as highly efficient catalyst for hydrolysis of ammonia borane

Ammonia borane(AB)is regarded as a promising chemical hydrogen-storage material due to its high hydrogen content,nontoxicity,and long-term stability under ambient temperature.However,constructing advanced catalysts to further promote the hydrogen production still remains a challenge for the hydrolysis of AB.Herein,we report a novel oxygen modified CoP_(2)(O-CoP_(2))material with dispersed palladium nanoparticles(Pd NPs)as a highly efficient and sustainable catalyst for AB hydrolysis.The modification of oxygen could optimize the catalytic synergy effect between CoP_(2)and Pd NPs,achieving enhanced catalytic activity with a turnover frequency(TOF)number of 532 min^(-1)and an activation energy(E_(a))value of 16.79 kJ·mol^(-1).Meanwhile,reaction kinetic experiments prove that the activation of water is the rate-determining step(RDS).The water activation mechanism is revealed by quasi in-situ X-ray photoelectron spectroscopy(XPS)and in-situ X-ray absorption fine structure(XAFS)measurements.The activation of water leads to the production of-H and-OH groups,which are further adsorbed on the oxygen atoms in P-O bond and Pd atoms,respectively.In addition,density functional theory(DFT)calculations indicate that the introduced oxygen facilitates the adsorption and activation of water molecules.This novel modulation strategy successfully sheds new light on the development of advanced catalysts for hydrolysis of AB and beyond.

Molybdenum-doped ordered L1_(0)-PdZn nanosheets for enhanced oxygen reduction electrocatalysis

Ultrathin Pd-based two-dimensional(2D)nanosheets(NSs)with tunable physicochemical properties have emerged as promising candidate for oxygen reduction reaction(ORR).Unfortunately,structurally ordered Pd-based NSs can be hardly prepared as high temperature annealing(>600℃)is necessary for disorder to order phase transition,making it a considerable challenge for morphology control.Herein,a new class of ultrathin structurally ordered Mo-doped L1_(0)-PdZn NSs with curved geometry and abundant defects/lattice distortions is reported as an efficient oxygen reduction electrocatalyst in alkaline solution.It is found that Mo(CO)_(6) serves as reducing agent and Mo source to generate the unique ordered 2D morphology,which leads to the significantly modified electronic structure.The developed L1_(0)-Mo-PdZn NSs exhibit excellent ORR mass activity of 2.6 A mg_(Pd)^(−1) at 0.9 V versus reversible hydrogen electrode,31.5 and 17.6 times higher than those of Pd/C and Pt/C,respectively,outperforming most of the reported Pdbased ORR electrocatalsyts.Impressively,L1_(0)-Mo-PdZn NSs is extremely stable for ORR,with only 2.3% activity loss after 10000 potential cycles.Density functional theory study suggests that ordered L1_(0) structure and Mo doping can raise the vacancy formation energy of Pd atom and thus promote the ORR stability.