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 ...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.展开更多
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 ...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.展开更多
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 imp...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.展开更多
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 react...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.展开更多
Hydrogen peroxide(H_(2)O_(2))is a green oxidant that has been widely used.The direct synthesis of hydrogen peroxide(DSHP)offers significant advantages in terms of high atomic economy and environmentally friendly effec...Hydrogen peroxide(H_(2)O_(2))is a green oxidant that has been widely used.The direct synthesis of hydrogen peroxide(DSHP)offers significant advantages in terms of high atomic economy and environmentally friendly effects.However,due to the inevitable side reactions and severe mass transfer limitations,it is still challenging to balance the selectivity and activity for the DSHP.Combining theoretical understanding with the controllable synthesis of nanocatalysts may significantly facilitate the design of“dream catalysts”for the DSHP.In this work,the main factors affecting the reaction performance of catalysts and the active sites of catalysts have been reviewed and discussed in detail.The development and design of catalysts with high efficiency were introduced from three aspects:the catalyst support,active component and atomic impurity.In addition,the coupling of DSHP and other oxidation reactions to realize one-pot in situ oxidation reactions was comprehensively emphasized,which showed essential guiding significance for the future development of H_(2)O_(2).展开更多
Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment...Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment modulation strategy was used to construct the nitrogen-doped hollow carbon sphere encapsulated with Pd(Pd@NHCS-X,X:600–800)nanoreactors for catalytic HDO of biomass-derived vanillin in water.The specific surface microenvironments of Pd@NHCS catalysts including the electronic property of active Pd centers and the surface wettability and porous structure of NHCS supports could be well-controlled by the calcination temperature of catalysts.Intrinsic kinetic evaluations demonstrated that the Pd@NHCS-600 catalyst presented a high turnover frequency of 337.77 h^(–1)and a low apparent activation energy of 18.63 kJ/mol.The excellent catalytic HDO performance was attributed to the unique surface microenvironment of Pd@NHCS catalyst based on structure-performance relationship analysis and DFT calculations.It revealed that pyridinic N species dominated the electronic property regulation of Pd sites through electronic metal-support interaction(EMSI)and produced numerous electron-rich active Pd centers,which not only intensified the dissociation and activation of H2 molecules,but also substantially improved the activation capability of vanillin via the enhanced adsorption of–C=O group.The fine hydrophilicity and abundant porous structure promoted the uniform dispersion of catalyst and ensured the effective access of reactants to catalytic active centers in water.Additionally,the Pd@NHCS-600 catalyst exhibited excellent catalytic stability and broad substrate applicability for the selective aqueous phase HDO of various biomass-derived carbonyl compounds.The proposed surface microenvironment modulation strategy will provide a new consideration for the rational design of high-performance nitrogen-doped carbon-supported metal catalysts for catalytic biomass transformation.展开更多
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 Su...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.展开更多
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 proc...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.展开更多
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...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.展开更多
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 perfor...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.展开更多
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...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.展开更多
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 b...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.展开更多
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 ...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.展开更多
文摘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.
基金supported by the National Science Foundation of China(Nos.51001026,21173041)the Project-sponsored by SRF for ROCS,SEM(No.6812000013)+2 种基金the Project-sponsored by Nanjing for ROCS(No.7912000011)Opening Project of Jiangsu Key Laboratory of Advanced Metallic Materials(No.AMM201101)the Fundamental Research Funds for the Central Universities(Nos.3212002205,3212003102)
文摘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.
基金H.Z.thanks the support from ITC via the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM),the Research Grants Council of Hong Kong(No.11301721)the Start-Up Grant(No.9380100)the grants(No.1886921)from the City University of Hong Kong.This research used 7-BM of the National Synchrotron Light Source II,a U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract(No.DE-SC0012704).
文摘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.
基金National Key Research and Development Program of China(2020YFB1505800)National Natural Science Foundation of China(21925404,21972117,22122205,and 22021001)+1 种基金the Central Guidance on Local Science and Technology Development Fund of Shenzhen(2021Szvup065)the State Key Laboratory of Fine Chemicals(KF2002).
文摘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.
基金This work is supported by the National Key R&D Program of China(2021YFB3801600)the National Natural Science Foundation of China(22078005).
文摘Hydrogen peroxide(H_(2)O_(2))is a green oxidant that has been widely used.The direct synthesis of hydrogen peroxide(DSHP)offers significant advantages in terms of high atomic economy and environmentally friendly effects.However,due to the inevitable side reactions and severe mass transfer limitations,it is still challenging to balance the selectivity and activity for the DSHP.Combining theoretical understanding with the controllable synthesis of nanocatalysts may significantly facilitate the design of“dream catalysts”for the DSHP.In this work,the main factors affecting the reaction performance of catalysts and the active sites of catalysts have been reviewed and discussed in detail.The development and design of catalysts with high efficiency were introduced from three aspects:the catalyst support,active component and atomic impurity.In addition,the coupling of DSHP and other oxidation reactions to realize one-pot in situ oxidation reactions was comprehensively emphasized,which showed essential guiding significance for the future development of H_(2)O_(2).
文摘Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment modulation strategy was used to construct the nitrogen-doped hollow carbon sphere encapsulated with Pd(Pd@NHCS-X,X:600–800)nanoreactors for catalytic HDO of biomass-derived vanillin in water.The specific surface microenvironments of Pd@NHCS catalysts including the electronic property of active Pd centers and the surface wettability and porous structure of NHCS supports could be well-controlled by the calcination temperature of catalysts.Intrinsic kinetic evaluations demonstrated that the Pd@NHCS-600 catalyst presented a high turnover frequency of 337.77 h^(–1)and a low apparent activation energy of 18.63 kJ/mol.The excellent catalytic HDO performance was attributed to the unique surface microenvironment of Pd@NHCS catalyst based on structure-performance relationship analysis and DFT calculations.It revealed that pyridinic N species dominated the electronic property regulation of Pd sites through electronic metal-support interaction(EMSI)and produced numerous electron-rich active Pd centers,which not only intensified the dissociation and activation of H2 molecules,but also substantially improved the activation capability of vanillin via the enhanced adsorption of–C=O group.The fine hydrophilicity and abundant porous structure promoted the uniform dispersion of catalyst and ensured the effective access of reactants to catalytic active centers in water.Additionally,the Pd@NHCS-600 catalyst exhibited excellent catalytic stability and broad substrate applicability for the selective aqueous phase HDO of various biomass-derived carbonyl compounds.The proposed surface microenvironment modulation strategy will provide a new consideration for the rational design of high-performance nitrogen-doped carbon-supported metal catalysts for catalytic biomass transformation.
基金supported by the National Natural Foundation of China(21422306,21203165,21403193)the Fundamental Research Funds for the Central Universities(2015XZZX004-04)~~
文摘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.
基金supported by Collaborative Innovation Center of Suzhou Nano ScienceTechnology, MOST of China (2014CB932700)+5 种基金the National Natural Science Foundation of China (21603208, 21573206)Key Research Program of Frontier Sciences of the CAS (QYZDBSSW-SLH017)Anhui Provincial Key Scientific and Technological Project (1704a0902013)Major Program of Development Foundation of Hefei Center for Physical Science and Technology (2017FXZY002)Fundamental Research Funds for the Central UniversitiesCAS-TWAS president’s fellowship~~
文摘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.
基金the National Natural Science Foundation of China(21776215 and 21621004).
文摘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.
基金the Natural Science Foundation of Guangdong Province,China(Grant No.2016A030313339)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2017B090918002)+2 种基金the National Key Basic Research Program of China(Grant Nos.2014CB931700 and 2017YFA020623)the National Natural Science Foundation of China(Grant Nos.51832011 and 91833302)the Fund from State Key Laboratory of Optoelectronic Materials and Technologies(Grant No.OEMT2021-PZ-02)。
文摘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.
基金This work was financially supported by the National Key Research&Development Program of China(Nos.2017YFA0700104,2017YFA0403402,2017YFA0403403,and 2019YFA0405601)the National Natural Science Foundation of China(Nos.11875258,U1932213,U1932148,21773222,21872131,U1732272,U1832218,and U1932214)+4 种基金the Key Program of Research and Development of Hefei Science Center of Chinese Academy of Science(No.2017HSC-KPRD001)the Fundamental Research Funds for the Central Universities(No.WK2060000016)Collaborative Innovation Program of Hefei Science Center,Chinese Academy of Science(No.2019HSC-CIP009)Users with Excellence Program of Hefei Science Center,Chinese Academy of Science(Nos.2018HSC-UE003 and 2019HSC-UE004)the Youth Innovation Promotion Association,Chinese Academy of Science(No.2020454).
文摘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.
基金National Natural Science Foundation of China,Grant/Award Numbers:22122202,21972051。
文摘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.
基金supported by the National Natural Science Foundation of China(No.22171093)the Natural Science Foundation of Fujian Province(Nos.2022J05058 and 2022J02008)the Scientific Research Funds of Huaqiao University(No.605-50Y21048).
文摘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.
