Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical...Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical photocatalytic sites.We herein report an ion-loading pyrolysis route to in-situ anchor Pd single atoms as well as twinned Pd nanoparticles on ultra-thin graphitic carbon nitride nanosheets(PdTP/Pd_(SA)-CN)for high-efficiency photoreduction of CO_(2).The anchored Pd twinned nanoparticles donate electrons to adjacent single Pd–N_(4) sites through the carbon nitride networks,and the optimized PdTP/Pd_(SA)-CN photocatalyst exhibits a CO evolution rate up to 46.5μmol g^(-1) h^(-1) with nearly 100%selectivity.As revealed by spectroscopic and theoretical analyses,the superior photocatalytic activity is attributed to the lowered desorption barrier of carbonyl species at electron-enriched Pd single atoms,together with the improved efficiencies of light-harvesting and charge separation/transport.This work has demonstrated the engineering of the electron density of single active sites with twinned metal nanoparticles assisted by strong electronic interaction with the support of the atomic metal,and unveiled the underlying mechanism for expedited photocatalytic efficiency.展开更多
Fabrication of superior catalytic performance palladium-based catalysts with affordable cost is the key to develop direct ethanol fuel cell.Herein,Pd-decorated three-dimensional(3D)porous constructed from graphene oxi...Fabrication of superior catalytic performance palladium-based catalysts with affordable cost is the key to develop direct ethanol fuel cell.Herein,Pd-decorated three-dimensional(3D)porous constructed from graphene oxide(GO)and MXene combining with polystyrene(PS)particles as sacrificial templates(Pd/GO-MXene-PS)to elevate the catalytic performance for ethanol oxidation was proposed.The 3D porous interconnected structure of Pd/GO-MXene-PS was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM)and Brunner−Emmet−Teller(BET).By optimizing the doping ratio of MXene to GO,the mass activity of Pd/GO_(5)-MXene_(5)-PS(2944.0 mA·mg^(−1))was 3.0 times higher than that of commercial Pd/C(950.4 mA·mg^(−1))toward ethanol oxidation in base solution.Meanwhile,the rotating disk electrode(RDE)results demonstrated that Pd/GO5-MXene5-PS had a faster kinetics of ethanol oxidation.The enhanced ethanol oxidation over Pd/GO5-MXene5-PS could attribute to the excellent 3D interconnected porous structure,large surface area,good conductivity and homogeneous Pd distribution.This work provided a new idea for creating 3D porous MXene composite materials in electrocatalysis.展开更多
Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer...Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer of the photogenerated electrons from Si C to the Pd nanoparticles. As a result, the concentrated energetic electrons in the Pd nanoparticles can facilitate the cleavage of C–I or C–Br bonds, which normally requires high-temperature thermal processes. We show that the present Pd/Si C photocatalyst is capable of catalyzing the transformation of a large variety of aryl halides to their corresponding boronate esters under visible light irradiation, with excellent yields.展开更多
Size-controlled Pd nanoparticles （PdNPs） were synthesized in aqueous solution, using sodium car-boxymethyl cellulose as the stabilizer. Size-controlled PdNPs were supported onα-Al2O3 by the incipient wetness impreg...Size-controlled Pd nanoparticles （PdNPs） were synthesized in aqueous solution, using sodium car-boxymethyl cellulose as the stabilizer. Size-controlled PdNPs were supported onα-Al2O3 by the incipient wetness impregnation method. The PdNPs onα-Al2O3 support were in a narrow particle size distribution in the range of 1-6 nm. A series of PdNPs/α-Al2O3 catalysts were used for the selective hydrogenation of acetylene in ethylene-rich stream. The results show that PdNPs/α-Al2O3 catalyst with 0.03%（by mass） Pd loading is a very effective and sta-ble catalyst. With promoter Ag added, ethylene selectivity is increased from 41.0%to 63.8%at 100 ＆#176;C. Comparing with conventional Pd-Ag/α-Al2O3 catalyst, PdNPs-Ag/α-Al2O3 catalyst has better catalytic performance in acety-lene hydrogenation and shows good prospects for industrial application.展开更多
A novel electrode material based on chemically modified graphene （CMG） with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the ...A novel electrode material based on chemically modified graphene （CMG） with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the aminophenyl groups of p-phenylenediamine. Palladium nanoparticles with an average diameter of 4.2 nm are deposited on the CMG by a liquid-phase borohydride reduction. The electrocatalytic activity and stability of the Pd/CMG composite towards formic acid oxidation are found to be higher than those of reduced graphene oxide and commercial carbon materials such as Vulcan XC-72 supported Pd electrocatalysts.展开更多
Palladium nanoparticles generated in situ for Suzuki coupling reactions and aerobic alcohol oxidation in water were recovered completely using linear polystyrene. The resultant polystyrene-stabilized palladium nanopar...Palladium nanoparticles generated in situ for Suzuki coupling reactions and aerobic alcohol oxidation in water were recovered completely using linear polystyrene. The resultant polystyrene-stabilized palladium nanoparticles were shown to be reusable without any loss of activity.展开更多
Solar-driven CO_(2)conversion to prepare value-added products is highly desirable but challenging.Central to the achievement of multi-carbon products via CO_(2)photoconversion is to break the bottlenecks of C-C coupli...Solar-driven CO_(2)conversion to prepare value-added products is highly desirable but challenging.Central to the achievement of multi-carbon products via CO_(2)photoconversion is to break the bottlenecks of C-C coupling and multi-electron transfer.Herein,a charge relay system consisting of Pd-decorated BiOCl-wrapped CuBi_(2)O_(4)is reported by taking advantage of the synergy of Pd nanoparticles(PdNPs)and heterojunction for efficient CO_(2)-to-C_(2)H_(6)photoconversion.The C_(2)H_(6)production rate reached 167.1µmol g^(-1)h^(-1)with the electron selectivity of 81.1%in the absence of any sacrificial agents.The spectroscopic characterizations indicated that BiOCl nanosheets,acting as the charge relay,directionally transferred the photogenerated electrons from itself and CuBi2O4 nanorods to PdNPs for C-C coupling.The coordinated ensemble of PdNPs and heterojunction significantly elevated the charge separation and transfer efficiency.Moreover,the in-situ spectroscopic analysis supported by theoretical simulations demonstrated that the electron-rich PdNPs generated by the charge relay of PdNPs and heterojunction optimized the CO_(2)-to-C_(2)H_(6)reaction pathway and reduced the energy barrier of the key*CHOCO intermediates.This work develops an innovative strategy to design the multifunctional catalysts for the photoconversion of CO_(2)to value-added carbon products.展开更多
Hybrid materials with synergistic properties have been used for various applications.Herein,we report a green biosynthesis strategy for the fabrication of a novel Pd/bacteria@ZIF-8 composite,featuring a sandwiched str...Hybrid materials with synergistic properties have been used for various applications.Herein,we report a green biosynthesis strategy for the fabrication of a novel Pd/bacteria@ZIF-8 composite,featuring a sandwiched structure and size-selective capabilities.The Shewanella oneidensis(S.oneidensis)MR-1 was selected as the biological reductant to reduce Pd ions and synthesize Pd nanoparticles anchored on the surface of bacteria without the need for additional chemical reductants,bonding agents and toxic surfactants.This innovative sandwiched Pd/bacteria@ZIF-8 catalyst was further coated by the ZIF-8 to enhance its structural integrity.The as-prepared composite exhibits significant catalytic activity and excellent size-selective performance in the hydrogenation of olefins.This methodology opens up a horizon to designing size-selective catalysts through constructing the sandwiched structure.展开更多
The Pd-catalyzed Suzuki-Miyaura coupling reaction is a crucial tool for constructing C-C bonds.Currently,the organic solvents employed during reaction may cause serious environmental problems.Moreover,the low solubili...The Pd-catalyzed Suzuki-Miyaura coupling reaction is a crucial tool for constructing C-C bonds.Currently,the organic solvents employed during reaction may cause serious environmental problems.Moreover,the low solubility of inorganic bases in organic solvents leads to enormous mass transfer resistance.To address this issue,the Pickering droplets reactor stabilized by Pd/g-C_(3)N_(4)at substrate-water two-phase interface is reported.Benefiting from the hydrophobic conjugated framework and hydrophilic terminal groups,Pd/g-C_(3)N_(4)can configure stable Pickering emulsion without additional functionalization.The Pd loaded catalysts exhibits excellent performance(TOF=21852 h^(-1))for the Suzuki-Miyaura coupling reaction,which is deriving from unique electronic structure of g-C_(3)N_(4)and high interfacial area of emulsion.Moreover,there is no clear decrease in reactivity after six cycles(conversion>86%).In this study,the organic solvent was replaced by reaction substrate,and the high activity can be achieved for various halogenated aromatic hydrocarbons and their derivatives.展开更多
Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process.As a key unit in the fixed-bed system,catalytically active packing materials a...Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process.As a key unit in the fixed-bed system,catalytically active packing materials are required to possess some properties,such as high activity,excellent stability,and porous packing structure.Herein,we prepare a fibrous fixed-bed catalyst by anchoring Pd nanoparticles on N-doped graphene fiber(NHG)(Pd/NGF).Due to the porous and loose packing structure,the resultant Pd/NGF catalyst can be easily filled into the continuous-flow reactor to construct a fixed-bed system with low flow resistance.The corresponding catalytic fixed-bed system exhibits a favourable flow rate(8 mL/min)and excellent durability toward reduction reactions of N-containing unsaturated compounds to produce aromatic amines.This work provides a new design concept of fibrous fixed-bed catalysts with dual-active components(i.e.,graphene-derived active materials and metal nanoparticles)and catalytic organic synthesis in a continuous-flow process.展开更多
Active-phase engineering is regularly utilized to tune the selectivity of metal nanoparticles （NPs） in heterogeneous catalysis. However, the lack of understanding of the active phase in electrocatalysis has hampered...Active-phase engineering is regularly utilized to tune the selectivity of metal nanoparticles （NPs） in heterogeneous catalysis. However, the lack of understanding of the active phase in electrocatalysis has hampered the development of efficient catalysts for CO2 electroreduction. Herein, we report the systematic engineering of active phases of Pd NPs, which are exploited to select reaction pathways for CO2 electroreduction. In situ X-ray absorption spectroscopy, in situ attenuated total reflection-infrared spectroscopy, and density functional theory calculations suggest that the formation of a hydrogen-adsorbed Pd surface on a mixture of the α- and β-phases of a palladium-hydride core （α＋β PdHx@PdHx） above -0.2 V （vs. a reversible hydrogen electrode） facilitates formate production via the HCOO intermediate, whereas the formation of a metallic Pd surface on the β-phase Pd hydride core （β PdHx@Pd） below -0.5 V promotes CO production via the COOH＂ intermediate. The main product, which is either formate or CO, can be selectively produced with high Faradaic efficiencies （〉90%） and mass activities in the potential window of 0.05 to -0.9 V with scalable application demonstration.展开更多
In this work,a novel in situ auto-reduction strategy was developed to encapsulate uniformly dispersed Pd clusters/nanoparticles in MIL-125-NH_(2).It is demonstrated that the amino groups in MIL-125-NH_(2)can react wit...In this work,a novel in situ auto-reduction strategy was developed to encapsulate uniformly dispersed Pd clusters/nanoparticles in MIL-125-NH_(2).It is demonstrated that the amino groups in MIL-125-NH_(2)can react with formaldehyde to form novel reducing groups(-NH-CH_(2)OH),which can in situ auto-reduce the encapsulated Pd^(2+)ions to metallic Pd clusters/nanoparticles.As no additional reductants are required,the strategy limits the aggregation and migration of Pd clusters and the formation of large Pd nanoparticles via controlling the amount of Pd^(2+)precursor.When applied as catalysts in the hydrogenation of phenol in the aqueous phase,the obtained Pd(1.5)/MIL-125-NH-CH_(2)OH catalyst with highly dispersed Pd clusters/nanoparticles with the size of around 2 nm exhibited 100%of phenol conversion and 100%of cyclohexanone selectivity at 70℃ after 5 h,as well as remarkable reusability for at least five cycles due to the large MOF surface area,the highly dispersed Pd clusters/nanoparticles and their excellent stability within the MIL-125-NH-CH_(2)OH framework.展开更多
Product selectivity adjustment is a much-studied topic in mesoscience that is critical for industrial processes and strongly related to reaction intermediates formed by interactions between catalytic active sites and ...Product selectivity adjustment is a much-studied topic in mesoscience that is critical for industrial processes and strongly related to reaction intermediates formed by interactions between catalytic active sites and reactants.Herein,we report efficient adjustment of the product selectivity in the hydrogenation of substituted nitroarenes via rational reaction intermediates achieved using controllable Pd nanoparticles.Pd nanoparticles fixed within zeolite Beta crystals(Pd@Beta)afforded rational Pd-NO2 interactions,in which the Pd nanoparticle-adsorbed substituted nitroarenes,such as nitrobenzaldehyde,were reasonably hydrogenated into the corresponding aminobenzaldehyde.However,for Pd nanoparticles supported on the external surfaces of zeolite beta crystals,various side products were obtained owing to the coexistence of Pd-NO2 and Pd-C=O interactions.When Pd nanoparticles were artificially controlled in various positions in a fixed-bed reactor,the product selectivity was significantly affected.These results demonstrate the importance of molecular adsorption and diffusion processes in adjusting product selectivity in catalytic reactions.展开更多
Pd nanoparticles less than 8 nm were photoinduced by a near-IR femtosecond laser. The sign of the refraction nonlinearity is negative for the Pd nanoparticles with TiO2, while it is positive for those without TiO2.
An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the ...An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the modified Langmuir-Blodgett(LB)method,and the electrocatalytic oxidation of mononucleotide of guanosine 5′-monophosphate(GMP)on an ITO/TiO2-Ru electrode after Pd-photodeposition(denoted as ITO/TiO2-Ru/Pd)has been studied.Atomic force microscopy reveals that the single-layered hybrid film of TiO2 nanosheets/[Ru(phen)2(dC18bpy)] 2+is closely packed at a surface pressure of 25 mN m 1and has a thickness of(3.20±0.5)nm.X-ray photoelectron spectra show the formation of Pd nanoparticles on the surface of hybrid film with radii of 20–200 nm by the reduction of[Pd(NH3)4] 2+ under light irradiation.When it is applied to oxidize GMP,a larger catalytic oxidative current is achieved on the ITO/TiO2-Ru/Pd electrode at the external potential above 700 mV(vs.Ag|AgCl|KCl)in comparison with the naked ITO electrode and ITO/TiO2-Ru electrode.Such a result indicates that the Pd nanoparticles are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II)complexes,and thus develops the electron transfer efficiency and produces the enhanced redox current.展开更多
Ti O2-supported Pd Au bimetallic nanoparticles(NPs) with small size and good dispersity were prepared by the room-temperature ionic liquid-assisted bimetal sputtering, which is simple, environmentally friendly, and fr...Ti O2-supported Pd Au bimetallic nanoparticles(NPs) with small size and good dispersity were prepared by the room-temperature ionic liquid-assisted bimetal sputtering, which is simple, environmentally friendly, and free of additives and byproducts. Pd/Au atomic ratio can be tuned by controlling the sputtering conditions simply. High catalytic activity was found in Pd Au–NPs–Ti O2 hybrids for solvent-free selective oxidation of 1-phenylethanol using O2 as the oxidant at the low temperature of 50 °C and low pressure of 1 atm. It was found that Pd/Au ratio strongly affected the catalytical activity, and the highest conversion of about 35 % and turnover frequency of about 421 h-1were achieved at 1:1 of Pd/Au atomic ratio. The synergistic effect in Pd Au NPs was also discussed based on the comprehensive characterization results.The present approach may offer an alternative platform for future development of green-chemistry compatible bimetallic nanocatalysts.展开更多
Lipid microtubules with wound ribbon features were fabricated by self-assembling method, and the deposition patterns of colloidal Pd particles on tubular template were investigated. The result indicates that colloidal...Lipid microtubules with wound ribbon features were fabricated by self-assembling method, and the deposition patterns of colloidal Pd particles on tubular template were investigated. The result indicates that colloidal Pd nanoparticles are preferentially decorated on the helical markings in the interior and on the exterior of preformed tubule and to the edge of loosely helical ribbons to obtain helical deposition features. The multi-bilayer microstruc-ture of tubules can be marked by fine Pd nanoparticles deposited at the edge of helical ribbon. There are the site-specific interactions between lipid tubular template and colloidal Pd particles at the helical edge. A new route was illustrated that colloidal Pd particles firstly attach at the edge of thin flat membranes, and then thin membranes roll up and reassemble into tubule together with particles to form helical deposition patterns. The site-specific depo-sition of Pd is unbeneficial to obtain the homogeneous metal film on tubules, but it can be utilized to reveal the dif-ferent chemical nature of lipid molecular assembly.展开更多
Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobili...Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy（SEM） and Transmission Electron Microscopy（TEM）. The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid（DCAA） dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.展开更多
Pd-Rh nanoparticles are known to easily undergo surface restructuring in reactive environment. This study quantifies, with the help of density functional(DFT) calculations and a novel topological approach, atomic orde...Pd-Rh nanoparticles are known to easily undergo surface restructuring in reactive environment. This study quantifies, with the help of density functional(DFT) calculations and a novel topological approach, atomic ordering and surface segregation effects in Pd-Rh particles with compositions 1:3, 1:1 and 3:1 containing up to 201 atoms(ca. 1.7 nm). The obtained data are used to reliably optimise energetically preferred atomic orderings in inaccessible by DFT Pd-Rh particles containing thousands of atoms and exhibiting sizes exceeding 5 nm, which are typical for catalytic metal particles. It is outlined, how segregation effects on the surface arrangement of Pd-Rh nanoalloy catalysts induced by adsorbates can be evaluated in a simple way within the present modelling setup.展开更多
Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary...Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary heterojunction Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)nanocomposites were facilely prepared for the first time by a two-step method.The visible-light-promoted hydrogen production rate of 0.3%Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)reaches up to 5.26 mmol g^(-1)h^(-1),which is evidently much higher than pure UiO-66-NH_(2),ZnIn_(2)S_(4)and binary UiO-66-NH_(2)/ZnIn_(2)S_(4)composites.Such a huge improvement in the photocatalytic performance is mainly attributed to the matched band gap of ZnIn_(2)S_(4)and UiO-66-NH_(2),and the introduction of Pd NPs into photocatalysts that broaden spectral response range and promote the photon induced charge carrier separation.This work may provide a feasible approach for the design and construction of metal-organic-frameworks-based photocatalytic materials.展开更多
基金We appreciate the financial support from the National Natural Science Foundation of China(22272150,22102145)the Major Program of Zhejiang Provincial Natural Science Foundation(LD22B030002)+3 种基金Zhejiang Provincial Ten Thousand Talent Program(2021R51009)Zhejiang Provincial Natural Science Foundation of China(LQ23B030006,LY22B030012)Shandong Provincial Natural Science Foundation of China(2020MB053)the Fundamental Research Funds for the Central Universities(DUT22RC(3)084).
文摘Modulating electronic structures of single-atom metal cocatalysts is vital for highly active photoreduction of CO_(2),and it's especially challenging to develop a facile method to modify the dispersion of atomical photocatalytic sites.We herein report an ion-loading pyrolysis route to in-situ anchor Pd single atoms as well as twinned Pd nanoparticles on ultra-thin graphitic carbon nitride nanosheets(PdTP/Pd_(SA)-CN)for high-efficiency photoreduction of CO_(2).The anchored Pd twinned nanoparticles donate electrons to adjacent single Pd–N_(4) sites through the carbon nitride networks,and the optimized PdTP/Pd_(SA)-CN photocatalyst exhibits a CO evolution rate up to 46.5μmol g^(-1) h^(-1) with nearly 100%selectivity.As revealed by spectroscopic and theoretical analyses,the superior photocatalytic activity is attributed to the lowered desorption barrier of carbonyl species at electron-enriched Pd single atoms,together with the improved efficiencies of light-harvesting and charge separation/transport.This work has demonstrated the engineering of the electron density of single active sites with twinned metal nanoparticles assisted by strong electronic interaction with the support of the atomic metal,and unveiled the underlying mechanism for expedited photocatalytic efficiency.
基金financially supported by the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(No.A30B191410)the Sailing Project from Science and Technology Commission of Shanghai Municipality(No.17YF1406600)+6 种基金Chenguang Project Supported by Shanghai Municipal Education Commission(No.18CG68)Gaoyuan Discipline of Shanghai-Materials Science and Engineering(No.A30NH221903)the Open Project of Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices(Soochow University)(No.KS2022)Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 ProjectJoint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe Project of Guangdong Provincial Education(No.2020KTSCX131)。
文摘Fabrication of superior catalytic performance palladium-based catalysts with affordable cost is the key to develop direct ethanol fuel cell.Herein,Pd-decorated three-dimensional(3D)porous constructed from graphene oxide(GO)and MXene combining with polystyrene(PS)particles as sacrificial templates(Pd/GO-MXene-PS)to elevate the catalytic performance for ethanol oxidation was proposed.The 3D porous interconnected structure of Pd/GO-MXene-PS was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM)and Brunner−Emmet−Teller(BET).By optimizing the doping ratio of MXene to GO,the mass activity of Pd/GO_(5)-MXene_(5)-PS(2944.0 mA·mg^(−1))was 3.0 times higher than that of commercial Pd/C(950.4 mA·mg^(−1))toward ethanol oxidation in base solution.Meanwhile,the rotating disk electrode(RDE)results demonstrated that Pd/GO5-MXene5-PS had a faster kinetics of ethanol oxidation.The enhanced ethanol oxidation over Pd/GO5-MXene5-PS could attribute to the excellent 3D interconnected porous structure,large surface area,good conductivity and homogeneous Pd distribution.This work provided a new idea for creating 3D porous MXene composite materials in electrocatalysis.
基金supported by the National Natural Science Foudation of China(21473232,21673271,U1710112)
文摘Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer of the photogenerated electrons from Si C to the Pd nanoparticles. As a result, the concentrated energetic electrons in the Pd nanoparticles can facilitate the cleavage of C–I or C–Br bonds, which normally requires high-temperature thermal processes. We show that the present Pd/Si C photocatalyst is capable of catalyzing the transformation of a large variety of aryl halides to their corresponding boronate esters under visible light irradiation, with excellent yields.
基金Supported by SINOPEC Beijing Research Institute of Chemical Industry(01-09ZS0440,11-08ZS0442)
文摘Size-controlled Pd nanoparticles （PdNPs） were synthesized in aqueous solution, using sodium car-boxymethyl cellulose as the stabilizer. Size-controlled PdNPs were supported onα-Al2O3 by the incipient wetness impregnation method. The PdNPs onα-Al2O3 support were in a narrow particle size distribution in the range of 1-6 nm. A series of PdNPs/α-Al2O3 catalysts were used for the selective hydrogenation of acetylene in ethylene-rich stream. The results show that PdNPs/α-Al2O3 catalyst with 0.03%（by mass） Pd loading is a very effective and sta-ble catalyst. With promoter Ag added, ethylene selectivity is increased from 41.0%to 63.8%at 100 ＆#176;C. Comparing with conventional Pd-Ag/α-Al2O3 catalyst, PdNPs-Ag/α-Al2O3 catalyst has better catalytic performance in acety-lene hydrogenation and shows good prospects for industrial application.
基金supported by the National Basic Research Program of China(Grant No.2007CB209700)the Graduate Student Innovation Foundation of Jiangsu Province,China(Grant No.CX09B_075Z)the Research Funding of Nanjing University of Aeronautics and Astronautics,China(Grant No.NS2010165)
文摘A novel electrode material based on chemically modified graphene （CMG） with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the aminophenyl groups of p-phenylenediamine. Palladium nanoparticles with an average diameter of 4.2 nm are deposited on the CMG by a liquid-phase borohydride reduction. The electrocatalytic activity and stability of the Pd/CMG composite towards formic acid oxidation are found to be higher than those of reduced graphene oxide and commercial carbon materials such as Vulcan XC-72 supported Pd electrocatalysts.
基金the Nanomaterials and Micro-devices Research Center(NMRC)of OIT for financial and instrumental supportssupported by the Joint Studies Program(2010)of the Institute for Mo-lecular Science.
文摘Palladium nanoparticles generated in situ for Suzuki coupling reactions and aerobic alcohol oxidation in water were recovered completely using linear polystyrene. The resultant polystyrene-stabilized palladium nanoparticles were shown to be reusable without any loss of activity.
基金supported by the National Natural Science Foundation of China(22302002,22375006)the University Science Research Project of Anhui Province(2022AH050182,2022AH020020)。
文摘Solar-driven CO_(2)conversion to prepare value-added products is highly desirable but challenging.Central to the achievement of multi-carbon products via CO_(2)photoconversion is to break the bottlenecks of C-C coupling and multi-electron transfer.Herein,a charge relay system consisting of Pd-decorated BiOCl-wrapped CuBi_(2)O_(4)is reported by taking advantage of the synergy of Pd nanoparticles(PdNPs)and heterojunction for efficient CO_(2)-to-C_(2)H_(6)photoconversion.The C_(2)H_(6)production rate reached 167.1µmol g^(-1)h^(-1)with the electron selectivity of 81.1%in the absence of any sacrificial agents.The spectroscopic characterizations indicated that BiOCl nanosheets,acting as the charge relay,directionally transferred the photogenerated electrons from itself and CuBi2O4 nanorods to PdNPs for C-C coupling.The coordinated ensemble of PdNPs and heterojunction significantly elevated the charge separation and transfer efficiency.Moreover,the in-situ spectroscopic analysis supported by theoretical simulations demonstrated that the electron-rich PdNPs generated by the charge relay of PdNPs and heterojunction optimized the CO_(2)-to-C_(2)H_(6)reaction pathway and reduced the energy barrier of the key*CHOCO intermediates.This work develops an innovative strategy to design the multifunctional catalysts for the photoconversion of CO_(2)to value-added carbon products.
基金supported by the Young Talent Support Fund from Jiangsu University(No.5501310013)Jiangsu Provincial Founds for Young Scholars(Nos.BK20210782 and BK20210744)+2 种基金the Fellowship of China Postdoctoral Science Foundation(No.2022M720057)Wenzhou Science&Technology Program(No.ZG2021025)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515111017).
文摘Hybrid materials with synergistic properties have been used for various applications.Herein,we report a green biosynthesis strategy for the fabrication of a novel Pd/bacteria@ZIF-8 composite,featuring a sandwiched structure and size-selective capabilities.The Shewanella oneidensis(S.oneidensis)MR-1 was selected as the biological reductant to reduce Pd ions and synthesize Pd nanoparticles anchored on the surface of bacteria without the need for additional chemical reductants,bonding agents and toxic surfactants.This innovative sandwiched Pd/bacteria@ZIF-8 catalyst was further coated by the ZIF-8 to enhance its structural integrity.The as-prepared composite exhibits significant catalytic activity and excellent size-selective performance in the hydrogenation of olefins.This methodology opens up a horizon to designing size-selective catalysts through constructing the sandwiched structure.
基金the National Natural Science Foundation of China(22178243).
文摘The Pd-catalyzed Suzuki-Miyaura coupling reaction is a crucial tool for constructing C-C bonds.Currently,the organic solvents employed during reaction may cause serious environmental problems.Moreover,the low solubility of inorganic bases in organic solvents leads to enormous mass transfer resistance.To address this issue,the Pickering droplets reactor stabilized by Pd/g-C_(3)N_(4)at substrate-water two-phase interface is reported.Benefiting from the hydrophobic conjugated framework and hydrophilic terminal groups,Pd/g-C_(3)N_(4)can configure stable Pickering emulsion without additional functionalization.The Pd loaded catalysts exhibits excellent performance(TOF=21852 h^(-1))for the Suzuki-Miyaura coupling reaction,which is deriving from unique electronic structure of g-C_(3)N_(4)and high interfacial area of emulsion.Moreover,there is no clear decrease in reactivity after six cycles(conversion>86%).In this study,the organic solvent was replaced by reaction substrate,and the high activity can be achieved for various halogenated aromatic hydrocarbons and their derivatives.
基金the Key Research and Development Program of Hubei Province(No.2022BAA026)the Open/Innovation Project of Key Laboratory of Novel Biomass-Based Environmental and Energy Materials in Petroleum and Chemical Industry(No.2022BEEA06)+3 种基金the Open Project of Hubei Key Laboratory of Novel Reactor and Green Chemical Technology(No.NRGC202203)the Open Project of Key Laboratory of Green Chemical Engineering Process of Ministry of Education(No.GCP20220205)the Innovation and Entrepreneurship Training Program Funded by Wuhan Institute of Technology(No.202310490007)the Postgraduate Innovation Foundation from Wuhan Institute of Technology(No.CX2022459).
文摘Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process.As a key unit in the fixed-bed system,catalytically active packing materials are required to possess some properties,such as high activity,excellent stability,and porous packing structure.Herein,we prepare a fibrous fixed-bed catalyst by anchoring Pd nanoparticles on N-doped graphene fiber(NHG)(Pd/NGF).Due to the porous and loose packing structure,the resultant Pd/NGF catalyst can be easily filled into the continuous-flow reactor to construct a fixed-bed system with low flow resistance.The corresponding catalytic fixed-bed system exhibits a favourable flow rate(8 mL/min)and excellent durability toward reduction reactions of N-containing unsaturated compounds to produce aromatic amines.This work provides a new design concept of fibrous fixed-bed catalysts with dual-active components(i.e.,graphene-derived active materials and metal nanoparticles)and catalytic organic synthesis in a continuous-flow process.
文摘Active-phase engineering is regularly utilized to tune the selectivity of metal nanoparticles （NPs） in heterogeneous catalysis. However, the lack of understanding of the active phase in electrocatalysis has hampered the development of efficient catalysts for CO2 electroreduction. Herein, we report the systematic engineering of active phases of Pd NPs, which are exploited to select reaction pathways for CO2 electroreduction. In situ X-ray absorption spectroscopy, in situ attenuated total reflection-infrared spectroscopy, and density functional theory calculations suggest that the formation of a hydrogen-adsorbed Pd surface on a mixture of the α- and β-phases of a palladium-hydride core （α＋β PdHx@PdHx） above -0.2 V （vs. a reversible hydrogen electrode） facilitates formate production via the HCOO intermediate, whereas the formation of a metallic Pd surface on the β-phase Pd hydride core （β PdHx@Pd） below -0.5 V promotes CO production via the COOH＂ intermediate. The main product, which is either formate or CO, can be selectively produced with high Faradaic efficiencies （〉90%） and mass activities in the potential window of 0.05 to -0.9 V with scalable application demonstration.
基金financial support from the National Natural Science Foundation of China(Grant No.51802015)the Research Department Closed Carbon Cycle Economy(CCCE)at the Ruhr-University Bochum,Fundamental Research Funds for the Central Universities(No.FRF-TP-20-005A3)the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange&Growth Program(Grant No.QNXM20210016)。
文摘In this work,a novel in situ auto-reduction strategy was developed to encapsulate uniformly dispersed Pd clusters/nanoparticles in MIL-125-NH_(2).It is demonstrated that the amino groups in MIL-125-NH_(2)can react with formaldehyde to form novel reducing groups(-NH-CH_(2)OH),which can in situ auto-reduce the encapsulated Pd^(2+)ions to metallic Pd clusters/nanoparticles.As no additional reductants are required,the strategy limits the aggregation and migration of Pd clusters and the formation of large Pd nanoparticles via controlling the amount of Pd^(2+)precursor.When applied as catalysts in the hydrogenation of phenol in the aqueous phase,the obtained Pd(1.5)/MIL-125-NH-CH_(2)OH catalyst with highly dispersed Pd clusters/nanoparticles with the size of around 2 nm exhibited 100%of phenol conversion and 100%of cyclohexanone selectivity at 70℃ after 5 h,as well as remarkable reusability for at least five cycles due to the large MOF surface area,the highly dispersed Pd clusters/nanoparticles and their excellent stability within the MIL-125-NH-CH_(2)OH framework.
基金This work is supported by the National Natural Science Foundation of China(91634201,21403192 and 91645105)the China Postdoctoral Science Foundation(2018M630662)。
文摘Product selectivity adjustment is a much-studied topic in mesoscience that is critical for industrial processes and strongly related to reaction intermediates formed by interactions between catalytic active sites and reactants.Herein,we report efficient adjustment of the product selectivity in the hydrogenation of substituted nitroarenes via rational reaction intermediates achieved using controllable Pd nanoparticles.Pd nanoparticles fixed within zeolite Beta crystals(Pd@Beta)afforded rational Pd-NO2 interactions,in which the Pd nanoparticle-adsorbed substituted nitroarenes,such as nitrobenzaldehyde,were reasonably hydrogenated into the corresponding aminobenzaldehyde.However,for Pd nanoparticles supported on the external surfaces of zeolite beta crystals,various side products were obtained owing to the coexistence of Pd-NO2 and Pd-C=O interactions.When Pd nanoparticles were artificially controlled in various positions in a fixed-bed reactor,the product selectivity was significantly affected.These results demonstrate the importance of molecular adsorption and diffusion processes in adjusting product selectivity in catalytic reactions.
文摘Pd nanoparticles less than 8 nm were photoinduced by a near-IR femtosecond laser. The sign of the refraction nonlinearity is negative for the Pd nanoparticles with TiO2, while it is positive for those without TiO2.
基金supported by the National Natural Science Foundation of China(21073133,20843007,20471043)Zhejiang Provincial Natural Science Foundation of China(Y5100283,Y4090248,Y4080177)Wenzhou University Foundation(2007L019)
文摘An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the modified Langmuir-Blodgett(LB)method,and the electrocatalytic oxidation of mononucleotide of guanosine 5′-monophosphate(GMP)on an ITO/TiO2-Ru electrode after Pd-photodeposition(denoted as ITO/TiO2-Ru/Pd)has been studied.Atomic force microscopy reveals that the single-layered hybrid film of TiO2 nanosheets/[Ru(phen)2(dC18bpy)] 2+is closely packed at a surface pressure of 25 mN m 1and has a thickness of(3.20±0.5)nm.X-ray photoelectron spectra show the formation of Pd nanoparticles on the surface of hybrid film with radii of 20–200 nm by the reduction of[Pd(NH3)4] 2+ under light irradiation.When it is applied to oxidize GMP,a larger catalytic oxidative current is achieved on the ITO/TiO2-Ru/Pd electrode at the external potential above 700 mV(vs.Ag|AgCl|KCl)in comparison with the naked ITO electrode and ITO/TiO2-Ru electrode.Such a result indicates that the Pd nanoparticles are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II)complexes,and thus develops the electron transfer efficiency and produces the enhanced redox current.
基金supported by the National Natural Science Foundation of China(No.61274019)the Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Ti O2-supported Pd Au bimetallic nanoparticles(NPs) with small size and good dispersity were prepared by the room-temperature ionic liquid-assisted bimetal sputtering, which is simple, environmentally friendly, and free of additives and byproducts. Pd/Au atomic ratio can be tuned by controlling the sputtering conditions simply. High catalytic activity was found in Pd Au–NPs–Ti O2 hybrids for solvent-free selective oxidation of 1-phenylethanol using O2 as the oxidant at the low temperature of 50 °C and low pressure of 1 atm. It was found that Pd/Au ratio strongly affected the catalytical activity, and the highest conversion of about 35 % and turnover frequency of about 421 h-1were achieved at 1:1 of Pd/Au atomic ratio. The synergistic effect in Pd Au NPs was also discussed based on the comprehensive characterization results.The present approach may offer an alternative platform for future development of green-chemistry compatible bimetallic nanocatalysts.
文摘Lipid microtubules with wound ribbon features were fabricated by self-assembling method, and the deposition patterns of colloidal Pd particles on tubular template were investigated. The result indicates that colloidal Pd nanoparticles are preferentially decorated on the helical markings in the interior and on the exterior of preformed tubule and to the edge of loosely helical ribbons to obtain helical deposition features. The multi-bilayer microstruc-ture of tubules can be marked by fine Pd nanoparticles deposited at the edge of helical ribbon. There are the site-specific interactions between lipid tubular template and colloidal Pd particles at the helical edge. A new route was illustrated that colloidal Pd particles firstly attach at the edge of thin flat membranes, and then thin membranes roll up and reassemble into tubule together with particles to form helical deposition patterns. The site-specific depo-sition of Pd is unbeneficial to obtain the homogeneous metal film on tubules, but it can be utilized to reveal the dif-ferent chemical nature of lipid molecular assembly.
基金supported by the Nature Science Foundation of Heilongjiang Province (No. B201410)the Postdoctoral Foundation Project of Heilongjiang Province (No. LBH-Z13128)+3 种基金the Science and Technology Research Program of Education Bureau of Heilongjiang Province (No. 12531206)the Special Scientific Research Projects of Harbin Normal University (12XQXG02)the National Nature Science Foundation of China (No. 41030743)the National Nature Science Foundation of China (No. 42171217)
文摘Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy（SEM） and Transmission Electron Microscopy（TEM）. The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid（DCAA） dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.
基金financed by the Generalitat de Catalunya via a pre-doctoral grant 2018FI-B-00384the Operational program“Science and Education for Smart Growth”,project BG05M2OP001-2.009-0028 for funding his research stay in the University of Barcelona+2 种基金financial support by the Bulgarian Ministry of Education and Science under the National Research Programme“Low-carbon Energy for the Transportsupport by the Spanish grants PGC2018-093863-B-C22,CTQ2015-64618-RMDM-2017-0767 as well as by the grant 2017SGR13 of the Generalitat de Catalunya
文摘Pd-Rh nanoparticles are known to easily undergo surface restructuring in reactive environment. This study quantifies, with the help of density functional(DFT) calculations and a novel topological approach, atomic ordering and surface segregation effects in Pd-Rh particles with compositions 1:3, 1:1 and 3:1 containing up to 201 atoms(ca. 1.7 nm). The obtained data are used to reliably optimise energetically preferred atomic orderings in inaccessible by DFT Pd-Rh particles containing thousands of atoms and exhibiting sizes exceeding 5 nm, which are typical for catalytic metal particles. It is outlined, how segregation effects on the surface arrangement of Pd-Rh nanoalloy catalysts induced by adsorbates can be evaluated in a simple way within the present modelling setup.
基金the Natural Science Foundation of Shanghai(No.19ZR1403500)the National Natural Science Foundation of China(No.21373054)the Natural Science Foundation of Shanghai Science and Technology Committee(No.19DZ2270100)。
文摘Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary heterojunction Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)nanocomposites were facilely prepared for the first time by a two-step method.The visible-light-promoted hydrogen production rate of 0.3%Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)reaches up to 5.26 mmol g^(-1)h^(-1),which is evidently much higher than pure UiO-66-NH_(2),ZnIn_(2)S_(4)and binary UiO-66-NH_(2)/ZnIn_(2)S_(4)composites.Such a huge improvement in the photocatalytic performance is mainly attributed to the matched band gap of ZnIn_(2)S_(4)and UiO-66-NH_(2),and the introduction of Pd NPs into photocatalysts that broaden spectral response range and promote the photon induced charge carrier separation.This work may provide a feasible approach for the design and construction of metal-organic-frameworks-based photocatalytic materials.
