Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimet...Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimetallic PdCu/TiO_(x)composite catalysts were synthesized with varying Pd and Cu ratios through electrochemical deposition on defective TiOxnanotube arrays.Denitrification experiments demonstrated that the Pd_(1)Cu_(1)/TiO_(x)catalyst exhibited the highest(NO_(3^(–)))removal rate(81.2%)and N_(2)selectivity(67.2%)among all tested catalysts.Leveraging the exceptional light-responsive property of TiO_(x),the introduction of light energy as an assisting factor in electrocatalysis further augmented the(NO_(3^(–)))treatment rate,resulting in a higher(NO_(3^(–)))removal rate of 95.1%and N_(2)selectivity of approximately 90%.Compared to individual electrocatalysis and photocatalysis systems,the overpotential for the catalytic interface active*H formation in the photo-assisted electrocatalysis system was remarkably reduced,thus accelerating electron migration and promoting(NO_(3^(–)))reduction kinetics.Economic analysis revealed an energy consumption of 2.74 k Wh/mol and a corresponding energy consumption per order(EEO)of 0.79 k Wh/m^(3)for the Pd_(1)Cu_(1)/TiOxcatalyst to reduce 25.2 mg/L of(NO_(3^(–)))-N in water to N_(2),showcasing remarkable competitiveness and economic advantages over other water treatment technologies.This study developed the PdCu/TiOxelectrocatalysts with high(NO_(3^(–)))removal rates and N_(2)selectivity,particularly when combined with light energy,the efficiency and selectivity were significantly enhanced,offering a competitive and economically viable solution for wastewater treatment.展开更多
Replacing the energy‐intensive Haber–Bosch process with electrocatalytic urea synthesis from waste NO_(3)−and CO_(2) is hindered by kinetic competition from undesirable^(*)NOH‐mediated NH_(3) formation.Herein,we de...Replacing the energy‐intensive Haber–Bosch process with electrocatalytic urea synthesis from waste NO_(3)−and CO_(2) is hindered by kinetic competition from undesirable^(*)NOH‐mediated NH_(3) formation.Herein,we design a spin‐polarized PdCu/TiO_(2)‐x catalyst with oxygen vacancies(OV)to enable regioselective C‐N coupling.The OV engineering synergistically modulates NO adsorption configurations and suppresses oxygen‐terminal hydrogenation(NO→^(*)NOH),redirecting the pathway toward^(*)NO→^(*)HNO for urea formation.This dynamic control achieves a record urea yield of 37.84 mmol h^(−1) g^(−1) at low voltage,outperforming most reported catalysts.Operando attenuated total reflection–surface‐enhanced infrared absorption spectroscopy(ATR‐SEIRAS)and density functional theory(DFT)studies confirm that OV enhance NO_(3)−/CO_(2) co‐adsorption,accelerate the rate‐determining NO→HNO step,and stabilize dispersed PdCu clusters for increased active sites.This spin‐defect synergy offers a sustainable strategy for electro‐synthesizing urea while valorizing environmental pollutants.展开更多
如何构筑高性能的电催化剂是提高卤代有机污染物电催化还原去除的关键.本研究通过化学共还原的方法制备出钯铜(PdCu)纳米合金催化剂,通过扫描电子显微镜(SEM)、高分辨率透射电子显微镜(HRTEM)、能量色散X射线光谱(EDX)、X射线衍射(XRD)...如何构筑高性能的电催化剂是提高卤代有机污染物电催化还原去除的关键.本研究通过化学共还原的方法制备出钯铜(PdCu)纳米合金催化剂,通过扫描电子显微镜(SEM)、高分辨率透射电子显微镜(HRTEM)、能量色散X射线光谱(EDX)、X射线衍射(XRD)、X射线光电子能谱(XPS)、线性扫描伏安法(LSV)和电化学阻抗谱(EIS)等方法对其微观结构和电化学性能进行表征,并探究PdCu纳米合金催化剂对抗生素氟苯尼考(Florfenicol,FLO)电催化还原的降解机理.实验结果表明,所制备的PdCu纳米合金催化剂中Pd、Cu纳米颗粒分布均匀,具有优异的电化学还原性能和动力学性能以及快速的电子转移速率.PdCu纳米合金催化剂在-1.3 V vs.Hg/Hg_(2)SO_(4)下,120 min内对FLO的去除率高达97.5%,远高于纯Pd(82.9%)、纯Cu(67.4%)金属纳米颗粒催化剂的去除率,中性pH更有利于FLO的降解.叔丁醇淬灭实验表明,吸附态原子氢在电催化还原去除FLO过程中起重要作用.使用液质联用仪(LC-MS/MS)对FLO降解后的产物进行半定量分析表明,在PdCu纳米合金催化剂上FLO的电催化还原是一个逐步脱卤的过程,在实现完全脱氯后再进行脱氟.本研究为电催化高效还原卤代有机污染物提供了一种具有应用潜力的催化剂方案.展开更多
Developing efficient and stable bimetallic Pdbased anode electrocatalysts toward formic acid oxidation(FAO)is of great significance for commercial applications of direct formic acid fuel cells(DFAFCs).Herein,we report...Developing efficient and stable bimetallic Pdbased anode electrocatalysts toward formic acid oxidation(FAO)is of great significance for commercial applications of direct formic acid fuel cells(DFAFCs).Herein,we report a facile synthesis approach to fabricate PdCu nanoclusters(NCs)catalysts with granular-film structure.The introduction of Cu can adjust the electronic structure and d-band center of Pd,which can improve the catalytic performance of the catalysts.Compared with Pd NCs catalyst,the catalytic durability and activity of PdCu NCs catalysts for FAO are greatly improved.The order for catalytic activity of NC metals is Pd_(85)Cu_(15)NCs>Pd_(70)Cu_(30)NCs>Pd NCs.The maximum mass activity can be acquired with the Pd_(85)Cu_(15)NCs catalyst,which is about1.7 times that of the Pd NCs catalyst.And Pd_(85)Cu_(15)NCs catalyst still maintains the highest catalytic current density after 50 cycles,indicating that Pd_(85)Cu_(15)NCs catalyst has the best durability and electrocatalytic activity for FAO.Our work provides a new prospect for the design of highly efficient anode catalysts materials for DFAFCs.展开更多
The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is res...The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is responsible for the adsorption and activation of CO_(2)and the generation of CO and H2via side reactions often lead to poor efficiency and low selectivity of the catalyst.Herein,Cu,Pd,and PdCu metal clusters cocatalyst-anchored defective TiO_(2)nanotubes(Cu/TiO_(2)-SBO,Pd/TiO_(2)-SBO,and Pd1Cu1/TiO_(2)-SBO)were designed via a simple solution impregnation reduction and applied for photocatalytic conversion of CO_(2)to CH_(4).The Pd1Cu1/TiO_(2)-SBO photocatalyst exhibits excellent catalytic performance among the other catalysts for photoreduction of CO_(2)into CH_(4).More interestingly,the product selectivity of CH_(4)reaches up to 100%with a rate of 25μmol g^(-1)h^(-1).In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)simulations indicate that the main reasons for the high selectivity of CH_(4)are attributed to the PdCu alloy and oxygen vacancies,which jointly enhance the photoinduced carrier separation and lower energy barriers of key intermediates.Moreover,due to the tunable d-band center of the Cu site in the PdCu alloy,the generated intermediates can be well prevented from poisoning and promoted to participate in further reactions.Hopefully,the current study will provide insight into the development of new,highly selective photocatalysts for the visible light-catalytic reduction of CO_(2)into CH_(4).展开更多
Transport of charge carriers in percolating nanocluster devices based on bimetallic PdCu nanoclusters was investigated in this work. The device was fabricated by self-assembly of the nanoclusters between electrical el...Transport of charge carriers in percolating nanocluster devices based on bimetallic PdCu nanoclusters was investigated in this work. The device was fabricated by self-assembly of the nanoclusters between electrical electrodes inside an ultra-high vacuum compatible system. The average size of the produced nanoclusters was 7.3 nm, and the composition was Pdo.77Cuo.23. Systematic in situ current-voltage measurements as a function of temperature were per- formed which provide a conductance-temperature profile. The results are explained in terms of the charge carriers＇ tunneling through small potential barriers at the junctions between nanoclusters. The results predict the size of the nanoclusters as well as the magnitude of the potential difference of the tunneling barriers. This investigation helps understanding the nature of the interface between the nanoclusters and the charge carrier transport within those devices to be utilized for optimizing gas sensing properties of PdCu nanocluster devices.展开更多
Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have simila...Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.展开更多
Electrocatalysis,a form of heterogeneous catalysis,is closely associated with both catalyst properties and the catalyst/electrolyte interfacial microenvironment.Herein,we rationally design and synthesize a unique PdCu...Electrocatalysis,a form of heterogeneous catalysis,is closely associated with both catalyst properties and the catalyst/electrolyte interfacial microenvironment.Herein,we rationally design and synthesize a unique PdCu nano-sea urchins(PdCu NSUs)featured with high-curvature nanotips,by which the interfacial microenvironment is expected to be tailored to the electrocatalytic reactions.PdCu NSUs exhibit excellent activity for ethanol electrooxidation,with a specific activity of 4.11 mA cm^(-2)and a mass activity of 2.24 mAμg_(Pd)^(-1),and a high Faraday efficiency(FE)of 96.4%toward acetic acid.COMSOL finite element simulations confirm that the unique nanotips could induce a local electric field due to the accumulation of positive charges in the nanotips,resulting in enrichment of OH^(-)at the catalyst surface to promote the formation of Pd-OH_(ads),a species required by ethanol dehydrogenation.Furthermore,DFT calculations and in-situ electrochemical Fourier transform infrared spectroscopy discover that the d-band center of Pd significantly downshifts in PdCu alloy,which facilitates the desorption of the produced acetic acid.This work provides a new electrocata lytic material with high-curvature nanotips,and also clarifies how the material morphology,by inducing local electric fields,affects the interfacial microenvironment and thus the catalytic activity and selectivity.展开更多
Suzuki-Miyaura reactions, involving the activation of carbon-halogen bonds, especially C-C1 bonds, have drawn widespread attention because of their huge industrial potential. However, these reactions are dependent on ...Suzuki-Miyaura reactions, involving the activation of carbon-halogen bonds, especially C-C1 bonds, have drawn widespread attention because of their huge industrial potential. However, these reactions are dependent on the development of highly active and stable catalysts. Herein, we developed a convenient one-pot wet route to synthesize PdxCuy bimetallic nanocrystals for the Suzuki-Miyaura reaction. By introducing Cu, an earth-abundant element, the catalytic activity was greatly enhanced while the amount of Pd required was reduced. PdxCuy nanocrystals of different compositions, including PdBCu, Pd2Cu, PdCu, PdCu2, and PdCu3, were successfully synthesized by tuning the Pd：Cu ratio. Their catalytic performance in Suzuki-Miyaura reactions between phenylboronic acid and halobenzenes （iodo-, bromo-, or chlorobenzene） showed that PdCua nanocatalyst demonstrated the best efficacy.展开更多
The design of high-performance catalysts is the key to the efficient utilization of hydrogen energy.In this work,a PdCu nanoalloy was successfully anchored on TiO_(2)encapsulated with carbon to construct a catalyst.Ou...The design of high-performance catalysts is the key to the efficient utilization of hydrogen energy.In this work,a PdCu nanoalloy was successfully anchored on TiO_(2)encapsulated with carbon to construct a catalyst.Outstanding kinetics of the hydrolysis of ammonia borane(turnover frequency of 279 mol·min^(-1·)mol_(Pd)^(-1))ranking the third place among Pd-based catalysts was achieved in the absence of alkali.Both experimental research and theoretical calculations reveal a lower activation energy of the B-H bond on the PdCu nanoalloy catalyst than that on pristine Pd and a lower activation energy of the O-H bond than that on pristine Cu.The redistribution of d electron and the shift of the d-band center play a critical role in increasing the electron density of Pd and improving the catalytic performances of Pd_(0.1)Cu_(0.9)/TiO_(2)-porous carbon(Pd_(0.1)Cu_(0.9)/T-PC).This work provides novel insights into highly dual-active alloys and sheds light on the mechanism of dual-active sites in promoting borohydride hydrolysis.展开更多
The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly ...The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly dependent on the activity and stable of catalysts.Herein,the support morphology-dependent catalytic performance of SMC reactions was investigated.The truncated hexagonal bipyramid(α-Fe_(2)O_(3)-O)and rod-shaped morphologies of alpha-Fe_(2)O_(3)(α-Fe_(2)O_(3)-R)were used as support to prepare PdCu nanoparticles(NPs)catalysts by NaBH_(4) reduction method.For PdCu/α-Fe_(2)O_(3)-R catalysts,the smaller size of PdCu NPs and more low coordination Pd sites leading to its superior catalytic performance for SMC reactions.Furthermore,it can be easily recycled through centrifugation and reused several times without obvious loss on its catalytic performance.Identical location transmission electron microscopy method was used to investigate the structural evolution of PdCu/α-Fe_(2)O_(3)-R catalysts.The results found that its structure almost unchanged during the catalytic reaction.展开更多
基金the National Natural Science Foundation of China(No.52300084)China Postdoctoral Science Foundation(No.2023M741151)the Fundamental Research Funds for the Central Universities(No.2024MS063)。
文摘Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimetallic PdCu/TiO_(x)composite catalysts were synthesized with varying Pd and Cu ratios through electrochemical deposition on defective TiOxnanotube arrays.Denitrification experiments demonstrated that the Pd_(1)Cu_(1)/TiO_(x)catalyst exhibited the highest(NO_(3^(–)))removal rate(81.2%)and N_(2)selectivity(67.2%)among all tested catalysts.Leveraging the exceptional light-responsive property of TiO_(x),the introduction of light energy as an assisting factor in electrocatalysis further augmented the(NO_(3^(–)))treatment rate,resulting in a higher(NO_(3^(–)))removal rate of 95.1%and N_(2)selectivity of approximately 90%.Compared to individual electrocatalysis and photocatalysis systems,the overpotential for the catalytic interface active*H formation in the photo-assisted electrocatalysis system was remarkably reduced,thus accelerating electron migration and promoting(NO_(3^(–)))reduction kinetics.Economic analysis revealed an energy consumption of 2.74 k Wh/mol and a corresponding energy consumption per order(EEO)of 0.79 k Wh/m^(3)for the Pd_(1)Cu_(1)/TiOxcatalyst to reduce 25.2 mg/L of(NO_(3^(–)))-N in water to N_(2),showcasing remarkable competitiveness and economic advantages over other water treatment technologies.This study developed the PdCu/TiOxelectrocatalysts with high(NO_(3^(–)))removal rates and N_(2)selectivity,particularly when combined with light energy,the efficiency and selectivity were significantly enhanced,offering a competitive and economically viable solution for wastewater treatment.
基金supported by SINOPEC Research Institute of Petroleum Processing Co.Ltd and funded by the Sinopec Foreign Cooperation Project(33600000‐22‐ZC0699‐0169)National Natural Science Foundation of China(NSFC,22402072)Natural Science Foundation of Shandong Province(ZR2023QB025).
文摘Replacing the energy‐intensive Haber–Bosch process with electrocatalytic urea synthesis from waste NO_(3)−and CO_(2) is hindered by kinetic competition from undesirable^(*)NOH‐mediated NH_(3) formation.Herein,we design a spin‐polarized PdCu/TiO_(2)‐x catalyst with oxygen vacancies(OV)to enable regioselective C‐N coupling.The OV engineering synergistically modulates NO adsorption configurations and suppresses oxygen‐terminal hydrogenation(NO→^(*)NOH),redirecting the pathway toward^(*)NO→^(*)HNO for urea formation.This dynamic control achieves a record urea yield of 37.84 mmol h^(−1) g^(−1) at low voltage,outperforming most reported catalysts.Operando attenuated total reflection–surface‐enhanced infrared absorption spectroscopy(ATR‐SEIRAS)and density functional theory(DFT)studies confirm that OV enhance NO_(3)−/CO_(2) co‐adsorption,accelerate the rate‐determining NO→HNO step,and stabilize dispersed PdCu clusters for increased active sites.This spin‐defect synergy offers a sustainable strategy for electro‐synthesizing urea while valorizing environmental pollutants.
文摘如何构筑高性能的电催化剂是提高卤代有机污染物电催化还原去除的关键.本研究通过化学共还原的方法制备出钯铜(PdCu)纳米合金催化剂,通过扫描电子显微镜(SEM)、高分辨率透射电子显微镜(HRTEM)、能量色散X射线光谱(EDX)、X射线衍射(XRD)、X射线光电子能谱(XPS)、线性扫描伏安法(LSV)和电化学阻抗谱(EIS)等方法对其微观结构和电化学性能进行表征,并探究PdCu纳米合金催化剂对抗生素氟苯尼考(Florfenicol,FLO)电催化还原的降解机理.实验结果表明,所制备的PdCu纳米合金催化剂中Pd、Cu纳米颗粒分布均匀,具有优异的电化学还原性能和动力学性能以及快速的电子转移速率.PdCu纳米合金催化剂在-1.3 V vs.Hg/Hg_(2)SO_(4)下,120 min内对FLO的去除率高达97.5%,远高于纯Pd(82.9%)、纯Cu(67.4%)金属纳米颗粒催化剂的去除率,中性pH更有利于FLO的降解.叔丁醇淬灭实验表明,吸附态原子氢在电催化还原去除FLO过程中起重要作用.使用液质联用仪(LC-MS/MS)对FLO降解后的产物进行半定量分析表明,在PdCu纳米合金催化剂上FLO的电催化还原是一个逐步脱卤的过程,在实现完全脱氯后再进行脱氟.本研究为电催化高效还原卤代有机污染物提供了一种具有应用潜力的催化剂方案.
基金financially supported by the National Natural Science Foundation of China (No.51901197, 51971184 and 51771157)the Open Fund of Fujian Provincial Key Laboratory of Eco-Industrial Green Technology in Wuyi University (No.WYKF-EIGT2021-6)
文摘Developing efficient and stable bimetallic Pdbased anode electrocatalysts toward formic acid oxidation(FAO)is of great significance for commercial applications of direct formic acid fuel cells(DFAFCs).Herein,we report a facile synthesis approach to fabricate PdCu nanoclusters(NCs)catalysts with granular-film structure.The introduction of Cu can adjust the electronic structure and d-band center of Pd,which can improve the catalytic performance of the catalysts.Compared with Pd NCs catalyst,the catalytic durability and activity of PdCu NCs catalysts for FAO are greatly improved.The order for catalytic activity of NC metals is Pd_(85)Cu_(15)NCs>Pd_(70)Cu_(30)NCs>Pd NCs.The maximum mass activity can be acquired with the Pd_(85)Cu_(15)NCs catalyst,which is about1.7 times that of the Pd NCs catalyst.And Pd_(85)Cu_(15)NCs catalyst still maintains the highest catalytic current density after 50 cycles,indicating that Pd_(85)Cu_(15)NCs catalyst has the best durability and electrocatalytic activity for FAO.Our work provides a new prospect for the design of highly efficient anode catalysts materials for DFAFCs.
基金the financial support from the Program for Innovative Research Team in University of Henan Province(21IRTSTHN009)Science and Technology Fund of Henan Province(225200810051)Natural Science Foundation of Henan Province(222300420406)。
文摘The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is responsible for the adsorption and activation of CO_(2)and the generation of CO and H2via side reactions often lead to poor efficiency and low selectivity of the catalyst.Herein,Cu,Pd,and PdCu metal clusters cocatalyst-anchored defective TiO_(2)nanotubes(Cu/TiO_(2)-SBO,Pd/TiO_(2)-SBO,and Pd1Cu1/TiO_(2)-SBO)were designed via a simple solution impregnation reduction and applied for photocatalytic conversion of CO_(2)to CH_(4).The Pd1Cu1/TiO_(2)-SBO photocatalyst exhibits excellent catalytic performance among the other catalysts for photoreduction of CO_(2)into CH_(4).More interestingly,the product selectivity of CH_(4)reaches up to 100%with a rate of 25μmol g^(-1)h^(-1).In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)simulations indicate that the main reasons for the high selectivity of CH_(4)are attributed to the PdCu alloy and oxygen vacancies,which jointly enhance the photoinduced carrier separation and lower energy barriers of key intermediates.Moreover,due to the tunable d-band center of the Cu site in the PdCu alloy,the generated intermediates can be well prevented from poisoning and promoted to participate in further reactions.Hopefully,the current study will provide insight into the development of new,highly selective photocatalysts for the visible light-catalytic reduction of CO_(2)into CH_(4).
基金supported by the United Arab Emirates University under a Grant number FOS/IRG-23/11
文摘Transport of charge carriers in percolating nanocluster devices based on bimetallic PdCu nanoclusters was investigated in this work. The device was fabricated by self-assembly of the nanoclusters between electrical electrodes inside an ultra-high vacuum compatible system. The average size of the produced nanoclusters was 7.3 nm, and the composition was Pdo.77Cuo.23. Systematic in situ current-voltage measurements as a function of temperature were per- formed which provide a conductance-temperature profile. The results are explained in terms of the charge carriers＇ tunneling through small potential barriers at the junctions between nanoclusters. The results predict the size of the nanoclusters as well as the magnitude of the potential difference of the tunneling barriers. This investigation helps understanding the nature of the interface between the nanoclusters and the charge carrier transport within those devices to be utilized for optimizing gas sensing properties of PdCu nanocluster devices.
文摘Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.
基金financially supported by the Major Fundamental Research of Natural Science Foundation of Shandong Province(ZR2022ZD10)National Natural Science Foundation of China(22478211,22372017)+2 种基金Postdoctoral Fellowship Program of CPSF(GZC20231193)Liaoning Binhai Laboratory(LBLG-2024-10)Qingdao Postdoctoral Applied Research Project(QDBSH20240102068)。
文摘Electrocatalysis,a form of heterogeneous catalysis,is closely associated with both catalyst properties and the catalyst/electrolyte interfacial microenvironment.Herein,we rationally design and synthesize a unique PdCu nano-sea urchins(PdCu NSUs)featured with high-curvature nanotips,by which the interfacial microenvironment is expected to be tailored to the electrocatalytic reactions.PdCu NSUs exhibit excellent activity for ethanol electrooxidation,with a specific activity of 4.11 mA cm^(-2)and a mass activity of 2.24 mAμg_(Pd)^(-1),and a high Faraday efficiency(FE)of 96.4%toward acetic acid.COMSOL finite element simulations confirm that the unique nanotips could induce a local electric field due to the accumulation of positive charges in the nanotips,resulting in enrichment of OH^(-)at the catalyst surface to promote the formation of Pd-OH_(ads),a species required by ethanol dehydrogenation.Furthermore,DFT calculations and in-situ electrochemical Fourier transform infrared spectroscopy discover that the d-band center of Pd significantly downshifts in PdCu alloy,which facilitates the desorption of the produced acetic acid.This work provides a new electrocata lytic material with high-curvature nanotips,and also clarifies how the material morphology,by inducing local electric fields,affects the interfacial microenvironment and thus the catalytic activity and selectivity.
基金This research was supported in part by the National Natural Science Foundation of China （Nos. 21475007, 21275015 and 21505003）, and the Fundamental Research Funds for the Central Universities （Nos. YS1406, buctrc201507 and buctrc201608）. We also thank the support from the Innovation and Promotion Project of Beijing University of Chemical Technology, the Public Hatching Platform for Recruited Talents of Beijing University of Chemical Technology, the High- Level Faculty Program of Beijing University of Chemical Technology （No. buctrc201325）, and BUCT Fund for Disciplines Construction and Development （No. XK1526）.
文摘Suzuki-Miyaura reactions, involving the activation of carbon-halogen bonds, especially C-C1 bonds, have drawn widespread attention because of their huge industrial potential. However, these reactions are dependent on the development of highly active and stable catalysts. Herein, we developed a convenient one-pot wet route to synthesize PdxCuy bimetallic nanocrystals for the Suzuki-Miyaura reaction. By introducing Cu, an earth-abundant element, the catalytic activity was greatly enhanced while the amount of Pd required was reduced. PdxCuy nanocrystals of different compositions, including PdBCu, Pd2Cu, PdCu, PdCu2, and PdCu3, were successfully synthesized by tuning the Pd：Cu ratio. Their catalytic performance in Suzuki-Miyaura reactions between phenylboronic acid and halobenzenes （iodo-, bromo-, or chlorobenzene） showed that PdCua nanocatalyst demonstrated the best efficacy.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.22279118,22279117,52071135,51871090,and U1804135)the Fundamental Research Funds for the Universities of Henan Province(No.NSFRF220201).
文摘The design of high-performance catalysts is the key to the efficient utilization of hydrogen energy.In this work,a PdCu nanoalloy was successfully anchored on TiO_(2)encapsulated with carbon to construct a catalyst.Outstanding kinetics of the hydrolysis of ammonia borane(turnover frequency of 279 mol·min^(-1·)mol_(Pd)^(-1))ranking the third place among Pd-based catalysts was achieved in the absence of alkali.Both experimental research and theoretical calculations reveal a lower activation energy of the B-H bond on the PdCu nanoalloy catalyst than that on pristine Pd and a lower activation energy of the O-H bond than that on pristine Cu.The redistribution of d electron and the shift of the d-band center play a critical role in increasing the electron density of Pd and improving the catalytic performances of Pd_(0.1)Cu_(0.9)/TiO_(2)-porous carbon(Pd_(0.1)Cu_(0.9)/T-PC).This work provides novel insights into highly dual-active alloys and sheds light on the mechanism of dual-active sites in promoting borohydride hydrolysis.
基金financial support provided by the National Natural Science Foundation of China(grant No.22072164)the Research Fund of Shenyang National Laboratory for Materials Science.
文摘The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly dependent on the activity and stable of catalysts.Herein,the support morphology-dependent catalytic performance of SMC reactions was investigated.The truncated hexagonal bipyramid(α-Fe_(2)O_(3)-O)and rod-shaped morphologies of alpha-Fe_(2)O_(3)(α-Fe_(2)O_(3)-R)were used as support to prepare PdCu nanoparticles(NPs)catalysts by NaBH_(4) reduction method.For PdCu/α-Fe_(2)O_(3)-R catalysts,the smaller size of PdCu NPs and more low coordination Pd sites leading to its superior catalytic performance for SMC reactions.Furthermore,it can be easily recycled through centrifugation and reused several times without obvious loss on its catalytic performance.Identical location transmission electron microscopy method was used to investigate the structural evolution of PdCu/α-Fe_(2)O_(3)-R catalysts.The results found that its structure almost unchanged during the catalytic reaction.
