Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, ...Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, including high cost, insufficient power density, and limited performance durability. A kinetically sluggish oxygen reduction reaction(ORR) is primarily responsible for these issues. The development of advanced Pt-based catalysts is crucial for solving these problems if the large-scale application of PEMFCs is to be realized. In this review, we summarize the recent progress in the development of Pt M alloy(M = Fe, Co, Ni, etc.) catalysts with an emphasis on ordered Pt M intermetallic catalysts, which exhibit significantly enhanced activity and stability. In addition to exploring the intrinsic catalytic performance in traditional aqueous electrolytes via engineering nanostructures, morphologies, and crystallinity of Pt M particles, we highlight recent efforts to study catalysts under real fuel cell environments by the membrane electrode assembly(MEA).展开更多
Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER ...Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER catalytic activity of the single-atom catalysts(SACs)composed of 4d/5d period transition metal(TM)atoms embedded on MBene substrates(TM-M_(2)B_(2)O_(2),M=Ti,Mo,and W).We found that TM dominates the catalytic activity compared to the MBene substrates.The SACs embedded with Rh,Pd,Au,and Ir exhibit excellent ORR or OER catalytic activity.Specifically,Rh-Mo2B2O2and Rh-W2B2O2are promising bifunctional catalysts with ultra-low ORR/OER overpotentials of 0.39/0.21 V and0.19/0.32 V,respectively,lower than that of Pt/RuO_(2)(0.45/0.42 V).Importantly,through machine learning,the models containing 10 element features of SACs were developed to quickly and accurately identify the superior ORR and OER electrocatalysts.Our findings provide several promising SACs for ORR and OER,and offer effective models for catalyst design.展开更多
The application of electrocatalysts for the oxygen reduction reaction(ORR) is vital in a variety of energy conversion technologies. Exploring low-cost ORR catalysts with high activity and long-term stability is highly...The application of electrocatalysts for the oxygen reduction reaction(ORR) is vital in a variety of energy conversion technologies. Exploring low-cost ORR catalysts with high activity and long-term stability is highly desirable, although it still remains challenging. Herein, we report a facile and reliable route to convert ZIF-8 modified by Fe-phenanthroline into Fe-incorporated and N-doped carbon dodecahedron nanoarchitecture(Fe-NCDNA), in which carbon nanosheets are formed in situ as the building blocks with uniform Fe-N-C species decoration. Systematic electrochemical studies demonstrate that the as-synthesized Fe-NCDNA electrocatalyst possesses highly attractive catalytic features toward the ORR in terms of activity and durability in both alkaline and neutral media. The Zn-air battery with the optimal Fe-NCDNA catalyst as the cathode performs impressively, delivering a power density of 184 m W cm^–2 and a specific capacity of 801 m Ah g^–1;thus, it exhibits great competitive advantages over those of the Zn-air devices employing a Pt-based cathode electrocatalyst.展开更多
Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their m...Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel cells.Herein,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal method.The addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired structure.The Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C catalyst.Meanwhile,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ORR.Furthermore,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for MOR.The superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy structure.The novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.展开更多
Facile mass transport channel and accessible active sites are crucial for binder-free air electrode catalysts in rechargeable flexible zinc-air battery(ZAB).Herein,a ZnS/NH3 dual-assisted pyrolysis strategy is propose...Facile mass transport channel and accessible active sites are crucial for binder-free air electrode catalysts in rechargeable flexible zinc-air battery(ZAB).Herein,a ZnS/NH3 dual-assisted pyrolysis strategy is proposed to prepare N/S-doped hierarchical porous bamboo carbon cloth(HP-NS-BCC)as binder-free air electrode catalyst for ZAB.BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom-doping and construct the hierarchical porous structure.ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S-doping and optimize the macro/meso/micropores structure of carbon fibers.Benefiting from the highly-exposed N/S-induced sites with enhanced intrinsic activity,the optimized mass transport of biocarbon fibers,as well as the ultra-large specific surface area of 2436.1 m^(2)·g^(-1),the resultant HP-NS-BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction.When applied to rechargeable aqueous ZABs,it achieves a significant peak power density of 249.1 mW·cm^(-2).As binder-free air electrode catalyst,the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V,showcasing promising applications in flexible electronic devices.展开更多
There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNT...There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNTs composite have gained increasing attention. In this paper, the 3-D hollow sphere MnO_2 nanotube-supported Co_3O_4 nanoparticles and its carbon nanotubes hybrid material(Co_3 O_4/MnO_2-CNTs) have been synthesized via a simple co-precipitation method combined with post-heat treatment. The morphology and composition of the catalysts are thoroughly analyzed through SEM, TEM, TEM-mapping, XRD, EDX and XPS. In comparison with the commercial 20% Pt/C, Co_3O_4/MnO_2,bare MnO_2 nanotubes and CNTs, the hybrid Co_3O_4/MnO_2-CNTs-350 exhibits perfect bi-functional catalytic activity toward oxygen reduction reaction and oxygen evolution reaction under alkaline condition(0.1 M KOH). Therefore, high cell performances are achieved which result in an appropriate open circuit voltage(～1.47 V),a high discharge peak power density(340 mW cm^(-2)) and a large specific capacity(775 mAh g^(-1) at 10 mA cm^(-2)) for the primary Zn-air battery, a small charge-discharge voltage gap and a high cycle-life(504 cycles at 10 mA cm^(-2) with 10 min per cycle) for the rechargeable Zn-air battery. In particular, the simple synthesis method is suitable for a large-scale production of this bifunctional material due to a green, cost effective and readily available process.展开更多
Rare earth metal based perovskite emerges as important catalytic material for energy production and storage.These ABO_(3) type materials are now the focus of research in the field of oxygen reduction and evolution rea...Rare earth metal based perovskite emerges as important catalytic material for energy production and storage.These ABO_(3) type materials are now the focus of research in the field of oxygen reduction and evolution reactions.Here,in this work we evaluated the oxygen reduction properties of the synthesized one-dimensional REMnO_(3)(RE=Pr,Nd,Sm,Eu and Gd).The one-dimensional REMnO_(3) prepared by the hydrothermal synthesis route results in pure phase perovskite on calcinations.The perovskite was characte rized with X-ray diffraction,Fourier transform-infrared(FT-IR),field emission-scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS).The oxygen reduction reaction activities were investigated with the help of electrochemical workstation that consists of three-electrode system immersed in 0.1 mol/L KOH electrolyte solution saturated with oxygen.The Koutechy-Levich plot obtained from rotating ring disk electrode shows all the prepared catalysts follow 4e^(-)processes during oxygen reduction.The effect of "A" site cation variation in REMnO3 on oxygen reduction reaction is discussed.SmMnO_(3) showed better onset potential for oxygen reduction reaction among the prepared rare earth perovskite.SmMnO_(3) having high RE:Mn ratio(A-site rich co mpositions) promotes oxygen reduction reaction(ORR) activity.All the perovs kites showed good oxygen reduction property with high stability and methanol tolerance.展开更多
Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte s...Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.展开更多
Silver nanoparticles（Ag NPs） were prepared by dealloying Mg-Ag alloy precursor. The obtained Ag NPs have an average ligament size of （50±10） nm. Electrocatalytic activity of Ag NPs towards oxygen reduction re...Silver nanoparticles（Ag NPs） were prepared by dealloying Mg-Ag alloy precursor. The obtained Ag NPs have an average ligament size of （50±10） nm. Electrocatalytic activity of Ag NPs towards oxygen reduction reaction（ORR） in 0.1 mol/L NaOH solution was assessed via cyclic voltammetry（CV）, rotating ring disk electrode（RRDE） techniques, and electrochemical impedance spectroscopy（EIS）. The electrochemical active area for the ORR was evaluated by means of the charge of the underpotential deposition（UPD） of lead（Pb） on Ag NPs. The CV results in- dicate that Ag NPs have a higher current density and more positive onset potential than the bulk Ag electrode. RRDE was employed to determine kinetic parameters for O2 reduction. Ag NPs exhibit a higher kinetic current density of 25.84 mA/cm2 and a rate constant of 5.45× 10^-2 cm/s at -0.35 V vs. Hg/HgO. The number of electrons（n） involved in ORR is close to 4. Further, EIS data show significantly low charge transfer resistances on the Ag NPs electrode. The results indicate that the prepared Ag NPs have a high activity and are promising catalyst for ORR in alkaline solution.展开更多
文摘Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, including high cost, insufficient power density, and limited performance durability. A kinetically sluggish oxygen reduction reaction(ORR) is primarily responsible for these issues. The development of advanced Pt-based catalysts is crucial for solving these problems if the large-scale application of PEMFCs is to be realized. In this review, we summarize the recent progress in the development of Pt M alloy(M = Fe, Co, Ni, etc.) catalysts with an emphasis on ordered Pt M intermetallic catalysts, which exhibit significantly enhanced activity and stability. In addition to exploring the intrinsic catalytic performance in traditional aqueous electrolytes via engineering nanostructures, morphologies, and crystallinity of Pt M particles, we highlight recent efforts to study catalysts under real fuel cell environments by the membrane electrode assembly(MEA).
基金supported by the National Key Research and Development Program of China(2022YFB3807200)
文摘Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER catalytic activity of the single-atom catalysts(SACs)composed of 4d/5d period transition metal(TM)atoms embedded on MBene substrates(TM-M_(2)B_(2)O_(2),M=Ti,Mo,and W).We found that TM dominates the catalytic activity compared to the MBene substrates.The SACs embedded with Rh,Pd,Au,and Ir exhibit excellent ORR or OER catalytic activity.Specifically,Rh-Mo2B2O2and Rh-W2B2O2are promising bifunctional catalysts with ultra-low ORR/OER overpotentials of 0.39/0.21 V and0.19/0.32 V,respectively,lower than that of Pt/RuO_(2)(0.45/0.42 V).Importantly,through machine learning,the models containing 10 element features of SACs were developed to quickly and accurately identify the superior ORR and OER electrocatalysts.Our findings provide several promising SACs for ORR and OER,and offer effective models for catalyst design.
文摘The application of electrocatalysts for the oxygen reduction reaction(ORR) is vital in a variety of energy conversion technologies. Exploring low-cost ORR catalysts with high activity and long-term stability is highly desirable, although it still remains challenging. Herein, we report a facile and reliable route to convert ZIF-8 modified by Fe-phenanthroline into Fe-incorporated and N-doped carbon dodecahedron nanoarchitecture(Fe-NCDNA), in which carbon nanosheets are formed in situ as the building blocks with uniform Fe-N-C species decoration. Systematic electrochemical studies demonstrate that the as-synthesized Fe-NCDNA electrocatalyst possesses highly attractive catalytic features toward the ORR in terms of activity and durability in both alkaline and neutral media. The Zn-air battery with the optimal Fe-NCDNA catalyst as the cathode performs impressively, delivering a power density of 184 m W cm^–2 and a specific capacity of 801 m Ah g^–1;thus, it exhibits great competitive advantages over those of the Zn-air devices employing a Pt-based cathode electrocatalyst.
文摘Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel cells.Herein,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal method.The addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired structure.The Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C catalyst.Meanwhile,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ORR.Furthermore,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for MOR.The superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy structure.The novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.52102260,22379056,52202243)the project funded by China Postdoctoral Science Foundation(Grant Nos.2022M711545,2022M711371)+1 种基金Research and Practice Innovation Plan of Postgraduate Training Innovation Project in Jiangsu Province(SJCX23_2156)Shanghai Frontiers Research Center of the Hadal Biosphere,SciTech Funding by CSPFTZ Lingang Special Area Marine Biomedical Innovation Platform.
文摘Facile mass transport channel and accessible active sites are crucial for binder-free air electrode catalysts in rechargeable flexible zinc-air battery(ZAB).Herein,a ZnS/NH3 dual-assisted pyrolysis strategy is proposed to prepare N/S-doped hierarchical porous bamboo carbon cloth(HP-NS-BCC)as binder-free air electrode catalyst for ZAB.BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom-doping and construct the hierarchical porous structure.ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S-doping and optimize the macro/meso/micropores structure of carbon fibers.Benefiting from the highly-exposed N/S-induced sites with enhanced intrinsic activity,the optimized mass transport of biocarbon fibers,as well as the ultra-large specific surface area of 2436.1 m^(2)·g^(-1),the resultant HP-NS-BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction.When applied to rechargeable aqueous ZABs,it achieves a significant peak power density of 249.1 mW·cm^(-2).As binder-free air electrode catalyst,the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V,showcasing promising applications in flexible electronic devices.
基金financial support from the National Natural Science Foundation of China (U1510120, 91645110)the Project of Introducing Overseas Intelligence High Education of China (2017-2018)+1 种基金the Graduate Thesis Innovation Foundation of Donghua University (EG2016034)the College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University
文摘There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNTs composite have gained increasing attention. In this paper, the 3-D hollow sphere MnO_2 nanotube-supported Co_3O_4 nanoparticles and its carbon nanotubes hybrid material(Co_3 O_4/MnO_2-CNTs) have been synthesized via a simple co-precipitation method combined with post-heat treatment. The morphology and composition of the catalysts are thoroughly analyzed through SEM, TEM, TEM-mapping, XRD, EDX and XPS. In comparison with the commercial 20% Pt/C, Co_3O_4/MnO_2,bare MnO_2 nanotubes and CNTs, the hybrid Co_3O_4/MnO_2-CNTs-350 exhibits perfect bi-functional catalytic activity toward oxygen reduction reaction and oxygen evolution reaction under alkaline condition(0.1 M KOH). Therefore, high cell performances are achieved which result in an appropriate open circuit voltage(～1.47 V),a high discharge peak power density(340 mW cm^(-2)) and a large specific capacity(775 mAh g^(-1) at 10 mA cm^(-2)) for the primary Zn-air battery, a small charge-discharge voltage gap and a high cycle-life(504 cycles at 10 mA cm^(-2) with 10 min per cycle) for the rechargeable Zn-air battery. In particular, the simple synthesis method is suitable for a large-scale production of this bifunctional material due to a green, cost effective and readily available process.
基金Project supported by Council of Scientific&Industrial Research (01/3089/21)the Centre of Excellence in Environment and Public Health by the Higher Education Department,Government of Odisha (Grant No.:26913/HED/HE-PTC-WB-02-17)。
文摘Rare earth metal based perovskite emerges as important catalytic material for energy production and storage.These ABO_(3) type materials are now the focus of research in the field of oxygen reduction and evolution reactions.Here,in this work we evaluated the oxygen reduction properties of the synthesized one-dimensional REMnO_(3)(RE=Pr,Nd,Sm,Eu and Gd).The one-dimensional REMnO_(3) prepared by the hydrothermal synthesis route results in pure phase perovskite on calcinations.The perovskite was characte rized with X-ray diffraction,Fourier transform-infrared(FT-IR),field emission-scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS).The oxygen reduction reaction activities were investigated with the help of electrochemical workstation that consists of three-electrode system immersed in 0.1 mol/L KOH electrolyte solution saturated with oxygen.The Koutechy-Levich plot obtained from rotating ring disk electrode shows all the prepared catalysts follow 4e^(-)processes during oxygen reduction.The effect of "A" site cation variation in REMnO3 on oxygen reduction reaction is discussed.SmMnO_(3) showed better onset potential for oxygen reduction reaction among the prepared rare earth perovskite.SmMnO_(3) having high RE:Mn ratio(A-site rich co mpositions) promotes oxygen reduction reaction(ORR) activity.All the perovs kites showed good oxygen reduction property with high stability and methanol tolerance.
基金supported by the National Natural Science Foundation of China(no.22372154,21972131).
文摘Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.
文摘Silver nanoparticles（Ag NPs） were prepared by dealloying Mg-Ag alloy precursor. The obtained Ag NPs have an average ligament size of （50±10） nm. Electrocatalytic activity of Ag NPs towards oxygen reduction reaction（ORR） in 0.1 mol/L NaOH solution was assessed via cyclic voltammetry（CV）, rotating ring disk electrode（RRDE） techniques, and electrochemical impedance spectroscopy（EIS）. The electrochemical active area for the ORR was evaluated by means of the charge of the underpotential deposition（UPD） of lead（Pb） on Ag NPs. The CV results in- dicate that Ag NPs have a higher current density and more positive onset potential than the bulk Ag electrode. RRDE was employed to determine kinetic parameters for O2 reduction. Ag NPs exhibit a higher kinetic current density of 25.84 mA/cm2 and a rate constant of 5.45× 10^-2 cm/s at -0.35 V vs. Hg/HgO. The number of electrons（n） involved in ORR is close to 4. Further, EIS data show significantly low charge transfer resistances on the Ag NPs electrode. The results indicate that the prepared Ag NPs have a high activity and are promising catalyst for ORR in alkaline solution.
