The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particula...The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particular, the influence of the secondary metal on the electrochemical performance as well as on the product distribution was studied. For that purpose, Pt X/C electrocatalysts(where X corresponds to Cu, Co, Ni and Ru) were synthesized by the modified polyol method and tested in both half-cell and proton exchange membrane(PEM) cell configurations. Characterization results showed that incorporation of Ni and Co into the Pt matrix enhances the morphological properties of the material, providing smaller crystallite sizes, higher active surface areas and hence, better dispersion when comparing to Ru and Cu-based electrocatalysts. Ethanol oxidation reaction(EOR) was evaluated by cyclic, linear voltammetry and chronopotentiometry assays. Pt Co/C and Pt Ni/C exhibited the highest electrocatalytic activity at high polarization levels, which translate into an improvement of more than 30%(up to 1050 m A cm^(-2)) in the hydrogen production and chemical yields. On the other hand, Pt Ru/C results more advantageous for a lower potential interval(<0.85 V) promoting the acetic acid production despite sacrificing ethanol conversion. Pt Cu/C presented the lowest results in both electrochemical performance and product distribution. Such differences in the electrochemical performance can be rationalized in terms of the synergistic effect between both metals(particle size distribution, grade of dispersion and hydrophilic behavior), which demonstrate that the incorporation of a different secondary metal plays an essential role in the EOR development.展开更多
Electrochemical water splitting for hydrogen(H_(2))production represents a promising technology to achieve carbon neutrality.However,its widespread application is severely limited by the sluggish kinetics and high the...Electrochemical water splitting for hydrogen(H_(2))production represents a promising technology to achieve carbon neutrality.However,its widespread application is severely limited by the sluggish kinetics and high theoretical potential(1.23 V)of the anodic oxygen evolution reaction(OER),which dominates the overall energy consumption.Hybrid water splitting(HWS)systems,which integrate thermodynamically more favorable anodic oxidation reactions of small molecules with the cathodic hydrogen evolution reaction(HER),provide an innovative approach for efficient and energy-saving H_(2)production.Crucially,achieving operation at industrially relevant high current densities(>200 mA·cm^(-2))is paramount for the practical implementation of these HWS systems.This review systematically summarizes recent advances in the development of high-performance anodic electrocatalysts for high-current-density applications.Key design strategies of anodic electrocatalysts are elaborated,including(i)surface chemistry engineering(e.g.,elemental doping,defect/strain/phase engineering,heterostructure construction)to optimize electronic structure and intermediates adsorption energetics;(ii)micro-/nano-structure design(e.g.,nanowires,nanosheets,microspheres,aligned-channel electrodes)to enhance mass transport and expose active sites;and(iii)catalyst-electrolyte interface tuning(e.g.,leveraging local electric fields,pH effects,introducing adsorbed anions)to regulate reactant concentrations and reaction pathways.We then comprehensively discuss the coupling of various small molecules(e.g.,urea,hydrazine,methanol,ethanol,glycerol,aldehyde,glucose,amine and sulfion)oxidation reactions with the HER for efficient and energy-saving H_(2)production under high current density conditions,with a particular focus on mitigating the competition from the OER.Finally,we present perspectives on the remaining challenges and future research directions,including the rational design of catalysts with high intrinsic activity and selectivity,in-depth mechanistic investigations using advanced in situ/operando techniques,the development of efficient flow reactors and membrane electrode assemblies for industrial operation,and strategies to enhance long-term stability.This review aims to provide valuable insights for the advancement of hybrid water splitting systems toward large-scale,cost-efficient and energy-saving H_(2)production.展开更多
Herein,high-valence-state Mn(V)oxide,barium manganate(V)(Ba_(3)(MnO_(4))_(2)),is examined as an anode electrocatalyst of a H^(+)-conducting solid oxide steam electrolysis cell(H-SOEC).Ba_(3)(MnO_(4))_(2)comprises C_(3...Herein,high-valence-state Mn(V)oxide,barium manganate(V)(Ba_(3)(MnO_(4))_(2)),is examined as an anode electrocatalyst of a H^(+)-conducting solid oxide steam electrolysis cell(H-SOEC).Ba_(3)(MnO_(4))_(2)comprises C_(3v)-symmetric MnO_(4)_(3)-oxo-anions with three long Mn-O bonds and one short Mn-O bond at room temperature.Ba_(3)(MnO_(4))_(2)caused a conductivity jump by one order of magnitude at approximately 600℃owing to the antiferromagnetic/paramagnetic phase transition,accompanied by a shape change of the tetrahedral MnO_(4)_(3)-anions from C_(3v)to Td symmetry,as confirmed by the electrical conductivity measurements and the extended X-ray absorption fine structure at an elevated temperature.Hence,the Ba_(3)(MnO_(4))_(2)base anode of the H-SOEC exhibited improved performance,with anode polarization resistances being lower than those of Sm0.5Sr0.5CoO_(3),a well-known H-SOEC anode material.Impedance analysis in terms of oxygen and water partial pressure revealed that the superior performance of the Ba_(3)(MnO_(4))_(2)base anode can be attributed to the extended reaction area.Since abundant unoccupied 3d states of the high-valence-state Mn5+cations are favorable for charge transfer interactions with water electron donors,thereby facilitating water adsorption,the oxygen evolution reaction could occur directly over the electrode surface,and thus the reaction sites were not limited to the gas-electrode-electrolyte triple phase boundary.展开更多
Ni-based materials have emerged as promising anode electrocatalysts that can replace noble metals for the methanol oxidation reaction(MOR).However,the potential applications of Ni-based metal–organic gels(Ni-MOGs)in ...Ni-based materials have emerged as promising anode electrocatalysts that can replace noble metals for the methanol oxidation reaction(MOR).However,the potential applications of Ni-based metal–organic gels(Ni-MOGs)in MOR have rarely been recognized.In this study,using the readily prepared Al-MOG(MIL-53(Al))without MOR activity as a template,we fabricated AlNi-MOG and AlNi-based trimetallic MOGs(Cu,Co and Fe)by a simple solvothermal method,which could be directly used as electrocatalysts for the MOR.Among them,the as-obtained AlNiCu-MOG exhibited better MOR activity with an area-specific peak current density of 17.1 mA cm^(−2)than AlNi-MOG(11.46 mA cm^(−2)),which could be attributed to the electron coupling between Ni and Cu.Moreover,the addition of the conductive material acetylene black(AB)could immensely increase the electric conductivity of AlNiCu-MOG,leading to its improved MOR activity with a peak current density of 33.24 mA cm^(−2).These results represent an important first step towards the application of MOGs in the MOR.展开更多
The development of anodic electrocatalysts toward the oxygen evolution reaction(OER)in harsh acidic environments faces significant challenges of low efficiency,instability and high cost.Ru-based oxides exhibit remarka...The development of anodic electrocatalysts toward the oxygen evolution reaction(OER)in harsh acidic environments faces significant challenges of low efficiency,instability and high cost.Ru-based oxides exhibit remarkable initial activity toward the OER,but the presence of soluble high-valence oxygenvacancy intermediates can accelerate the dissolution of Ru species.In this study,a triple Sr2CaRu2IrO9 perovskite oxide electrocatalyst has been successfully synthesized,demonstrating a low overpotential of 172 mV at 10 mA cm^(-2)and excellent stability for over 75 hours.The introduction of dual-site heteroatoms leads to the generation of oxygen vacancies,which control the excessive lattice oxygen participating in the OER via the lattice oxygen oxidation mechanism(LOM).This effectively prevents the excessive oxidation of Ru to form soluble Ru^(>4+)species.Density functional theory(DFT)calculations show that the negative shift of O 2p and Ru 4d band centers weakens the covalency of Ru-O,optimizes the adsorption energy of oxygen intermediates,and thus improves the inherent catalytic activity and stability.展开更多
This article presents a strategy for enhancing the catalytic performance and stability of anodic electrocatalysts in proton exchange membrane (PEM) water splitting. PEM water splitting is a sustainable method for prod...This article presents a strategy for enhancing the catalytic performance and stability of anodic electrocatalysts in proton exchange membrane (PEM) water splitting. PEM water splitting is a sustainable method for producing hydrogen and oxygen from water utilizing electrocatalysts. However, the performance and stability of the anodic electrocatalysts employed in this process are crucial for its commercialization due to harsh condition causing low stability. The main focus in this review article is the strategies for improving the catalytic performance as well as stability of the anodic electrocatalysts, such as doping with heteroatoms, and alloying with other metals. The results demonstrate that these modifications can significantly enhance the catalytic performance and stability of anodic electrocatalysts in PEM water splitting. These strategies open new possibilities for the development of efficient and stable electrocatalysts for PEM water splitting, paving the way for its commercialization and widespread use in clean energy applications.展开更多
基金We gratefully acknowledge the Spanish Ministry of Science and Innovation(project PID2019-107499RB-100 and FPI grant BES-2017-081181)for the financial support.
文摘The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particular, the influence of the secondary metal on the electrochemical performance as well as on the product distribution was studied. For that purpose, Pt X/C electrocatalysts(where X corresponds to Cu, Co, Ni and Ru) were synthesized by the modified polyol method and tested in both half-cell and proton exchange membrane(PEM) cell configurations. Characterization results showed that incorporation of Ni and Co into the Pt matrix enhances the morphological properties of the material, providing smaller crystallite sizes, higher active surface areas and hence, better dispersion when comparing to Ru and Cu-based electrocatalysts. Ethanol oxidation reaction(EOR) was evaluated by cyclic, linear voltammetry and chronopotentiometry assays. Pt Co/C and Pt Ni/C exhibited the highest electrocatalytic activity at high polarization levels, which translate into an improvement of more than 30%(up to 1050 m A cm^(-2)) in the hydrogen production and chemical yields. On the other hand, Pt Ru/C results more advantageous for a lower potential interval(<0.85 V) promoting the acetic acid production despite sacrificing ethanol conversion. Pt Cu/C presented the lowest results in both electrochemical performance and product distribution. Such differences in the electrochemical performance can be rationalized in terms of the synergistic effect between both metals(particle size distribution, grade of dispersion and hydrophilic behavior), which demonstrate that the incorporation of a different secondary metal plays an essential role in the EOR development.
基金support from the National Natural Science Foundation of China(Grant No.92163116)Major Program of the Natural Science Foundation of Hunan Province(Grant No.2021JC0006).
文摘Electrochemical water splitting for hydrogen(H_(2))production represents a promising technology to achieve carbon neutrality.However,its widespread application is severely limited by the sluggish kinetics and high theoretical potential(1.23 V)of the anodic oxygen evolution reaction(OER),which dominates the overall energy consumption.Hybrid water splitting(HWS)systems,which integrate thermodynamically more favorable anodic oxidation reactions of small molecules with the cathodic hydrogen evolution reaction(HER),provide an innovative approach for efficient and energy-saving H_(2)production.Crucially,achieving operation at industrially relevant high current densities(>200 mA·cm^(-2))is paramount for the practical implementation of these HWS systems.This review systematically summarizes recent advances in the development of high-performance anodic electrocatalysts for high-current-density applications.Key design strategies of anodic electrocatalysts are elaborated,including(i)surface chemistry engineering(e.g.,elemental doping,defect/strain/phase engineering,heterostructure construction)to optimize electronic structure and intermediates adsorption energetics;(ii)micro-/nano-structure design(e.g.,nanowires,nanosheets,microspheres,aligned-channel electrodes)to enhance mass transport and expose active sites;and(iii)catalyst-electrolyte interface tuning(e.g.,leveraging local electric fields,pH effects,introducing adsorbed anions)to regulate reactant concentrations and reaction pathways.We then comprehensively discuss the coupling of various small molecules(e.g.,urea,hydrazine,methanol,ethanol,glycerol,aldehyde,glucose,amine and sulfion)oxidation reactions with the HER for efficient and energy-saving H_(2)production under high current density conditions,with a particular focus on mitigating the competition from the OER.Finally,we present perspectives on the remaining challenges and future research directions,including the rational design of catalysts with high intrinsic activity and selectivity,in-depth mechanistic investigations using advanced in situ/operando techniques,the development of efficient flow reactors and membrane electrode assemblies for industrial operation,and strategies to enhance long-term stability.This review aims to provide valuable insights for the advancement of hybrid water splitting systems toward large-scale,cost-efficient and energy-saving H_(2)production.
基金supported by the JST MIRAI“Realization of a low carbon society,global issue”,No.JPMJM17E7the JSPS KAKENHI:Grant-in-Aid for Scientific Research(B),No.18H02066the“Nanotechnology Platform”program of the MEXT Japan,XAFS measurements were performed with the approval of SPring-8(No.2017B1288).
文摘Herein,high-valence-state Mn(V)oxide,barium manganate(V)(Ba_(3)(MnO_(4))_(2)),is examined as an anode electrocatalyst of a H^(+)-conducting solid oxide steam electrolysis cell(H-SOEC).Ba_(3)(MnO_(4))_(2)comprises C_(3v)-symmetric MnO_(4)_(3)-oxo-anions with three long Mn-O bonds and one short Mn-O bond at room temperature.Ba_(3)(MnO_(4))_(2)caused a conductivity jump by one order of magnitude at approximately 600℃owing to the antiferromagnetic/paramagnetic phase transition,accompanied by a shape change of the tetrahedral MnO_(4)_(3)-anions from C_(3v)to Td symmetry,as confirmed by the electrical conductivity measurements and the extended X-ray absorption fine structure at an elevated temperature.Hence,the Ba_(3)(MnO_(4))_(2)base anode of the H-SOEC exhibited improved performance,with anode polarization resistances being lower than those of Sm0.5Sr0.5CoO_(3),a well-known H-SOEC anode material.Impedance analysis in terms of oxygen and water partial pressure revealed that the superior performance of the Ba_(3)(MnO_(4))_(2)base anode can be attributed to the extended reaction area.Since abundant unoccupied 3d states of the high-valence-state Mn5+cations are favorable for charge transfer interactions with water electron donors,thereby facilitating water adsorption,the oxygen evolution reaction could occur directly over the electrode surface,and thus the reaction sites were not limited to the gas-electrode-electrolyte triple phase boundary.
基金supported by the NSF of China(No.21971143,21805165,21673127 and 21671119)The 111 Project(D20015)ITOYMR in the Higher Education Institutions of Hubei Province(T201904).
文摘Ni-based materials have emerged as promising anode electrocatalysts that can replace noble metals for the methanol oxidation reaction(MOR).However,the potential applications of Ni-based metal–organic gels(Ni-MOGs)in MOR have rarely been recognized.In this study,using the readily prepared Al-MOG(MIL-53(Al))without MOR activity as a template,we fabricated AlNi-MOG and AlNi-based trimetallic MOGs(Cu,Co and Fe)by a simple solvothermal method,which could be directly used as electrocatalysts for the MOR.Among them,the as-obtained AlNiCu-MOG exhibited better MOR activity with an area-specific peak current density of 17.1 mA cm^(−2)than AlNi-MOG(11.46 mA cm^(−2)),which could be attributed to the electron coupling between Ni and Cu.Moreover,the addition of the conductive material acetylene black(AB)could immensely increase the electric conductivity of AlNiCu-MOG,leading to its improved MOR activity with a peak current density of 33.24 mA cm^(−2).These results represent an important first step towards the application of MOGs in the MOR.
基金the financial support from the National Natural Science Foundation of China(NSFC,grant no.52073283,22078124,and 22378158)Natural Science Foundation Project of Jilin Province(YDZJ202201ZYTS336)+4 种基金Key Projects of Science and Technology Development Plan of Jilin Province(20220201125GX)the Project of Education Department of Jilin Province(JJKH20221155KJ)the Project of Jilin Province Development and Reform Commission(2023C032-2 and 2023C032-5)the Program for the Development of Science and Technology of Jilin Province(20230508040RC)the Science and Technology Innovation Center Project of Jilin Province(YDZJ202102CXJD049).
文摘The development of anodic electrocatalysts toward the oxygen evolution reaction(OER)in harsh acidic environments faces significant challenges of low efficiency,instability and high cost.Ru-based oxides exhibit remarkable initial activity toward the OER,but the presence of soluble high-valence oxygenvacancy intermediates can accelerate the dissolution of Ru species.In this study,a triple Sr2CaRu2IrO9 perovskite oxide electrocatalyst has been successfully synthesized,demonstrating a low overpotential of 172 mV at 10 mA cm^(-2)and excellent stability for over 75 hours.The introduction of dual-site heteroatoms leads to the generation of oxygen vacancies,which control the excessive lattice oxygen participating in the OER via the lattice oxygen oxidation mechanism(LOM).This effectively prevents the excessive oxidation of Ru to form soluble Ru^(>4+)species.Density functional theory(DFT)calculations show that the negative shift of O 2p and Ru 4d band centers weakens the covalency of Ru-O,optimizes the adsorption energy of oxygen intermediates,and thus improves the inherent catalytic activity and stability.
基金supported by the National Natural Science Foundation of China(No.22209126).
文摘This article presents a strategy for enhancing the catalytic performance and stability of anodic electrocatalysts in proton exchange membrane (PEM) water splitting. PEM water splitting is a sustainable method for producing hydrogen and oxygen from water utilizing electrocatalysts. However, the performance and stability of the anodic electrocatalysts employed in this process are crucial for its commercialization due to harsh condition causing low stability. The main focus in this review article is the strategies for improving the catalytic performance as well as stability of the anodic electrocatalysts, such as doping with heteroatoms, and alloying with other metals. The results demonstrate that these modifications can significantly enhance the catalytic performance and stability of anodic electrocatalysts in PEM water splitting. These strategies open new possibilities for the development of efficient and stable electrocatalysts for PEM water splitting, paving the way for its commercialization and widespread use in clean energy applications.
