Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145925
Mariya Kadiri , Ayoub Tanji , Xuesong Fan , Peter K Liaw , T M Indra Mahlia , Hendra Hermawan
In the present work, the corrosion behavior and passive film properties of TiHfZrNbx (x = 0.2, 0.3 and 0.4) high-entropy alloys (HEAs) were evaluated under a simulated condition of a proton exchange membrane water electrolyser (PEMWE) in view of their application as bipolar plates. Results from electrochemical-impedance spectroscopy, cyclic- and static-polarizations evaluation revealed that in a 0.5 M H2SO4 + 5 ppm F– solution at 70 °C the HEAs exhibited about 600 times higher polarization resistance than that of CP-Ti, with the highest achieved at 79.57 kΩ.cm2 for TiHfZrNb0.2, leading to a sharp contrast in the corrosion-current density, 805.11 µA.cm-2 for the CP-Ti vs. 0.92 µA.cm-2 for the TiHfZrNb0.2, reflecting a far superior corrosion resistance of the HEAs. X-ray photoelectron spectroscopy analysis confirmed the formation of a multi-oxide passive film, predominantly by HfO2 > ZrO2 > TiO2, with a presence of Nb2O5 only in TiHfZrNb0.4, all possess an n-type semiconducting characteristic and a much lower electron-donor concentration in the HEAs than in the CP-Ti. The complementary analyses of scanning electron microscopy, atomic force microscopy and solution chemistry highlighted the synergistic effects of Hf, Zr, and Nb in enhancing protectiveness of the passive film, but the absence of Nb2O5 on the top surface of TiHfZrNb0.2 and TiHfZrNb0.3 indicated a small role of Nb toward passivation.
{"title":"Corrosion of TiHfZrNbx high-entropy alloys in a simulated condition of proton exchange membrane water electrolyser","authors":"Mariya Kadiri , Ayoub Tanji , Xuesong Fan , Peter K Liaw , T M Indra Mahlia , Hendra Hermawan","doi":"10.1016/j.electacta.2025.145925","DOIUrl":"10.1016/j.electacta.2025.145925","url":null,"abstract":"<div><div>In the present work, the corrosion behavior and passive film properties of TiHfZrNb<sub>x</sub> (<em>x</em> = 0.2, 0.3 and 0.4) high-entropy alloys (HEAs) were evaluated under a simulated condition of a proton exchange membrane water electrolyser (PEMWE) in view of their application as bipolar plates. Results from electrochemical-impedance spectroscopy, cyclic- and static-polarizations evaluation revealed that in a 0.5 M H<sub>2</sub>SO<sub>4</sub> + 5 ppm F<sup>–</sup> solution at 70 °C the HEAs exhibited about 600 times higher polarization resistance than that of CP-Ti, with the highest achieved at 79.57 kΩ.cm<sup>2</sup> for TiHfZrNb<sub>0.2</sub>, leading to a sharp contrast in the corrosion-current density, 805.11 µA.cm<sup>-2</sup> for the CP-Ti vs. 0.92 µA.cm<sup>-2</sup> for the TiHfZrNb<sub>0.2</sub>, reflecting a far superior corrosion resistance of the HEAs. X-ray photoelectron spectroscopy analysis confirmed the formation of a multi-oxide passive film, predominantly by HfO<sub>2</sub> > ZrO<sub>2</sub> > TiO<sub>2</sub>, with a presence of Nb<sub>2</sub>O<sub>5</sub> only in TiHfZrNb<sub>0.4</sub>, all possess an n-type semiconducting characteristic and a much lower electron-donor concentration in the HEAs than in the CP-Ti. The complementary analyses of scanning electron microscopy, atomic force microscopy and solution chemistry highlighted the synergistic effects of Hf, Zr, and Nb in enhancing protectiveness of the passive film, but the absence of Nb<sub>2</sub>O<sub>5</sub> on the top surface of TiHfZrNb<sub>0.2</sub> and TiHfZrNb<sub>0.3</sub> indicated a small role of Nb toward passivation.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145925"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145924
Ricoveer Shergill , Oliver Keattch , Bhavik Anil Patel
Electrodes made using a mixture of carbon allotropes has been an effective approach to enhance conductivity. Often such electrodes are made as composites or through layer-by-layer construction. These are time-consuming approaches; however, recently fused filament fabrication (FFF) 3D printing has shown significant potential in rapid manufacturing of conductive materials. To make mixed materials using 3D printing, in-house fabrication of printable filaments has shown significant promise. However, this requires specialised equipment, limiting accessibility. Our study explored the potential of creative electrode design and dual nozzle printing to make carbon thermoplastic mixed material electrodes. We created mixed materials electrodes in a helix design where internal pathways would rotate by 180º. The conductivity, capacitance and charge transfer resistance were monitored. We showed that making mixed materials with various permutations of carbon black, multi-wall carbon nanotubes and graphene outperformed single carbon allotrope materials for conductivity. The helix design provided the scope for making mixed material, as when the degree of rotation was reduced, the conductivity decreased. Our findings highlight that a combination of the helix architecture design and mixing achieved on the boundaries of the two materials from the dual nozzle printing process can generate a simple and accessible strategy for making carbon thermoplastic mixed materials, which can have significant impact in sensing applications and generation of energy storage devices.
{"title":"Architectural design and dual nozzle 3D printing creates carbon thermoplastic multi-materials with enhanced conductivity","authors":"Ricoveer Shergill , Oliver Keattch , Bhavik Anil Patel","doi":"10.1016/j.electacta.2025.145924","DOIUrl":"10.1016/j.electacta.2025.145924","url":null,"abstract":"<div><div>Electrodes made using a mixture of carbon allotropes has been an effective approach to enhance conductivity. Often such electrodes are made as composites or through layer-by-layer construction. These are time-consuming approaches; however, recently fused filament fabrication (FFF) 3D printing has shown significant potential in rapid manufacturing of conductive materials. To make mixed materials using 3D printing, in-house fabrication of printable filaments has shown significant promise. However, this requires specialised equipment, limiting accessibility. Our study explored the potential of creative electrode design and dual nozzle printing to make carbon thermoplastic mixed material electrodes. We created mixed materials electrodes in a helix design where internal pathways would rotate by 180º. The conductivity, capacitance and charge transfer resistance were monitored. We showed that making mixed materials with various permutations of carbon black, multi-wall carbon nanotubes and graphene outperformed single carbon allotrope materials for conductivity. The helix design provided the scope for making mixed material, as when the degree of rotation was reduced, the conductivity decreased. Our findings highlight that a combination of the helix architecture design and mixing achieved on the boundaries of the two materials from the dual nozzle printing process can generate a simple and accessible strategy for making carbon thermoplastic mixed materials, which can have significant impact in sensing applications and generation of energy storage devices.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145924"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145936
Yabo Li , Lili Wang , Emayavaramban Indubala , Chao Ma , Chun Li , Luming Xiao , Bo Lv , Shanshan Yao
Lithium sulfur batteries face several challenges, including significant volumetric expansion during cycling, slow kinetics of sulfur redox reactions, and the shuttle effect of solubility lithium polysulfides. Polar metal oxides, due to their hydrophilic surface, can effectively adsorb polysulfides, facilitating their confinement and reducing their mobility, which helps to mitigate the shuttle effect. In this study, CuO nanoparticles embedded within porous nitrogen-doped porous carbon (CuO@NC) composite with a high specific surface area of 865.68 m2 g-1 are successfully synthesized without use of additional template. The CuO@NC composite enables the synergy between the physical adsorption provided by the porous carbon framework and the chemical adsorption-catalysis of CuO, thereby enhancing polysulfide immobilization and improving electrochemical performance. Cells fabricated with CuO@NC modified separator show a high specific capacity of 969.8 mAh g-1 at 0.5 C, excellent rate capability (937.9 mAh g-1 at 1 C), and a stable capacity of 793.2 mAh g-1 after 200 cycles with a low decay rate of 0.09 % per cycle. Furthermore, the CuO@NC modified separator maintains a discharge capacity of 725.6 mAh g-1 at -10 °C. Even with sulfur loading up to 5.6 mg cm-2, it can still exhibit remarkable cycling stability. This study demonstrates the design of metal oxides-decorated porous heteroatoms doped carbon materials as an effective strategy for fabricating highly functional separator that inhibit the polysulfides shuttle effect.
{"title":"Highly dispersed CuO nanoparticles embedded within porous nitrogen doped carbon as effective electrocatalyst for lithium sulfur batteries","authors":"Yabo Li , Lili Wang , Emayavaramban Indubala , Chao Ma , Chun Li , Luming Xiao , Bo Lv , Shanshan Yao","doi":"10.1016/j.electacta.2025.145936","DOIUrl":"10.1016/j.electacta.2025.145936","url":null,"abstract":"<div><div>Lithium sulfur batteries face several challenges, including significant volumetric expansion during cycling, slow kinetics of sulfur redox reactions, and the shuttle effect of solubility lithium polysulfides. Polar metal oxides, due to their hydrophilic surface, can effectively adsorb polysulfides, facilitating their confinement and reducing their mobility, which helps to mitigate the shuttle effect. In this study, CuO nanoparticles embedded within porous nitrogen-doped porous carbon (CuO@NC) composite with a high specific surface area of 865.68 m<sup>2</sup> g<sup>-1</sup> are successfully synthesized without use of additional template. The CuO@NC composite enables the synergy between the physical adsorption provided by the porous carbon framework and the chemical adsorption-catalysis of CuO, thereby enhancing polysulfide immobilization and improving electrochemical performance. Cells fabricated with CuO@NC modified separator show a high specific capacity of 969.8 mAh g<sup>-1</sup> at 0.5 C, excellent rate capability (937.9 mAh g<sup>-1</sup> at 1 C), and a stable capacity of 793.2 mAh g<sup>-1</sup> after 200 cycles with a low decay rate of 0.09 % per cycle. Furthermore, the CuO@NC modified separator maintains a discharge capacity of 725.6 mAh g<sup>-1</sup> at -10 °C. Even with sulfur loading up to 5.6 mg cm<sup>-2</sup>, it can still exhibit remarkable cycling stability. This study demonstrates the design of metal oxides-decorated porous heteroatoms doped carbon materials as an effective strategy for fabricating highly functional separator that inhibit the polysulfides shuttle effect.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145936"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145921
Pei-En Lo, Chia-Chen Li
The poor conductivity of sulfur electrodes in lithium-sulfur batteries (LSBs) has led to interest in using three-dimensional conductive carbon fabric (Cf) as the sulfur cathode host. This study examines how two types of Cfs with distinct porous architectures influence LSB performance. A three-electrode technique is used to separate the cathode and anode contributions to the battery impedances and distribution of relaxation times (DRT). This method helps assess how the architecture of Cf affects the electrochemical behavior of sulfur cathodes and determines which electrode has the greatest impact on overall battery performance. Our findings show that battery impedance mostly originates from the cathode, particularly when fully discharged. Variations in Cf architecture mainly affect charge transfer resistance, as confirmed by both impedance and DRT analyses. In cycling tests, the Cf that has a higher conductivity slows impedance rise and an improved capacity retention. Potentiostatic intermittent titration technique tests indicate that these effects are not solely due to improved conductivity but also to Cf architecture's influence on polysulfide conversion kinetics. Notably, the battery failure is attributed to lithium dendrite growth on the anode, with significant increases in the solid electrolyte interphase resistance and the electrical double-layer impedance of the cathode observed before short-circuiting.
{"title":"Separation of cathode and anode impedances for analyzing polysulfide conversion in Li-S batteries with a hierarchical porous carbon host","authors":"Pei-En Lo, Chia-Chen Li","doi":"10.1016/j.electacta.2025.145921","DOIUrl":"10.1016/j.electacta.2025.145921","url":null,"abstract":"<div><div>The poor conductivity of sulfur electrodes in lithium-sulfur batteries (LSBs) has led to interest in using three-dimensional conductive carbon fabric (Cf) as the sulfur cathode host. This study examines how two types of Cfs with distinct porous architectures influence LSB performance. A three-electrode technique is used to separate the cathode and anode contributions to the battery impedances and distribution of relaxation times (DRT). This method helps assess how the architecture of Cf affects the electrochemical behavior of sulfur cathodes and determines which electrode has the greatest impact on overall battery performance. Our findings show that battery impedance mostly originates from the cathode, particularly when fully discharged. Variations in Cf architecture mainly affect charge transfer resistance, as confirmed by both impedance and DRT analyses. In cycling tests, the Cf that has a higher conductivity slows impedance rise and an improved capacity retention. Potentiostatic intermittent titration technique tests indicate that these effects are not solely due to improved conductivity but also to Cf architecture's influence on polysulfide conversion kinetics. Notably, the battery failure is attributed to lithium dendrite growth on the anode, with significant increases in the solid electrolyte interphase resistance and the electrical double-layer impedance of the cathode observed before short-circuiting.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145921"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145914
Li Li , Jiajing Peng , Zimin Li , Wanqing You , Jing Li , Yichen Bao , Bright O. Okonkwo , Yimian Chen , Jianqiu Wang
Metal cations, commonly present in industrial cooling water, was found to have certain effect on the corrosion inhibition of copper by tolyltriazole (TTA). Based on the investigation through electrochemistry, immersion test and in-depth analysis, Ca2+, Zn2+ and Mg2+ all show synergistic effect with TTA, with synergistic factor ranging from 1.76 to 15.1. Zn2+ was found to incorporate homogeneously onto the surface, while Ca2+ and Mg2+ precipitate locally and show better resistance to pitting. In summary, the presence of such metal cations in industrial cooling water is rather positive than a concern from the corrosion inhibition perspective.
{"title":"Synergistic inhibition effect of metal cations and tolyltriazole on copper in industrial cooling system","authors":"Li Li , Jiajing Peng , Zimin Li , Wanqing You , Jing Li , Yichen Bao , Bright O. Okonkwo , Yimian Chen , Jianqiu Wang","doi":"10.1016/j.electacta.2025.145914","DOIUrl":"10.1016/j.electacta.2025.145914","url":null,"abstract":"<div><div>Metal cations, commonly present in industrial cooling water, was found to have certain effect on the corrosion inhibition of copper by tolyltriazole (TTA). Based on the investigation through electrochemistry, immersion test and in-depth analysis, Ca<sup>2+</sup>, Zn<sup>2+</sup> and Mg<sup>2+</sup> all show synergistic effect with TTA, with synergistic factor ranging from 1.76 to 15.1. Zn<sup>2+</sup> was found to incorporate homogeneously onto the surface, while Ca<sup>2+</sup> and Mg<sup>2+</sup> precipitate locally and show better resistance to pitting. In summary, the presence of such metal cations in industrial cooling water is rather positive than a concern from the corrosion inhibition perspective.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"522 ","pages":"Article 145914"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145920
Shamshad Ali , Jicheng Jiang , Can Guo , Donghuang Wang , Xin Wang , Weiwei Xia , Maosen Fu , Zaifang Yuan , Wenchao Yan , Jingze Li , Yongqi Zhang , Aijun Zhou
This paper investigates the hydrated and dehydrated phases of cubic and monoclinic Na2Mn[Fe(CN)6], focusing on the impact of crystal water on their electrochemical, structural, and volumetric properties. Interstitial and coordination water impact these materials differently. Removing water increases the coulombic attraction between Na+ and N−, reducing ∠Mn-N-C and ∠Fe-C-N angles and decreasing volume. The densification effect is more pronounced in the monoclinic sample due to its higher sodium content. The dehydrated cubic sample (PW-DH-C) has better cycling stability than the monoclinic sample (PW-DH-MC). The reduced cycling stability in PW-DH-MC is due to its denser rhombohedral structure, resulting from its higher sodium content, which affects the ∠Mn-N-C and ∠Fe-C-N angles. Dehydration triggers Jahn-Teller distortion in Mn3+ ions, inducing reversible rhombohedral-to-tetragonal phase transitions during cycling. After 200 cycles, the capacity retention of the dehydrated cubic sample improves to 59 % when exposed to air and reabsorbing moisture, compared to 50 % in its dehydrated state. Similarly, the dehydrated monoclinic sample shows an increase in retention to 28 %, up from 20 % in its dry condition. Additionally, PW-DH-C experiences lower volumetric changes during cycling, attributed to fewer sodium ions and more Fe(CN)64− vacancies. These findings highlight water's crucial role in optimizing Na2Mn[Fe(CN)6] performance for practical applications.
{"title":"The role of crystal water in the electrochemical properties of sodium manganese hexacyanoferrate cathodes in sodium-ion batteries","authors":"Shamshad Ali , Jicheng Jiang , Can Guo , Donghuang Wang , Xin Wang , Weiwei Xia , Maosen Fu , Zaifang Yuan , Wenchao Yan , Jingze Li , Yongqi Zhang , Aijun Zhou","doi":"10.1016/j.electacta.2025.145920","DOIUrl":"10.1016/j.electacta.2025.145920","url":null,"abstract":"<div><div>This paper investigates the hydrated and dehydrated phases of cubic and monoclinic Na<sub>2</sub>Mn[Fe(CN)<sub>6</sub>], focusing on the impact of crystal water on their electrochemical, structural, and volumetric properties. Interstitial and coordination water impact these materials differently. Removing water increases the coulombic attraction between Na<sup>+</sup> and N<sup>−</sup>, reducing ∠Mn-N-C and ∠Fe-C-N angles and decreasing volume. The densification effect is more pronounced in the monoclinic sample due to its higher sodium content. The dehydrated cubic sample (PW-DH-C) has better cycling stability than the monoclinic sample (PW-DH-MC). The reduced cycling stability in PW-DH-MC is due to its denser rhombohedral structure, resulting from its higher sodium content, which affects the ∠Mn-N-C and ∠Fe-C-N angles. Dehydration triggers Jahn-Teller distortion in Mn<sup>3+</sup> ions, inducing reversible rhombohedral-to-tetragonal phase transitions during cycling. After 200 cycles, the capacity retention of the dehydrated cubic sample improves to 59 % when exposed to air and reabsorbing moisture, compared to 50 % in its dehydrated state. Similarly, the dehydrated monoclinic sample shows an increase in retention to 28 %, up from 20 % in its dry condition. Additionally, PW-DH-C experiences lower volumetric changes during cycling, attributed to fewer sodium ions and more Fe(CN)<sub>6</sub><sup>4−</sup> vacancies. These findings highlight water's crucial role in optimizing Na<sub>2</sub>Mn[Fe(CN)<sub>6</sub>] performance for practical applications.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145920"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145927
Roshan Nazir
Electrocatalytic nitrogen reduction (ENRR) is a green and versatile approach to reduce atmospheric nitrogen into ammonia. This promising approach however lacks inexpensive and efficient electrocatalyst that promotes scalable ammonia production. Herein, we present a non-precious, mesoporous NiFe2O4 nanosheets (m-NiFe2O4 NS) prepared via a simple solution combustion method for the ENRR. The synthesized m-NiFe2O4 NS showed an outstanding NH3 yield of 45 μgh−1mgcat-1, TOF of 0.618h-1, and Faradaic efficiency of 12 % at a potential of -0.4 V vs. RHE. This activity of m-NiFe2O4 NS is attributed to highly porous structure, and the presence of Fe and Ni atoms, where Fe atoms active sites promotes N2 activation, polarization, and boosts ENRR activity and Ni atoms protects ENRR active sites on Fe for competing HER and makes them exclusively available for ENRR. In this work, we proposed enzymatic pathway mechanism based on in-situ Raman investigations. That revealed the formation of *N2H and *N2H2 type intermediates during ammonia formation. The preliminary step is N2 adsorption on the active sites (metal centres and surface defects) of m-NiFe2O4NS followed by proton coupled electron transfer reactions (PCET) that generates*N2H and *N2H2 type intermediates which then undergoes series of PCETs to generate NH3.
{"title":"Fe dominated and O-vac rich mesoporous NiFe2O4 for enhanced electrocatalytic Nitrogen reduction to ammonia through enzymatic pathway","authors":"Roshan Nazir","doi":"10.1016/j.electacta.2025.145927","DOIUrl":"10.1016/j.electacta.2025.145927","url":null,"abstract":"<div><div>Electrocatalytic nitrogen reduction (ENRR) is a green and versatile approach to reduce atmospheric nitrogen into ammonia. This promising approach however lacks inexpensive and efficient electrocatalyst that promotes scalable ammonia production. Herein, we present a non-precious, mesoporous NiFe<sub>2</sub>O<sub>4</sub> nanosheets (m-NiFe<sub>2</sub>O<sub>4</sub> NS) prepared via a simple solution combustion method for the ENRR. The synthesized m-NiFe<sub>2</sub>O<sub>4</sub> NS showed an outstanding NH<sub>3</sub> yield of 45 μgh<sup>−1</sup>mg<sub>cat</sub><sup>-1</sup>, TOF of 0.618h<sup>-1</sup>, and Faradaic efficiency of 12 % at a potential of -0.4 V vs. RHE. This activity of m-NiFe<sub>2</sub>O<sub>4</sub> NS is attributed to highly porous structure, and the presence of Fe and Ni atoms, where Fe atoms active sites promotes N<sub>2</sub> activation, polarization, and boosts ENRR activity and Ni atoms protects ENRR active sites on Fe for competing HER and makes them exclusively available for ENRR. In this work, we proposed enzymatic pathway mechanism based on in-situ Raman investigations. That revealed the formation of *N<sub>2</sub>H and *N<sub>2</sub>H<sub>2</sub> type intermediates during ammonia formation. The preliminary step is N<sub>2</sub> adsorption on the active sites (metal centres and surface defects) of m-NiFe<sub>2</sub>O<sub>4</sub>NS followed by proton coupled electron transfer reactions (PCET) that generates*N<sub>2</sub>H and *N<sub>2</sub>H<sub>2</sub> type intermediates which then undergoes series of PCETs to generate NH<sub>3</sub>.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145927"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oxygen reduction is the critical step in advanced chlor-alkali electrolysis, which has motivated extensive research in catalyst development for improved efficiency and durability. This study investigates the oxygen reduction reaction (ORR) on Cu-based electrocatalysts supported on N-doped carbon (Cu/NC), derived from a Cu-modified zeolitic imidazolate framework (ZIF), and their ultimate performance in a chlor-alkali electrolyzer. Through comprehensive electrochemical characterization in 0.1 M NaOH solution, values of Eonset = 0.87 V and E1/2 = 0.75 V (vs. RHE) were obtained, which are competitive with commercial Pt/C despite the superior j achieved by the latter in LSV tests. The electron transfer number (n) of the optimum Cu/NC was 4, very close to benchmark catalyst Pt/C 20 wt. % (n = 3.94). Cu/NC had a low Tafel slope (128 mV dec−1), thus speeding up the ORR on this nanocatalyst. Additionally, chronoamperometry and accelerated durability tests demonstrated the long-term stability of Cu/NC for 10 h. The catalyst was assembled as an oxygen depolarized cathode (ODC) in a purpose-designed advanced chlor-alkali electrolyzer, resulting in a cell voltage of 2.1 V at 1 kA m-2 and 80 °C, which underscores the potential of Cu-based nanocatalysts in electrochemical energy devices. This research serves to leverage insights for the use of advanced electrocatalysts to enhance the efficiency and sustainability of chlor-alkali electrolysis.
{"title":"Integration of a non-precious pyrolyzed Cu-doped ZIF as an oxygen depolarized cathode in an advanced chlor-alkali electrolyzer","authors":"Tahereh Jangjooye Shaldehi , Lele Zhao , Teresa Andreu , Soosan Rowshanzamir , Ignasi Sirés","doi":"10.1016/j.electacta.2025.145929","DOIUrl":"10.1016/j.electacta.2025.145929","url":null,"abstract":"<div><div>Oxygen reduction is the critical step in advanced chlor-alkali electrolysis, which has motivated extensive research in catalyst development for improved efficiency and durability. This study investigates the oxygen reduction reaction (ORR) on Cu-based electrocatalysts supported on N-doped carbon (Cu/NC), derived from a Cu-modified zeolitic imidazolate framework (ZIF), and their ultimate performance in a chlor-alkali electrolyzer. Through comprehensive electrochemical characterization in 0.1 M NaOH solution, values of <em>E</em><sub>onset</sub> = 0.87 V and <em>E</em><sub>1/</sub><sub>2</sub> = 0.75 V (<em>vs.</em> RHE) were obtained, which are competitive with commercial Pt/C despite the superior <em>j</em> achieved by the latter in LSV tests. The electron transfer number (<em>n</em>) of the optimum Cu/NC was 4, very close to benchmark catalyst Pt/C 20 wt. % (<em>n</em> = 3.94). Cu/NC had a low Tafel slope (128 mV dec<sup>−1</sup>), thus speeding up the ORR on this nanocatalyst. Additionally, chronoamperometry and accelerated durability tests demonstrated the long-term stability of Cu/NC for 10 h. The catalyst was assembled as an oxygen depolarized cathode (ODC) in a purpose-designed advanced chlor-alkali electrolyzer, resulting in a cell voltage of 2.1 V at 1 kA m<sup>-2</sup> and 80 °C, which underscores the potential of Cu-based nanocatalysts in electrochemical energy devices. This research serves to leverage insights for the use of advanced electrocatalysts to enhance the efficiency and sustainability of chlor-alkali electrolysis.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"522 ","pages":"Article 145929"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145928
Zeferino S.B. Pedro, Joseany M.S. Almeida, Christopher M.A. Brett
Polymer films were formed from a triarylmethane redox dye, brilliant green (BG) by electropolymerization on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (MWCNT) using potential cycling in glyceline deep eutectic solvent, formed by choline chloride (ChCl), and glycerol (G) 1:2 molar ratio with 5 % added water, with addition of different acid dopants. Electropolymerization was also carried out on unmodified GCE for comparison. The modified electrode, PBG/MWCNT/GCE, was characterized by cyclic voltammetry in 0.1 M Britton-Robinson buffer at pH 3, electrochemical impedance spectroscopy and the morphology of its surface by scanning electron microscopy. The best electrochemical behaviour was obtained with a polymerization scan rate of 100 mV s−1. The polymer modified electrode was used for the determination of epinephrine using differential pulse voltammetry. The linear range was 5 µM to 50 µM with a detection limit of 0.7 µM. The sensor was tested on pharmaceutical and urine samples successfully with good reproducibility and repeatability.
{"title":"Influence of deep eutectic solvent and water mixtures on the electropolymerization of brilliant green on nanotube modified electrodes for the electrochemical determination of epinephrine","authors":"Zeferino S.B. Pedro, Joseany M.S. Almeida, Christopher M.A. Brett","doi":"10.1016/j.electacta.2025.145928","DOIUrl":"10.1016/j.electacta.2025.145928","url":null,"abstract":"<div><div>Polymer films were formed from a triarylmethane redox dye, brilliant green (BG) by electropolymerization on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (MWCNT) using potential cycling in glyceline deep eutectic solvent, formed by choline chloride (ChCl), and glycerol (G) 1:2 molar ratio with 5 % added water, with addition of different acid dopants. Electropolymerization was also carried out on unmodified GCE for comparison. The modified electrode, PBG/MWCNT/GCE, was characterized by cyclic voltammetry in 0.1 M Britton-Robinson buffer at pH 3, electrochemical impedance spectroscopy and the morphology of its surface by scanning electron microscopy. The best electrochemical behaviour was obtained with a polymerization scan rate of 100 mV s<sup>−1</sup>. The polymer modified electrode was used for the determination of epinephrine using differential pulse voltammetry. The linear range was 5 µM to 50 µM with a detection limit of 0.7 µM. The sensor was tested on pharmaceutical and urine samples successfully with good reproducibility and repeatability.</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145928"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.electacta.2025.145935
Guanhua Yang , Jie Zhang , Zhiguo Zhang , Xianling Qin , Quansheng Teng , Huwei Hao , Zhiqing Zhang , Xueyou Tan , Qingyu Li , Hongqiang Wang
Hard carbon materials synthesized from biomass precursors exhibit the excellent characteristics of high capacity, cost-effectiveness and wide-ranging availability. In this study, the aniline-functionalized hard carbon material (HC-P-F) with porous spherical morphology was prepared successfully by enzymatic hydrolysis combing with “burying” heat treatment and diazotization reaction using taro starch as carbon source. The HC-P-F possesses porous morphology, which can shorten the ion transport path, thereby increasing the ion transport rate, and also providing more active sites for Na+ storage. At the same time, the aniline radical grafting on the surface of the hard carbon materials helps to improve the battery life and cycle stability. The porous spherical structure and surface functionalization produce a good synergistic effect, increasing the specific surface area, enhancing the stability of the cycle, improving the electrical conductivity and promoting the rapid insertion and removal of ions of the hard carbon material. The results show that the HC-P-F maintains a high reversible specific capacity of 260.19 mAh g-1 after 300 cycles at 0.5 A g-1. And it displays excellent rate performance with an average reversible specific capacity of 358.5, 338.39, 308.32, 276.86, 231.61 and 120.46 mAh g-1 at 0.1, 0.2, 0.5, 1, 2 and 5 A g-1, respectively. Furthermore, the HC-P-F exhibits lower impedance, significant capacitive behavior dominated by pseudocapacitance contribution and faster sodium ion interface dynamics comparing with other hard carbon materials. In addition, when assembled into full cell with commercial sodium vanadate (NVP), it demonstrates exceptional cycling stability with a high energy density of 184.06 Wh kg-1 after 300 cycles at 0.5 A g-1. This successful preparation of the aniline-functionalized hard carbon materials provides another solution for improving the electrochemical properties of the anode electrode materials, which would promote the application research of starch-based hard carbon anode materials in sodium ion batteries (SIBs).
{"title":"Surface functionalized porous spherical hard carbon material derived from taro starch for high performance sodium storage","authors":"Guanhua Yang , Jie Zhang , Zhiguo Zhang , Xianling Qin , Quansheng Teng , Huwei Hao , Zhiqing Zhang , Xueyou Tan , Qingyu Li , Hongqiang Wang","doi":"10.1016/j.electacta.2025.145935","DOIUrl":"10.1016/j.electacta.2025.145935","url":null,"abstract":"<div><div>Hard carbon materials synthesized from biomass precursors exhibit the excellent characteristics of high capacity, cost-effectiveness and wide-ranging availability. In this study, the aniline-functionalized hard carbon material (HC-P-F) with porous spherical morphology was prepared successfully by enzymatic hydrolysis combing with “burying” heat treatment and diazotization reaction using taro starch as carbon source. The HC-P-F possesses porous morphology, which can shorten the ion transport path, thereby increasing the ion transport rate, and also providing more active sites for Na<sup>+</sup> storage. At the same time, the aniline radical grafting on the surface of the hard carbon materials helps to improve the battery life and cycle stability. The porous spherical structure and surface functionalization produce a good synergistic effect, increasing the specific surface area, enhancing the stability of the cycle, improving the electrical conductivity and promoting the rapid insertion and removal of ions of the hard carbon material. The results show that the HC-P-F maintains a high reversible specific capacity of 260.19 mAh g<sup>-1</sup> after 300 cycles at 0.5 A g<sup>-1</sup>. And it displays excellent rate performance with an average reversible specific capacity of 358.5, 338.39, 308.32, 276.86, 231.61 and 120.46 mAh g<sup>-1</sup> at 0.1, 0.2, 0.5, 1, 2 and 5 A g<sup>-1</sup>, respectively. Furthermore, the HC-P-F exhibits lower impedance, significant capacitive behavior dominated by pseudocapacitance contribution and faster sodium ion interface dynamics comparing with other hard carbon materials. In addition, when assembled into full cell with commercial sodium vanadate (NVP), it demonstrates exceptional cycling stability with a high energy density of 184.06 Wh kg<sup>-1</sup> after 300 cycles at 0.5 A g<sup>-1</sup>. This successful preparation of the aniline-functionalized hard carbon materials provides another solution for improving the electrochemical properties of the anode electrode materials, which would promote the application research of starch-based hard carbon anode materials in sodium ion batteries (SIBs).</div></div>","PeriodicalId":305,"journal":{"name":"Electrochimica Acta","volume":"521 ","pages":"Article 145935"},"PeriodicalIF":5.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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