Pub Date : 2024-05-21DOI: 10.1149/2754-2734/ad4e48
Rishivandhiga Jayakumar, V. Shipitsyn, Chanmonirath (Michael) Chak, Wenhua Zuo, Bing Sun, Xiaochuan Lu, Lin Ma
Traditional linear carbonates including dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) were investigated as co-solvents for the dimethyl-2,5-dioxahexane carboxylate (DMOHC)-based electrolyte in Na0.97Ca0.03[Mn0.39Fe0.31Ni0.22Zn0.08]O2 (NCMFNZO)/hard carbon (HC) pouch cells. The EMC-containing cell displays excellent electrochemical performance, exhibiting only a 1.6 mAh irreversible capacity loss during 500 hours of storage at 4V and 40°C, and maintaining over 80% capacity retention after 200 cycles up to 4V at 40°C. Severe gas evolution and Na plating issues are present in all the tested systems.
{"title":"Communication — The Impact of Co-solvent Selection for Dimethyl-2,5-dioxahexane carboxylate in Sodium Ion Batteries","authors":"Rishivandhiga Jayakumar, V. Shipitsyn, Chanmonirath (Michael) Chak, Wenhua Zuo, Bing Sun, Xiaochuan Lu, Lin Ma","doi":"10.1149/2754-2734/ad4e48","DOIUrl":"https://doi.org/10.1149/2754-2734/ad4e48","url":null,"abstract":"\u0000 Traditional linear carbonates including dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) were investigated as co-solvents for the dimethyl-2,5-dioxahexane carboxylate (DMOHC)-based electrolyte in Na0.97Ca0.03[Mn0.39Fe0.31Ni0.22Zn0.08]O2 (NCMFNZO)/hard carbon (HC) pouch cells. The EMC-containing cell displays excellent electrochemical performance, exhibiting only a 1.6 mAh irreversible capacity loss during 500 hours of storage at 4V and 40°C, and maintaining over 80% capacity retention after 200 cycles up to 4V at 40°C. Severe gas evolution and Na plating issues are present in all the tested systems.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"121 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1149/2754-2734/ad41ed
Madhurima Barman, S. Kobi, Arindam Sarkar
We report here the feasibility of using LaTMO3-based perovskites (TM = Co, Cr, Fe, Mn, Ni, i.e., non-Cu 3d transition metals) as electrocatalysts for electrochemical CO2 reduction reaction (eCO2RR). Phase pure LaTMO3s, having TM-ions in multiple oxidation states for all and O-defects for LaFeO3 and LaNiO3, have been synthesized and tested as electrocatalysts for eCO2RR in fuel cell type set-up. The above characteristics of the La-TM-oxides have been found to influence the current densities during eCO2RR at the various applied potentials, with favorable effects of the presence of O-defects (as for LaFeO3 and LaNiO3). Upon eCO2RR, both C1 and C2 liquid products have been obtained, including ethanol, with a partial current density of -2.66 mA/cm2 at -1.2 V vs. RHE (for LaFeO3). The types of products and the faradic efficiencies have been found to depend on the TM-ion present (in the LaTMO3); in particular, the oxidation state(s), associated O-defect(s) and electronic conductivity. Furthermore, the electrocatalysts have been found to be stable during eCO2RR. Overall, the present work highlights the potential of La-TM-oxide perovskites for usage as stable electrocatalysts for eCO2RR, and also provides insights into the proper selection of ‘TM’ and reaction conditions for obtaining the desired product(s).
{"title":"La-based Transition Metal Oxide Perovskites as Electrocatalysts for Electrochemical Carbon Dioxide Reduction","authors":"Madhurima Barman, S. Kobi, Arindam Sarkar","doi":"10.1149/2754-2734/ad41ed","DOIUrl":"https://doi.org/10.1149/2754-2734/ad41ed","url":null,"abstract":"\u0000 We report here the feasibility of using LaTMO3-based perovskites (TM = Co, Cr, Fe, Mn, Ni, i.e., non-Cu 3d transition metals) as electrocatalysts for electrochemical CO2 reduction reaction (eCO2RR). Phase pure LaTMO3s, having TM-ions in multiple oxidation states for all and O-defects for LaFeO3 and LaNiO3, have been synthesized and tested as electrocatalysts for eCO2RR in fuel cell type set-up. The above characteristics of the La-TM-oxides have been found to influence the current densities during eCO2RR at the various applied potentials, with favorable effects of the presence of O-defects (as for LaFeO3 and LaNiO3). Upon eCO2RR, both C1 and C2 liquid products have been obtained, including ethanol, with a partial current density of -2.66 mA/cm2 at -1.2 V vs. RHE (for LaFeO3). The types of products and the faradic efficiencies have been found to depend on the TM-ion present (in the LaTMO3); in particular, the oxidation state(s), associated O-defect(s) and electronic conductivity. Furthermore, the electrocatalysts have been found to be stable during eCO2RR. Overall, the present work highlights the potential of La-TM-oxide perovskites for usage as stable electrocatalysts for eCO2RR, and also provides insights into the proper selection of ‘TM’ and reaction conditions for obtaining the desired product(s).","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"57 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140666676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1149/2754-2734/ad3f31
Yelizaveta A. Morkhova, Mariia Koroleva, Anastasia V Egorova, Aleksei Krasnov, Inna Starostina, Artem Kabanov
The CaNb2O6 and ZnNb2O6 columbites (Sp.gr. Pbcn) were studied as oxygen ion conductors both theoretically and experimentally. A theoretical approach included geometrical-topological analysis, bond valence site energy (BVSE) and density functional theory (DFT) calculations. The BVSE approach showed the possibility of pure oxygen ions diffusion with migration energies less than 0.45 eV in both compounds. However, DFT calculations indicated the possibility of diffusion of both anions and cations. The single-phases columbites were synthesized by the Pechini method for accurately determine charge carriers type and investigated by impedance spectroscopy, by the Tubandt method, which confirmed the absence of cationic conductivity, and measured the electrical conductivity as a function of oxygen partial pressures. The CaNb2O6 sample had the pure oxygen-ionic conductivity ∼2×10-6 S cm–1 at 800 °C (Ea = 0.82 eV), while the ZnNb2O6 had a similar conductivity value due to mixed ionic-electronic contribution (Ea = 0.83 eV). The electromotive force method also showed the predominance of the ionic type of conductivity in CaNb2O6, while ZnNb2O6 has a mixed conductivity with ion transport number of about 0.4. Additionally, we synthesized Ti-doped samples MNb2-xTixO6-0.5x (M = Mg, Ca; x = 0.1, 0.2) to study the doping effect on conducting properties.
{"title":"Exhaustive Study of Electrical Conductivity in the MNb2-xTixO6-0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites","authors":"Yelizaveta A. Morkhova, Mariia Koroleva, Anastasia V Egorova, Aleksei Krasnov, Inna Starostina, Artem Kabanov","doi":"10.1149/2754-2734/ad3f31","DOIUrl":"https://doi.org/10.1149/2754-2734/ad3f31","url":null,"abstract":"\u0000 The CaNb2O6 and ZnNb2O6 columbites (Sp.gr. Pbcn) were studied as oxygen ion conductors both theoretically and experimentally. A theoretical approach included geometrical-topological analysis, bond valence site energy (BVSE) and density functional theory (DFT) calculations. The BVSE approach showed the possibility of pure oxygen ions diffusion with migration energies less than 0.45 eV in both compounds. However, DFT calculations indicated the possibility of diffusion of both anions and cations. The single-phases columbites were synthesized by the Pechini method for accurately determine charge carriers type and investigated by impedance spectroscopy, by the Tubandt method, which confirmed the absence of cationic conductivity, and measured the electrical conductivity as a function of oxygen partial pressures. The CaNb2O6 sample had the pure oxygen-ionic conductivity ∼2×10-6 S cm–1 at 800 °C (Ea = 0.82 eV), while the ZnNb2O6 had a similar conductivity value due to mixed ionic-electronic contribution (Ea = 0.83 eV). The electromotive force method also showed the predominance of the ionic type of conductivity in CaNb2O6, while ZnNb2O6 has a mixed conductivity with ion transport number of about 0.4. Additionally, we synthesized Ti-doped samples MNb2-xTixO6-0.5x (M = Mg, Ca; x = 0.1, 0.2) to study the doping effect on conducting properties.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"32 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140696734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1149/2754-2734/ad3cf4
A.A. Kulikovsky
Recently, it was shown that performance of the cathode catalyst layer in a PEM fuel cell dramatically improves if the oxygen concentration (OC) at the catalyst/gas diffusion layer (GDL) interface oscillates in--phase with the overpotential. However, OC oscillations could only be organized in the cathode channel. Does transport through the GDL affect the phase angle of OC oscillations? Below, it is shown that at frequencies below 1 Hz, the GDL does not change this phase angle. At high frequencies, the phase angle after transport through the GDL is $-3pi/4$ regardless of the GDL transport parameters.
{"title":"Oscillating Oxygen Concentration Transport through PEM Fuel Cell Gas Diffusion Layer: Variation of the Phase Angle","authors":"A.A. Kulikovsky","doi":"10.1149/2754-2734/ad3cf4","DOIUrl":"https://doi.org/10.1149/2754-2734/ad3cf4","url":null,"abstract":"\u0000 Recently, it was shown that performance of the cathode catalyst layer in a PEM fuel cell dramatically improves if the oxygen concentration (OC) at the catalyst/gas diffusion layer (GDL) interface oscillates in--phase with the overpotential. However, OC oscillations could only be organized in the cathode channel. Does transport through the GDL affect the phase angle of OC oscillations? Below, it is shown that at frequencies below 1 Hz, the GDL does not change this phase angle. At high frequencies, the phase angle after transport through the GDL is $-3pi/4$ regardless of the GDL transport parameters.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140717677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-04DOI: 10.1149/2754-2734/ad3a7c
O. Medlinsky, Constantinos Hadjistassou, Amir Eliezer
Offshore facilities, such as oil and gas rigs, wind turbines, and related subsea equipment, typically use flanges fastened using bolts and nuts as the main connectors. In this study, multidisciplinary parameters, namely the preload torque used to tighten bolts, simulated subsea water currents, water temperature, and impressed current cathodic protection, were applied to ASTM A193 B7 bolts. An experimental supervisory control and data acquisition system was designed to obtain measurements every 5 min throughout a 21-day experiment. Finite element analysis was performed to predict the structurally vulnerable areas of the bolts. A strong correlation was found between the reference electrode readings and the measured electrical current, tightening torque, and water temperature. As the water temperature rises during the day, the reference electrode reading becomes less negative and the electrical current decreases. Subsea water currents cause about a four-time increase in the bolt corrosion rate, with unprotected bolts suffering a nine-time-higher corrosion rate than protected bolts. A unique supply–demand interaction is observed; less protection is supplied to areas with lower corrosion rates (lower demand for protection). Finally, scanning electron microscopy examination reveals new insights into the failure mechanisms of subsea bolts.
{"title":"Shedding Light on the Failure Factors of Subsea Critical Fastener Bolts","authors":"O. Medlinsky, Constantinos Hadjistassou, Amir Eliezer","doi":"10.1149/2754-2734/ad3a7c","DOIUrl":"https://doi.org/10.1149/2754-2734/ad3a7c","url":null,"abstract":"\u0000 Offshore facilities, such as oil and gas rigs, wind turbines, and related subsea equipment, typically use flanges fastened using bolts and nuts as the main connectors. In this study, multidisciplinary parameters, namely the preload torque used to tighten bolts, simulated subsea water currents, water temperature, and impressed current cathodic protection, were applied to ASTM A193 B7 bolts. An experimental supervisory control and data acquisition system was designed to obtain measurements every 5 min throughout a 21-day experiment. Finite element analysis was performed to predict the structurally vulnerable areas of the bolts. A strong correlation was found between the reference electrode readings and the measured electrical current, tightening torque, and water temperature. As the water temperature rises during the day, the reference electrode reading becomes less negative and the electrical current decreases. Subsea water currents cause about a four-time increase in the bolt corrosion rate, with unprotected bolts suffering a nine-time-higher corrosion rate than protected bolts. A unique supply–demand interaction is observed; less protection is supplied to areas with lower corrosion rates (lower demand for protection). Finally, scanning electron microscopy examination reveals new insights into the failure mechanisms of subsea bolts.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"31 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140743692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-07DOI: 10.1149/2754-2734/ad3121
Anand Sagar, S. Chugh, E. Kjeang
Open-cathode polymer electrolyte membrane fuel cells (PEMFCs) utilize a unique air-cooled system design to eliminate the humidifiers, air compressor, and liquid cooling loop of conventional, liquid-cooled PEMFC systems, thereby greatly reducing system cost. However, the open-cathode PEMFC performance is restricted by poor humidification, high membrane and charge transfer resistances, and overheating due to inefficient thermal and water management. This work aims to strategically modify the membrane electrode assembly (MEA) design to overcome these issues and achieve high open-cathode PEMFC performance that approaches that of liquid-cooled systems. The use of thinner membrane along with short side chain ionomer is found to elevate the cell performance due to increased water retention at the cathode catalyst layer (CCL) and decreased ohmic losses. Thinner gas diffusion layers with high porosity enable additional cell performance increment by improving oxygen availability at the CCL. An overall current density rise of 88% at 0.6 V and 53% at 0.4 V is achieved by the strategically designed MEA for open-cathode cells. The enhanced power density enabled by the custom MEA can both reduce the stack cost and expand the power range of open-cathode PEMFCs, thus expanding their potential use for low-cost fuel cell system applications.
开放阴极聚合物电解质膜燃料电池（PEMFC）采用独特的空气冷却系统设计，省去了传统液体冷却 PEMFC 系统的加湿器、空气压缩机和液体冷却回路，从而大大降低了系统成本。然而，开阴极 PEMFC 的性能受到了以下因素的限制：加湿效果差、膜电阻和电荷转移电阻高，以及热管理和水管理效率低下导致的过热。这项研究旨在对膜电极组件（MEA）的设计进行战略性修改，以克服这些问题，实现接近液体冷却系统的开阴极 PEMFC 高性能。由于阴极催化剂层（CCL）的保水性提高和欧姆损耗降低，使用更薄的膜和短侧链离子聚合物可提高电池性能。较薄的气体扩散层具有较高的孔隙率，通过提高 CCL 的氧气可用性，使电池性能得到进一步提高。通过为开式阴极电池战略性地设计 MEA，0.6 V 和 0.4 V 电压下的电流密度分别提高了 88% 和 53%。定制 MEA 带来的功率密度提升既能降低堆栈成本，又能扩大开放阴极 PEMFC 的功率范围，从而扩大其在低成本燃料电池系统应用中的潜在用途。
{"title":"Experimental Design of High-Performing Open-Cathode Polymer Electrolyte Membrane Fuel Cells","authors":"Anand Sagar, S. Chugh, E. Kjeang","doi":"10.1149/2754-2734/ad3121","DOIUrl":"https://doi.org/10.1149/2754-2734/ad3121","url":null,"abstract":"\u0000 Open-cathode polymer electrolyte membrane fuel cells (PEMFCs) utilize a unique air-cooled system design to eliminate the humidifiers, air compressor, and liquid cooling loop of conventional, liquid-cooled PEMFC systems, thereby greatly reducing system cost. However, the open-cathode PEMFC performance is restricted by poor humidification, high membrane and charge transfer resistances, and overheating due to inefficient thermal and water management. This work aims to strategically modify the membrane electrode assembly (MEA) design to overcome these issues and achieve high open-cathode PEMFC performance that approaches that of liquid-cooled systems. The use of thinner membrane along with short side chain ionomer is found to elevate the cell performance due to increased water retention at the cathode catalyst layer (CCL) and decreased ohmic losses. Thinner gas diffusion layers with high porosity enable additional cell performance increment by improving oxygen availability at the CCL. An overall current density rise of 88% at 0.6 V and 53% at 0.4 V is achieved by the strategically designed MEA for open-cathode cells. The enhanced power density enabled by the custom MEA can both reduce the stack cost and expand the power range of open-cathode PEMFCs, thus expanding their potential use for low-cost fuel cell system applications.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"32 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140077238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-02DOI: 10.1149/2754-2734/ad2f46
S. Farhad, Md Moazzem Hossain, M. S. Bashar, N. Tanvir, Suravi Islam
Highly-textured phase pure Cu2O thin films have been grown on fluorine-doped SnO2 substrates by a simple electrodeposition technique with varying deposition voltages (-0.3 to -1.0 V). Surface morphology characterization by scanning electron microscopy revealed that the deposited thin films coherently carpet the underlying substrate and are composed of sharp faceted well-defined grains of 0.5 – 1.0 µm sizes. The optical bandgap of the as-grown samples was calculated in the range of 1.95 – 2.20 eV. The performance of Cu2O films was tested by estimating LED 'ON/OFF' modulated surface photovoltage into a photoelectrochemical cell at a zero bias.
通过不同沉积电压（-0.3 至 -1.0 V）的简单电沉积技术，在掺氟二氧化锡基底上生长出了高纹理相纯的氧化铜薄膜。扫描电子显微镜的表面形貌表征显示，沉积的薄膜与底层基底连成一体，由 0.5 - 1.0 µm 大小的锐利切面清晰晶粒组成。根据计算，生长样品的光带隙在 1.95 - 2.20 eV 之间。Cu2O 薄膜的性能测试方法是在零偏压条件下，在光电化学电池中估算 LED "开/关 "调制表面光电压。
{"title":"Texture and Bandgap Tuning of Phase Pure Cu2O Thin Films Grown by a Simple Potentiostatic Electrodeposition Technique","authors":"S. Farhad, Md Moazzem Hossain, M. S. Bashar, N. Tanvir, Suravi Islam","doi":"10.1149/2754-2734/ad2f46","DOIUrl":"https://doi.org/10.1149/2754-2734/ad2f46","url":null,"abstract":"\u0000 Highly-textured phase pure Cu2O thin films have been grown on fluorine-doped SnO2 substrates by a simple electrodeposition technique with varying deposition voltages (-0.3 to -1.0 V). Surface morphology characterization by scanning electron microscopy revealed that the deposited thin films coherently carpet the underlying substrate and are composed of sharp faceted well-defined grains of 0.5 – 1.0 µm sizes. The optical bandgap of the as-grown samples was calculated in the range of 1.95 – 2.20 eV. The performance of Cu2O films was tested by estimating LED 'ON/OFF' modulated surface photovoltage into a photoelectrochemical cell at a zero bias.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"36 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140081684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-15DOI: 10.1149/2754-2734/ad29d4
Youyi Sun
By comparing the catalytic activity of the hydrogen evolution reaction (HER) from various metals, we find that metals with high EN and containing two or more accessible partially filled orbitals ( PFOs) can support high exchange current density i0,H(A cm - 2 ) for HER. However, metals with low EN and/or with just one or no PFOs are unable to support high i0,H values. It is concluded that the EN and PFOs of the metal atoms play a decisive role in catalytic behavior. EN and VEC of the atoms of transition metals in relation to catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is suggested
通过比较各种金属对氢进化反应（HER）的催化活性，我们发现EN值高且含有两个或更多可触及的部分填充轨道（PFO）的金属可支持氢进化反应的高交换电流密度i0,H（A cm - 2）。然而，EN 值低和/或只有一个或没有 PFO 的金属则无法支持较高的 i0,H 值。由此得出结论，金属原子的EN 和 PFO 在催化行为中起着决定性作用。讨论了过渡金属原子的EN 和 VEC 与 HER 催化活化的关系，并提出了 HER 在各种金属电极上的新型反应机制
{"title":"Perspective—A New View on the Mechanism of the Hydrogen Evolution Reaction on Various Transition Metal Electrodes","authors":"Youyi Sun","doi":"10.1149/2754-2734/ad29d4","DOIUrl":"https://doi.org/10.1149/2754-2734/ad29d4","url":null,"abstract":"\u0000 By comparing the catalytic activity of the hydrogen evolution reaction (HER) from various metals, we find that metals with high EN and containing two or more accessible partially filled orbitals ( PFOs) can support high exchange current density i0,H(A cm - 2 ) for HER. However, metals with low EN and/or with just one or no PFOs are unable to support high i0,H values. It is concluded that the EN and PFOs of the metal atoms play a decisive role in catalytic behavior. EN and VEC of the atoms of transition metals in relation to catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is suggested","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"193 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139836089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-15DOI: 10.1149/2754-2734/ad29d4
Youyi Sun
By comparing the catalytic activity of the hydrogen evolution reaction (HER) from various metals, we find that metals with high EN and containing two or more accessible partially filled orbitals ( PFOs) can support high exchange current density i0,H(A cm - 2 ) for HER. However, metals with low EN and/or with just one or no PFOs are unable to support high i0,H values. It is concluded that the EN and PFOs of the metal atoms play a decisive role in catalytic behavior. EN and VEC of the atoms of transition metals in relation to catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is suggested
通过比较各种金属对氢进化反应（HER）的催化活性，我们发现EN值高且含有两个或更多可触及的部分填充轨道（PFO）的金属可支持氢进化反应的高交换电流密度i0,H（A cm - 2）。然而，EN 值低和/或只有一个或没有 PFO 的金属则无法支持较高的 i0,H 值。由此得出结论，金属原子的EN 和 PFO 在催化行为中起着决定性作用。讨论了过渡金属原子的EN 和 VEC 与 HER 催化活化的关系，并提出了 HER 在各种金属电极上的新型反应机制
{"title":"Perspective—A New View on the Mechanism of the Hydrogen Evolution Reaction on Various Transition Metal Electrodes","authors":"Youyi Sun","doi":"10.1149/2754-2734/ad29d4","DOIUrl":"https://doi.org/10.1149/2754-2734/ad29d4","url":null,"abstract":"\u0000 By comparing the catalytic activity of the hydrogen evolution reaction (HER) from various metals, we find that metals with high EN and containing two or more accessible partially filled orbitals ( PFOs) can support high exchange current density i0,H(A cm - 2 ) for HER. However, metals with low EN and/or with just one or no PFOs are unable to support high i0,H values. It is concluded that the EN and PFOs of the metal atoms play a decisive role in catalytic behavior. EN and VEC of the atoms of transition metals in relation to catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is suggested","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"14 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139776103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-09DOI: 10.1149/2754-2734/ad27dc
Ram Krishna Hona, Ebony Schultz, Mandy Guinn, Alexa D. Azure
We investigated the utility of Ca2FeMnO6-δ and Sr2FeMnO6-δ as materials with low thermal conductivity, finding potential applications in thermoelectrics, electronics, solar devices, and gas turbines for land and aerospace use. These compounds, characterized as oxygen-deficient perovskites, feature distinct vacancy arrangements. Ca2FeMnO6-δ adopts a brownmillerite-type orthorhombic structure with ordered vacancy arrangement, while Sr2FeMnO6-δ adopts a perovskite cubic structure with disordered vacancy distribution. Notably, both compounds exhibit remarkably low thermal conductivity, measuring below 0.50 Wm-1K-1. This places them among the materials with the lowest thermal conductivity reported for perovskites. The observed low thermal conductivity is attributed to oxygen vacancies and phonon scattering. Interestingly as scanning electron microscopy images show the smaller grain size, our findings suggest that the creation of vacancies and lowering the grain size or increasing the grain boundaries play a crucial role in achieving such low thermal conductivity values. This characteristic enhances the potential of these materials for applications where efficient heat dissipation, safety, and equipment longevity are paramount.
{"title":"Comparative Thermal Insulation Nature of Ca2FeMnO6-δ and Sr2FeMnO6-δ","authors":"Ram Krishna Hona, Ebony Schultz, Mandy Guinn, Alexa D. Azure","doi":"10.1149/2754-2734/ad27dc","DOIUrl":"https://doi.org/10.1149/2754-2734/ad27dc","url":null,"abstract":"\u0000 We investigated the utility of Ca2FeMnO6-δ and Sr2FeMnO6-δ as materials with low thermal conductivity, finding potential applications in thermoelectrics, electronics, solar devices, and gas turbines for land and aerospace use. These compounds, characterized as oxygen-deficient perovskites, feature distinct vacancy arrangements. Ca2FeMnO6-δ adopts a brownmillerite-type orthorhombic structure with ordered vacancy arrangement, while Sr2FeMnO6-δ adopts a perovskite cubic structure with disordered vacancy distribution. Notably, both compounds exhibit remarkably low thermal conductivity, measuring below 0.50 Wm-1K-1. This places them among the materials with the lowest thermal conductivity reported for perovskites. The observed low thermal conductivity is attributed to oxygen vacancies and phonon scattering. Interestingly as scanning electron microscopy images show the smaller grain size, our findings suggest that the creation of vacancies and lowering the grain size or increasing the grain boundaries play a crucial role in achieving such low thermal conductivity values. This characteristic enhances the potential of these materials for applications where efficient heat dissipation, safety, and equipment longevity are paramount.","PeriodicalId":489350,"journal":{"name":"ECS advances","volume":"312 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139848304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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