Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

High-resolution neutron imaging of salt precipitation and water transport in zero-gap CO₂ electrolysis.

ABSTRACT: The electrochemical reduction of CO₂ is a pivotal technology for the defossilization of the chemical industry. Although pilot-scale electrolyzers exist, water management and salt precipitation remain a major hurdle to long-term operation. In this work, we present high-resolution neutron imaging (6 μm) of a zero-gap CO₂ electrolyzer to uncover water distribution and salt precipitation under application-relevant operating conditions (200 mA cm^-2 at a cell voltage of 2.8 V with a Faraday efficiency for CO of 99%). Precipitated salts penetrating the cathode gas diffusion layer can be observed, which are believed to block the CO₂ gas transport and are therefore the major cause for the commonly observed decay in Faraday efficiency. Neutron imaging further shows higher salt accumulation under the cathode channel of the flow field compared to the land.

SUBMITTER: Disch J

PROVIDER: S-EPMC9569375 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

High-resolution neutron imaging of salt precipitation and water transport in zero-gap CO2 electrolysis.

Disch Joey J Bohn Luca L Koch Susanne S Schulz Michael M Han Yiyong Y Tengattini Alessandro A Helfen Lukas L Breitwieser Matthias M Vierrath Severin S

Nature communications 20221015 1

The electrochemical reduction of CO2 is a pivotal technology for the defossilization of the chemical industry. Although pilot-scale electrolyzers exist, water management and salt precipitation remain a major hurdle to long-term operation. In this work, we present high-resolution neutron imaging (6 μm) of a zero-gap CO2 electrolyzer to uncover water distribution and salt precipitation under application-relevant operating conditions (200 mA cm-2 at a cell voltage o ...[more]

PMID: 36243867

Similar Datasets

Cathodic Protection System against a Reverse-Current after Shut-Down in Zero-Gap Alkaline Water Electrolysis.

Project description:Growing the hydrogen economy requires improving the stability, efficiency, and economic value of water-splitting technology, which uses an intermittent power supply from renewable energy sources. Alkaline water electrolysis systems face a daunting challenge in terms of stabilizing hydrogen production under the condition of transient start-up/shut-down operation. Herein, we present a simple but effective solution for the electrode degradation problem induced by the reverse-current under transient power condition based on a fundamental understanding of the degradation mechanism of nickel (Ni). It was clearly demonstrated that the Ni cathode was irreversibly oxidized to either the β-Ni(OH)2 or NiO phases by the reverse-current flow after shut-down, resulting in severe electrode degradation. It was also determined that the potential of the Ni electrode should be maintained below 0.6 VRHE under the transient condition to keep a reversible nickel phase and an activity for the hydrogen evolution reaction. We suggest a cathodic protection approach in which the potential of the Ni electrode is maintained below 0.6 VRHE by the dissolution of a sacrificial metal to satisfy the above requirement; irreversible oxidization of the cathode is prevented by connecting a sacrificial anode to the Ni cathode. In the accelerated durability test under a simulated reverse-current condition, lead was found to be the most promising candidate for the sacrificial metal, as it is cost effective and demonstrates chemical stability in the alkaline media. A newly defined metric, a reverse-current stability factor, highlights that our system for protecting the cathode against the reverse-current is an efficient strategy for stable and cost effective alkaline hydrogen production.

| S-EPMC9709953 | biostudies-literature

Carbon black supported Ag nanoparticles in zero-gap CO2 electrolysis to CO enabling high mass activity.

Project description:In this study Ag nanoparticles supported on carbon black (Ag/C) were studied as catalysts for the electrochemical reduction of CO2 to CO. The nanoparticles were synthesized on three carbon supports, namely Super P, Vulcan and Ketjenblack with surface areas from 50 to 800 m2 g-1 using cysteamine as a linker as proposed by Kim et al., J. Am. Chem. Soc., 2015, 137, 13844. Gas diffusion electrodes were fabricated with all three Ag/Cs and then characterized in a zero-gap electrolyzer. All three supported catalysts achieve high voltage efficiencies, mass activities, and faradaic efficiencies above 80% up to 200 mA cm-2 with Ag loadings of ∼0.07 mg cm-2. Using an IrO2 anode, a partial CO current density of 196 mA cm-2 at 2.95 V and a mass activity of 3920 mA mg-1 at a cell voltage of 3.2 V was achieved. When changing the electrolyte from 0.1 M KOH to 0.1 M CsOH, it is possible to achieve 90% FECO at 300 mA cm-2. This results in a mass activity up to 5400 mA mg-1. Moreover, long-term tests at 300 mA cm-2 with 0.1 M CsOH resulted in FECO remaining above 80% over 11 h. The electrochemical performance did not show a dependence on the carbon support, indicating that mass transport is limiting the cathode, rather than catalyst kinetics. It is worth noting that this may only apply to electrodes with PTFE binders as used in this study, and electrodes with ionomer binders may show a dependence on the catalyst support.

| S-EPMC10283028 | biostudies-literature

Competitive Salt Precipitation/Dissolution During Free-Water Reduction in Water-in-Salt Electrolyte.

Project description:Water-in-salt electrolytes based on highly concentrated bis(trifluoromethyl)sulfonimide (TFSI) promise aqueous electrolytes with stabilities nearing 3 V. However, especially with an electrode approaching the cathodic (reductive) stability, cycling stability is insufficient. While stability critically relies on a solid electrolyte interphase (SEI), the mechanism behind the cathodic stability limit remains unclear. Now, two distinct reduction potentials are revealed for the chemical environments of free and bound water and that both contribute to SEI formation. Free water is reduced about 1 V above bound water in a hydrogen evolution reaction (HER) and is responsible for SEI formation via reactive intermediates of the HER; concurrent LiTFSI precipitation/dissolution establishes a dynamic interface. The free-water population emerges, therefore, as the handle to extend the cathodic limit of aqueous electrolytes and the battery cycling stability.

| S-EPMC7540070 | biostudies-literature

CO2 Electrolysis Technologies: Bridging the Gap toward Scale-up and Commercialization.

Project description:CO2 electroreduction (CO2E) converts CO2 into carbon-based fuels and chemical feedstocks that can be integrated into existing chemical processes. After decades of research, CO2E is approaching commercialization with several startups, pilot plants, and large initiatives targeting different products. Here, we analyze the global efforts in scaling up CO2E, addressing implementation challenges and proposing methods for acceleration. We present a comparative analysis of key performance indicators (KPIs) between laboratory and industrial settings and suggest a stepwise technoeconomic analysis (TEA) framework, supported by industrial data, exploiting interactions within the academic and industrial communities. We identify the lack of systems-oriented standardization and durability as the main bottlenecks slowing down progress in the lab-to-prototype-to-market pathway of CO2E technologies. Inspired by electrolysis and fuel cell technologies, we outline protocols to advance fundamental research and aid catalyst development progress in performance, upscaling, and technology readiness level of CO2E.

| S-EPMC11406523 | biostudies-literature

Zero-gap semiconductor to excitonic insulator transition in Ta2NiSe5.

Project description:The excitonic insulator is a long conjectured correlated electron phase of narrow-gap semiconductors and semimetals, driven by weakly screened electron-hole interactions. Having been proposed more than 50 years ago, conclusive experimental evidence for its existence remains elusive. Ta2NiSe5 is a narrow-gap semiconductor with a small one-electron bandgap EG of <50 meV. Below TC=326 K, a putative excitonic insulator is stabilized. Here we report an optical excitation gap Eop ∼0.16 eV below TC comparable to the estimated exciton binding energy EB. Specific heat measurements show the entropy associated with the transition being consistent with a primarily electronic origin. To further explore this physics, we map the TC-EG phase diagram tuning EG via chemical and physical pressure. The dome-like behaviour around EG∼0 combined with our transport, thermodynamic and optical results are fully consistent with an excitonic insulator phase in Ta2NiSe5.

| S-EPMC5316885 | biostudies-literature

Reference Electrode Types for Zero-Gap CO2 Electrolyzers: Benefits and Limitations.

Project description:Integrated reference electrodes allow to deconvolute voltage contributions of anode and cathode and contribute to a better understanding of CO2 electrolyzers. However, in zero-gap cell configurations, this integration can be challenging and obtaining error-free data with such a setup is a non-trivial task. This study compares five different methods to integrate a reference electrode into an alkaline zero-gap CO2 electrolysis cell. Sources of error and measures to circumvent them are investigated and finite-element simulation is used to gain a better understanding of observed effects. Placing a reference electrode into the inactive area of the cell is found to be a reliable method, as long as the placement of electrodes is sufficiently controlled. Sandwiching a wire quasi-reference electrode between two membranes is especially useful for electrochemical impedance spectroscopy; however, it can affect the overall cell performance. Contacting the catalyst layer from the backside with a salt-bridge is promising for localized measurements if sufficient reproducibility can be ensured.

| S-EPMC11348192 | biostudies-literature

Transport gap in SmB6 protected against disorder.

Project description:The inverted resistance method was used in this study to extend the bulk resistivity of [Formula: see text] to a regime where the surface conduction overwhelms the bulk. Remarkably, regardless of the large off-stoichiometric growth conditions (inducing disorder by samarium vacancies, boron interstitials, etc.), the bulk resistivity shows an intrinsic thermally activated behavior that changes ∼7-10 orders of magnitude, suggesting that [Formula: see text] is an ideal insulator that is immune to disorder.

| S-EPMC6601007 | biostudies-literature

Tunable Selectivity and High Efficiency of CO2 Electroreduction via Borate-Enhanced Molten Salt Electrolysis.

Project description:Converting CO2 into value-added chemical fuels and functional materials by CO2 reduction reaction (CO2RR) is conducive to achieving a carbon-neutral energy cycle. However, it is still challenging to efficiently navigate CO2RR toward desirable products. Herein, we report a facile strategy to extend product species in borate-containing molten electrolyte at a positively shifted cathodic potential with a high current density (e.g. 100 mA/cm2), which can selectively electro-transform CO2 into desired products (either CO or solid carbon nanofibers, respectively reaching a high selectivity of ∼90%). The borates can act as a controller of electrolyte alkalinity to buffer the concentration of sequentially generated O2- during CO2RR, positively shifting the reduction potential of the captured CO2 and concurrently extending the product species. The sustainable buffering effect is available under CO2 atmosphere. Compared with borate-free electrolyte, the CO2 conversion efficiency is over three times higher, while the electrolysis energy consumption is decreased by over 40%.

| S-EPMC7648164 | biostudies-literature

Preventing Salt Precipitation in CO2 Storage Processes in Saline Aquifers: Dissolved-Water CO2 Injection Method.

Project description:CO2 storage in geological formations, particularly deep saline aquifers, is a critical component of carbon capture and storage technology, offering significant potential for mitigating greenhouse gas emissions. However, high salinity of these aquifers poses the risk of salt precipitation, leading to pressurization and injectivity reduction. Developing a method to prevent salt precipitation remains a challenge, and this is an area that this study is focused on. Dissolved-water CO2 injection (dwCO2 injection) is proposed here as a novel method to prevent salt precipitation where water is dissolved in CO2 before injection into an aquifer. Presence of water in the CO2 stream prevents more dissolution of water into CO2 (evaporation) and, hence, prevents salt precipitation. Before presenting this method and in order to provide a good mechanistic understanding of the interactions involved in a CO2 storage process, six different scenarios are examined using the CMG-GEM simulator within a carbonate aquifer. The results showed that saturating CO2 with water reduced the precipitation nearly to zero, and dissolving 2000 ppmv water decreased the salt precipitation to one-third. It should be noted that injection of humid CO2 requires special methods to tackle the potential challenges, including corrosion and hydrate formation risks, and the paper also discusses them.

| S-EPMC11874032 | biostudies-literature

Photoenhanced Water Electrolysis in Separate O2 and H2 Cells Using Pseudocapacitive Electrodes.

Project description:Water electrolysis has received much attention in recent years as a means of sustainable H2 production. However, many challenges remain in obtaining high-purity H2 and making large-scale production cost-effective. This study provides a strategy for integrating a two-cell water electrolysis system with solar energy storage. In our proposed system, CuO-Cu(OH)2/Cu2O was used as a redox mediator between oxygen and hydrogen evolution components. The system not only overcame the gas-mixing issue but also showed high gas generation performance. The redox reaction (charge/discharge) of CuO-Cu(OH)2/Cu2O led to a significant increase (51%) in the initial rate of H2 production from 111.7 μmol h-1 cm-2 in the dark to 168.9 μmol h-1 cm-2 under solar irradiation. The effects of light on the redox reaction of CuO-Cu(OH)2/Cu2O during water electrolysis were investigated by in situ X-ray absorption and photoemission spectroscopy. These results suggest that surface oxygen vacancies are created under irradiation and play an important role in increased capacitance and gas generation. These findings provide a new path to direct storage of abundant solar energy and low-cost sustainable hydrogen production.

| S-EPMC8340381 | biostudies-literature