Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Understanding water management in platinum group metal-free electrodes using neutron imaging.

ABSTRACT: Platinum group metal-free (PGM-free) catalysts are a low-cost alternative to expensive PGM catalysts for polymer electrolyte fuel cells. However, due to the low volumetric activity of PGM-free catalysts, the catalyst layer thickness of the PGM-free catalyst electrode is an order of magnitude higher than PGM based electrodes. The thick PGM-free electrodes suffer from increased transport resistance and poor water management, which ultimately limits the fuel cell performance. This manuscript presents the study of water management in the PGM-free electrodes to understand the transport limitations and improve fuel cell performance. In-operando neutron imaging is performed to estimate the water content in different components across the fuel cell thickness. Water saturation in thick PGM electrodes, with similar catalyst layer thickness to PGM-free electrodes, is lower than in the PGM-free electrodes irrespective of the operating conditions, due to high water retention by PGM-free catalysts. Improvements in fuel cell performance are accomplished by enhancing water removal from the flooded PGM-free electrode in three ways: (i) enhanced water removal with a novel microporous layer with hydrophilic pathways incorporated through hydrophilic additives, (ii) water removal through anode via novel GDL in the anode, and (iii) lower water saturation in PGM-free electrode structures with increased catalyst porosity.

SUBMITTER: Babu SK

PROVIDER: S-EPMC8628569 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Influence of platinum group metal-free catalyst synthesis on microbial fuel cell performance.

Project description:Platinum group metal-free (PGM-free) ORR catalysts from the Fe-N-C family were synthesized using sacrificial support method (SSM) technique. Six experimental steps were used during the synthesis: 1) mixing the precursor, the metal salt, and the silica template; 2) first pyrolysis in hydrogen rich atmosphere; 3) ball milling; 4) etching the silica template using harsh acids environment; 5) the second pyrolysis in ammonia rich atmosphere; 6) final ball milling. Three independent batches were fabricated following the same procedure. The effect of each synthetic parameters on the surface chemistry and the electrocatalytic performance in neutral media was studied. Rotating ring disk electrode (RRDE) experiment showed an increase in half wave potential and limiting current after the pyrolysis steps. The additional improvement was observed after etching and performing the second pyrolysis. A similar trend was seen in microbial fuel cells (MFCs), in which the power output increased from 167 ± 2 μW cm-2 to 214 ± 5 μW cm-2. X-ray Photoelectron Spectroscopy (XPS) was used to evaluate surface chemistry of catalysts obtained after each synthetic step. The changes in chemical composition were directly correlated with the improvements in performance. We report outstanding reproducibility in both composition and performance among the three different batches.

| S-EPMC5738968 | biostudies-literature

Probing transport limitations in thick sintered battery electrodes with neutron imaging.

Project description:Lithium-ion batteries have received significant research interest due to their advantages in energy and power density, which are important to enabling many devices. One route to further increase energy density is to fabricate thicker electrodes in the battery cell; however, careful consideration must be taken when designing electrodes as to how increasing the thickness impacts the multiscale and multiphase molecular transport processes, which can limit the overall battery operating power. Design of these electrodes necessitates probing the molecular processes when the battery cell undergoes electrochemical charge/discharge. One tool for in situ insights into the cell is neutron imaging, because neutron imaging can provide information of where electrochemical processes occur within the electrodes. In this manuscript, neutron imaging is applied to track the lithiation/delithiation processes within electrodes at different current densities for a full cell with a thick sintered Li4Ti5O12 anode and LiCoO2 cathode. The neutron imaging reveals that the molecular distribution of Li+ during discharge within the electrode is sensitive to the current density, or equivalently discharge rate. An electrochemical model provides additional insights into the limiting processes occurring within the electrodes. In particular, the impact of tortuosity and molecular transport in the liquid phase within the interstitial regions in the electrodes are considered, and the influence of tortuosity was shown to be highly sensitive to the current density. Qualitatively, the experimental results suggest that the electrodes behave consistent with the packed hard sphere approximation of Bruggeman tortuosity scaling, which indicates that the electrodes are largely mechanically intact but also that a design that incorporates tunable tortuosity could improve the performance of these types of electrodes.

| S-EPMC8739910 | biostudies-literature

Metal Sulphides and Their Carbon Supported Composites as Platinum-Free Counter Electrodes in Dye-Sensitized Solar Cells: A Review.

Project description:Energy sufficiency is a critical requirement for the economic prosperity of modern countries. Efficient harnessing of solar energy using technologies such as the dye-sensitized solar cell could solve the energy problem which persistently plagues developing countries. Despite having a simple operational procedure and modest power conversion efficiency of 13.8%, the dye-sensitized solar cell consists of an expensive platinum counter electrode which makes commercial success futile. Thus, this review intends to establish the progress researchers have attained in the development of sulphide based counter electrodes as alternatives to platinum, thereby lowering cost of production. Metallic sulphides are good electrocatalysts and cheap, hence, they possess the necessary requirements for effective functional counter electrodes. Furthermore, ternary metallic sulphides are known to exhibit higher efficiencies stemming from the synergistic effect produced by the co-existence of two metal ions in a crystal structure, which is believed to induce greater catalytic capability. Incorporation of metallic sulphides with carbon materials, which are exceptional electrical conductors, could potentially produce more efficient counter electrodes. In that regard, this review seeks to establish the effect recently developed composite counter electrodes comprising metallic sulphides and carbon-based materials have induced on the functionality of the counter electrode (CE).

| S-EPMC6630930 | biostudies-literature

Oxidative strong metal-support interactions (OMSI) of supported platinum-group metal catalysts.

Project description:Supported platinum-group metal (PGM) catalysts are widely used in many important industrial processes. Metal-support interaction is of great importance in tailoring their catalytic performance. Here, we report the first example of oxidative strong metal-support interactions (OMSIs) between PGM and hydroxyapatite (HAP) which can be extended to PGM and ZnO. It occurred under high-temperature oxidation conditions accompanied by the encapsulation of PGM by HAP and electron transfer between PGM and HAP. With this OMSI, the aggregation and leaching of PGMs were significantly inhibited, resulting in an excellent catalytic stability and much improved reusability of supported Pt and Pd catalysts, respectively. This is the first time to find that PGMs can manifest OMSI which benefits the stabilization of PGM catalysts under oxidative reaction conditions. This new type of SMSI not only contributed to a deeper understanding of SMSI but also provided a new way to develop new stable PGM catalysts.

| S-EPMC6115625 | biostudies-literature

Alternative electrodes for HTMs and noble-metal-free perovskite solar cells: 2D MXenes electrodes.

Project description:The high cost of hole transporting materials (HTMs) and noble metal electrodes limits the application of perovskite solar cells (PSCs). Carbon materials have been commonly utilized for HTMs and noble-metal-free PSCs. In this paper, a more conductive 2D MXene material (Ti3C2), showing a similar energy level to carbon materials, has been used as a back electrode in HTMs and noble-metal-free PSCs for the first time. Seamless interfacial contact between the perovskite layer and Ti3C2 material was obtained using a simple hot-pressing method. After the adjustment of key parameters, the PSCs based on the Ti3C2 electrode show more stability and higher power conversion efficiencies (PCE) (13.83%, 27% higher than that (10.87%) of the PSCs based on carbon electrodes) due to the higher conductivity and seamless interfacial contact of the MXene electrode. Our work proposes a promising future application for MXene and also a good electrode candidate for HTM and the noble-metal-free PSCs.

| S-EPMC9073695 | biostudies-literature

Investigation of dissimilar metal welds by energy-resolved neutron imaging.

Project description:A nondestructive study of the internal structure and compositional gradient of dissimilar metal-alloy welds through energy-resolved neutron imaging is described in this paper. The ability of neutrons to penetrate thick metal objects (up to several cm) provides a unique possibility to examine samples which are opaque to other conventional techniques. The presence of Bragg edges in the measured neutron transmission spectra can be used to characterize the internal residual strain within the samples and some microstructural features, e.g. texture within the grains, while neutron resonance absorption provides the possibility to map the degree of uniformity in mixing of the participating alloys and intermetallic formation within the welds. In addition, voids and other defects can be revealed by the variation of neutron attenuation across the samples. This paper demonstrates the potential of neutron energy-resolved imaging to measure all these characteristics simultaneously in a single experiment with sub-mm spatial resolution. Two dissimilar alloy welds are used in this study: Al autogenously laser welded to steel, and Ti gas metal arc welded (GMAW) to stainless steel using Cu as a filler alloy. The cold metal transfer variant of the GMAW process was used in joining the Ti to the stainless steel in order to minimize the heat input. The distributions of the lattice parameter and texture variation in these welds as well as the presence of voids and defects in the melt region are mapped across the welds. The depth of the thermal front in the Al-steel weld is clearly resolved and could be used to optimize the welding process. A highly textured structure is revealed in the Ti to stainless steel joint where copper was used as a filler wire. The limited diffusion of Ti into the weld region is also verified by the resonance absorption.

| S-EPMC4970494 | biostudies-literature

Understanding Cation Trends for Hydrogen Evolution on Platinum and Gold Electrodes in Alkaline Media.

Project description:In this work, we study how the cation identity and concentration alter the kinetics of the hydrogen evolution reaction (HER) on platinum and gold electrodes. A previous work suggested an inverted activity trend as a function of alkali metal cation when comparing the performance of platinum and gold catalysts in alkaline media. We show that weakly hydrated cations (K+) favor HER on gold only at low overpotentials (or lower alkalinity), whereas in more alkaline pH (or high overpotentials), a higher activity is observed using electrolytes containing strongly hydrated cations (Li+). We find a similar trend for platinum; however, the inhibition of HER by weakly hydrated cations on platinum is observed already at lower alkalinity and lower cation concentrations, suggesting that platinum interacts more strongly with metal cations than gold. We propose that weakly hydrated cations stabilize the transition state of the water dissociation step more favorably due to their higher near-surface concentration in comparison to a strongly hydrated cation such as Li+. However, at high pH and consequently higher near-surface cation concentrations, the accumulation of these species at the outer Helmholtz plane inhibits HER. This is especially pronounced on platinum, where a change in the rate-determining step is observed at pH 13 when using a Li+- or K+-containing electrolyte.

| S-EPMC8650008 | biostudies-literature

Multifunctional Water Sensors for pH, ORP, and Conductivity Using Only Microfabricated Platinum Electrodes.

Project description:Monitoring of the pH, oxidation-reduction-potential (ORP), and conductivity of aqueous samples is typically performed using multiple sensors. To minimize the size and cost of these sensors for practical applications, we have investigated the use of a single sensor constructed with only bare platinum electrodes deposited on a glass substrate. The sensor can measure pH from 4 to 10 while simultaneously measuring ORP from 150 to 800 mV. The device can also measure conductivity up to 8000 μS/cm in the range of 10 °C to 50 °C, and all these measurements can be made even if the water samples contain common ions found in residential water. The sensor is inexpensive (i.e., ~$0.10/unit) and has a sensing area below 1 mm², suggesting that the unit is cost-efficient, robust, and widely applicable, including in microfluidic systems.

| S-EPMC5539692 | biostudies-other

Understanding the metal free alginate gelation process.

Project description:Alginate is a natural polysaccharide that has been recently gaining increasing attention as a biomaterial in the field of tissue engineering due to its favourable biocompatibility and gelation properties. Alginate hydrogels are commonly made by ionic crosslinking in the presence of divalent cations. Only a few studies have attempted to prepare alginate hydrogels without the presence of metal cations. Here the formation of metal free alginate hydrogels in the presence of the amino-acid glutamine is investigated. The transition from sol to gel is monitored by rheological measurements in the viscoelastic regime that reveal how the charged or neutral form of glutamine induces deep differences in the gelling ability. In particular, we show that the storage, G', and loss, G'', moduli differ significantly by shifting the glutamine zwitterionic equilibrium. Protonated amino acid could induce a shielding effect of the electrostatic repulsion of the alginate chains. Stable gels are obtained in the presence of a larger amount of free organic acid that gives rise to chain crosslink junctions and chain-chain stabilization. This opens up the possibility of preparing metal-free alginate hydrogels based on amino acid equilibria being pH sensitive.

| S-EPMC9042680 | biostudies-literature

Air Breathing Cathodes for Microbial Fuel Cell using Mn-, Fe-, Co- and Ni-containing Platinum Group Metal-free Catalysts.

Project description:The oxygen reduction reaction (ORR) is one of the major factors that is limiting the overall performance output of microbial fuel cells (MFC). In this study, Platinum Group Metal-free (PGM-free) ORR catalysts based on Fe, Co, Ni, Mn and the same precursor (Aminoantipyrine, AAPyr) were synthesized using identical sacrificial support method (SSM). The catalysts were investigated for their electrochemical performance, and then integrated into an air-breathing cathode to be tested in "clean" environment and in a working microbial fuel cell (MFC). Their performances were also compared to activated carbon (AC) based cathode under similar conditions. Results showed that the addition of Mn, Fe, Co and Ni to AAPyr increased the performances compared to AC. Fe-AAPyr showed the highest open circuit potential (OCP) that was 0.307 ± 0.001 V (vs. Ag/AgCl) and the highest electrocatalytic activity at pH 7.5. On the contrary, AC had an OCP of 0.203 ± 0.002 V (vs. Ag/AgCl) and had the lowest electrochemical activity. In MFC, Fe-AAPyr also had the highest output of 251 ± 2.3 μWcm-2, followed by Co-AAPyr with 196 ± 1.5 μWcm-2, Ni-AAPyr with 171 ± 3.6 μWcm-2, Mn-AAPyr with 160 ± 2.8 μWcm-2 and AC 129 ± 4.2 μWcm-2. The best performing catalyst (Fe-AAPyr) was then tested in MFC with increasing solution conductivity from 12.4 mScm-1 to 63.1 mScm-1. A maximum power density of 482 ± 5 μWcm-2 was obtained with increasing solution conductivity, which is one of the highest values reported in the field.

| S-EPMC5384433 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data