A5086049722- Electrochemical Analysis and Applications
- Electrocatalysts for Energy Conversion
- Electrostatics and Colloid Interactions
- CO2 Reduction Techniques and Catalysts
- Nanopore and Nanochannel Transport Studies
- Fuel Cells and Related Materials
- Ionic liquids properties and applications
- Conducting polymers and applications
- Advanced battery technologies research
- Lattice Boltzmann Simulation Studies
- Hybrid Renewable Energy Systems
- CO2 Sequestration and Geologic Interactions
- Enhanced Oil Recovery Techniques
- Energy and Environment Impacts
- Breastfeeding Practices and Influences
- Geophysical and Geoelectrical Methods
- Heat and Mass Transfer in Porous Media
- Advanced Battery Technologies Research
- Electrodeposition and Electroless Coatings
- Molecular Junctions and Nanostructures
- Membrane-based Ion Separation Techniques
- Catalysts for Methane Reforming
- Membrane Separation Technologies
- Integrated Energy Systems Optimization
National Renewable Energy Laboratory
2022-2024
University of California, Irvine
2019-2023
Irvine University
2023
Advanced Energy (United States)
2021
Tufts University
2018
Medford Radiology Group
2018
Columbia University
2002
Abstract The electrochemical reduction of carbon dioxide to formic acid is a promising pathway improve CO 2 utilization and has potential applications as hydrogen storage medium. In this work, zero-gap membrane electrode assembly architecture developed for the direct synthesis from dioxide. key technological advancement perforated cation exchange membrane, which, when utilized in forward bias bipolar configuration, allows generated at interface exit through anode flow field concentrations up...
Gas diffusion layers (GDLs) are porous carbonaceous that widely used in energy conversion and storage devices. Simulation of water transport through GDLs, a polymer electrolyte fuel cell (PEFC), for example, typically uses goniometer-measured external contact angles. Until now, there is no well-developed method to obtain angles inside the GDLs. AlRatrout et al. developed an open-source code compute local at triple-phase points from segmented micro-X-ray computed tomography (X-ray CT) images...
This work utilizes EIS to elucidate the impact of catalyst-ionomer interactions and cathode hydroxide ion transport resistance (RCL,OH-) on cell voltage product selectivity for electrochemical conversion CO ethylene. When using same Cu catalyst a Nafion ionomer, varying ink dispersion electrode deposition methods results in change 2 orders magnitude RCL,OH- ca. 25% porosity. Decreasing improved ethylene Faradaic efficiency (FE), up ∼57%, decrease hydrogen FE, by ∼36%, reduction 1 V at 700...
Low-temperature electrochemical CO2 reduction has demonstrated high selectivity for CO when devices are operated with pure streams. However, there is currently a dearth of knowledge systems operating below 30% CO2, regime interesting coupling point sources. Here we examine the influence ionomer chemistry and cell conditions on at low concentrations. Utilizing advanced diagnostics, values cathode catalyst layer ionic resistance electrocatalyst capacitance as function relative humidity (RH)...
Carbon corrosion in catalyst layer of PEFCs showed two phases: first 500 AST cycles carbon corroded rapidly and thickness was lost, after that slowed down but a pore structure collapsed, increasing O 2 transport resistance.
Abstract Increasing development of wind and solar generation in the power sector can create economic opportunities for deployment water electrolyzers that produce hydrogen. Temporal variation marginal cost energy future decarbonized grids make it favorable to dispatchably ramp hydrogen production up down response low‐ high‐cost times. Using this strategy, low‐cost is enabled by are low‐capital tolerant frequent on/off cycling. Ramping a designated turndown ratio avoid performance degradation...
At an electrified interface of metal and electrolyte, ion concentration in the diffuse layer is different from bulk impacted by charge. The double-layer structure can significantly enhance local ionic conductivity. Understanding conductivity enhancement with conventional electrochemical measurements challenging; however, electrokinetic experiments be more useful probing conductivities. We used streaming-current for a range pH values to measure ζ-potential at metal–electrolyte interfaces....
We developed a method, by combining electrochemical and electrokinetic streaming current techniques to study ion distribution ionic conductivity in the diffuse part of double layer (EDL) metal-electrolyte interface, when potential is applied on metal potentiostat. this method an electrochemically clean polycrystalline gold (poly Au)-electrolyte interface measured zeta for various potentials, pH, concentration electrolyte. Specific adsorption chloride ions poly Au was studied comparing...
Electrochemical CO 2 reduction is a promising technology to capture and convert valuable chemicals. High Faradaic efficiencies of products are achieved with zero-gap alkaline electrolyzers supporting electrolyte at the anode (anolyte). Herein, we investigate effect anolyte on electrode properties such as catalyst utilization, ionic accessibility etc. cathode using electrochemical techniques cell configurations that avoid complexities related co-electrolysis. Using 1M KOH Cu...
In this paper, two unique selectivity trends of ML-PAP[5] membranes are discussed from the perspectives channel geometry, ion exclusion, and linear molecule transport.
Interfacial charging and ionic conductivity in the diffuse layer of polycrystalline platinum (poly-Pt)– nonadsorbing electrolyte interface were studied using a combined electrochemical–electrokinetic method. Assuming no specific adsorption ions, electronic charge on metal (metal charge) was found to increase monotonically for acidic, neutral, basic pH, with applied potential up 0.95 V versus SHE. Nonmonotonic not observed; however, saturate near-constant positive value at higher potentials,...
Surface charging characteristics at a polycrystalline Pt-electrolyte interface were studied using electrokinetic streaming current method integrated with in-situ electrochemical cell, which was developed by our group [1-3]. Experimentally, surface relations are determined from the potential-dependent capacitance data. For catalytic surfaces (e.g., platinum), this is challenging to apply due strong chemisorption properties of metal [4]. We measure charge in presence ions incorporating...
Since the 1970s, there has been a trend on part of physicians and other health practitioners to promote breastfeeding in United States, movement that not as successful hoped, since majority mothers this country continue feed their babies formula. Several socioeconomic factors are considered be barriers success promotion today. Yet, even among those who exists notable constraint dealing with issue sexuality breastfeeding. Indeed, female breast is eroticized Western society, promotional...
Gas diffusion layers (GDLs) are porous fiber that used for various electrochemical applications, including fuel cells, electrolyzers, CO2 reduction reaction and redox flow batteries. Depending on its application, a GDL’s wettability is controlled by the addition of polytetrafluoroethylene (PTFE). The PTFE highly stochastic, resulting in inhomogeneous distribution. Furthermore, fibers, carbonaceous binder, all have different surface roughness properties dictate GDL wettability. To determine...
A mechanistic understanding of carbon corrosion in polymer electrolyte fuel cells (PEFCs) is required to design catalyst layers that are durable. Electrochemical oxidation occurs during uncontrolled startup and shutdown events PEFCs leading multitude degradation events, including loss electrochemical surface area (ECSA), pore structure collapse, Pt detachment, ionomer others. To understand physics resulting mechanisms a detailed characterization needed probe interfaces between Pt-ionomer,...
CO 2 electrochemical reduction to useful chemicals has drawn significant interest over the past decade, as technology shows promising potential for coupling with renewable energies and helping reduce overall emission. 1 Among different (CO2R) end products, formate some economic advantages because it is easier downstream separation a liquid product, many applications, such hydrogen storage biomass conversion 3 . Several studies have shown that using SnO or Bi-based catalyst, Faradaic...
Electrochemical techniques, such as cyclic voltammetry and chronoamperometry are generally used to understand the reaction kinetics structure of electric double layer (EDL) formed at electrode-electrolyte interface. While these techniques can effectively probe Faradaic reactions, specific adsorption processes etc., they limited in their applicability towards measuring potential outer Helmholtz plane (OHP). On other hand, electrokinetic methods broadly measure slip plane, Zeta potential,...
We developed a novel technique combining electrochemistry and electrokinetics to understand the structure of electric double layers (EDLs) at metal-electrolyte interface, we applied it study polycrystalline Au (poly-Au)-electrolyte Pt (poly-Pt)-electrolyte interfaces. Traditional electrochemical methods are used Faradaic charge transfer reactions EDLs polarized interface. On other hand, electrokinetic methods, such as streaming current/potential ion distribution surface conductance ions in...
Electrochemical CO 2 reduction (CO R) devices have immense potential to capture the effluent in hard-to-decarbonize sectors and convert them valuable chemicals like CO, C H 4 , CH alcohols etc. Inside these devices, R occurs inside gas diffusion electrodes (GDE). The reaction rate strongly depends on local environment at catalyst-electrolyte interface ionomer binders, pH, electrolyte cations etc[1]. transport of reactants products from pore-space structure GDE, which comprises mostly micro...
Due to the high gravimetric energy density of hydrogen, focus implementation polymer electrolyte fuel cells (PEFCs) has shifted from light duty passenger vehicles heavy such as buses, trucks, locomotives and marine vessels 1 .A mechanistic understanding degradation is therefore necessary improve durability efficiency.During start-up shutdown (SUSD) PEFC systems, catalyst (Pt nanoparticles embedded on carbon support) undergoes local potentials ∼ -1.5 V caused by a combination (H 2 )...