A5018081463- CO2 Reduction Techniques and Catalysts
- Advanced battery technologies research
- Carbon Dioxide Capture Technologies
- Electrocatalysts for Energy Conversion
- Ionic liquids properties and applications
- Molecular Junctions and Nanostructures
- Carbon Nanotubes in Composites
- Fuel Cells and Related Materials
- Catalysts for Methane Reforming
- Carbon dioxide utilization in catalysis
- Supercapacitor Materials and Fabrication
- Model Reduction and Neural Networks
- Advanced biosensing and bioanalysis techniques
- Electrochemical Analysis and Applications
- Microbial Fuel Cells and Bioremediation
- Membrane Separation and Gas Transport
- Additive Manufacturing and 3D Printing Technologies
- Magnetic Properties of Alloys
- Membrane-based Ion Separation Techniques
- Graphene research and applications
- Microfluidic and Capillary Electrophoresis Applications
- Catalysis and Oxidation Reactions
- Electrochemical sensors and biosensors
- Mechanical and Optical Resonators
- Nanomaterials for catalytic reactions
Lawrence Livermore National Laboratory
2016-2025
Materials Science & Engineering
2025
Lawrence Livermore National Security
2016-2021
University of San Diego
2014
University of Georgia
2009
University of Wisconsin–Madison
2002-2009
University of California, Santa Barbara
2007-2008
Zhejiang University
2008
Columbia University Irving Medical Center
2005
United States Naval Research Laboratory
2005
Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the solvent from infrastructure effluent gases via microencapsulation provides possible solutions to these issues. Here we report materials that may enable low-cost energy-efficient flue gas. Polymer microcapsules composed liquid carbonate cores highly permeable silicone shells are produced by microfluidic assembly. This motif couples capacity selectivity sorbents with high...
Abstract Alkaline water electrolysis at high current densities is plagued by gas bubble generation and trapping in stochastic porous electrodes (e.g., Ni foams), which causes a significant reduction the number of electrolyte accessible catalyst active sites. Here, 3D printed (3DPNi) with highly controlled, periodic structures are reported that suppress coalescence, jamming, and, hence, result rapid release. The 3DPNi decorated carbon‐doped NiO achieve density 1000 mA cm −2 1.0 m KOH hydrogen...
In low-temperature C O 2 electrolysis, a fundamental trade-off exists between maximizing electrolyzer performance and minimizing downstream recovery. By coupling down-the-gas-channel model with techno-economic analysis, we find that the optimal single-pass conversion for ethylene production is typically low—on order of 5%–10%—although larger optima are found if H faradic efficiency very low. Similarly, strategies eliminating carbonate crossover require more energy than gas separation they...
We have developed a multistep route to the formation of covalently linked adducts single-wall carbon nanotubes (SWNT) and deoxyribonucleic acid (DNA) oligonucleotides. X-ray photoelectron spectroscopy was used characterize initial chemical modification form amine-terminated SWNTs, which were then DNA. The resulting DNA−SWNT hybridize selectively with complementary sequences, only minimal interaction noncomplementary sequences.
Exposing single-walled carbon nanotubes to room-temperature UV-generated ozone leads an irreversible increase in their electrical resistance. We demonstrate that the increased resistance is due oxidation on sidewalls of rather than at end caps. Raman and X-ray photoelectron spectroscopies show defect density nanotubes. Using ultraviolet spectroscopy, we these defects represent removal π-conjugated electron states near Fermi level, leading observed Oxidation important first step many chemical...
Abstract An industrial process for the selective activation of methane under mild conditions would be highly valuable controlling emissions to environment and utilizing vast new sources natural gas. The only catalysts conversion methanol are monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes not amenable standard enzyme immobilization approaches. Using particulate monooxygenase (pMMO), we create a biocatalytic polymer material that converts methanol. We...
Formate is an important value-added chemical that can be produced via electrochemical CO2 reduction reactions (CO2RR). Cu2O-based catalysts have previously demonstrated decent activity for formate generation; however, they often suffer from poor stability under reductive conditions. Here, we report a new Cu2O/CuS composite catalyst simultaneously achieves excellent faradaic efficiency of 67.6% and large partial current density 15.3 mA/cm2 at −0.9 V vs RHE formate. Importantly, it maintains...
Critical to the success of three-dimensional (3D) printing living materials with high performance is development new ink and 3D geometries that favor long-term cell functionality. Here we report use freeze-dried live cells as solid filler enable a material system for direct writing catalytically active microorganisms tunable densities various self-supporting porous geometries. Baker's yeast was used an exemplary whole-cell biocatalyst, printed structures displayed resolution, large scale,...
Abstract The electrosynthesis of value‐added multicarbon products from CO 2 is a promising strategy to shift chemical production away fossil fuels. Particularly important the rational design gas diffusion electrode (GDE) assemblies react selectively, at scale, and high rates. However, understanding layer (GDL) in these limited for reduction reaction (CO RR): particularly important, but incompletely understood, how GDL modulates product distributions catalysts operating current density...
Changing the reactor design paradigm for improved CO<sub>2</sub>electrolyzers through advanced manufacturing.
Engineering the electrolyte microenvironment represents an attractive route to tuning selectivity of electrocatalytic reactions beyond catalyst composition and morphology. However, harnessing full potential this approach requires understanding interplay between voltage, composition, adsorbate binding within electrical double layer, which is absent from usual theoretical approaches. In work, we apply a recently developed density functional theory (DFT)-continuum based on effective screening...
Significance The efficient utilization of electrical energy is an increasingly important challenge, especially as renewable sources become cheaper and demand increases. Electrochemical reactors utilizing flow-through electrodes (FTEs) provide attractive path toward the energy. Their commercial viability ultimate adoption hinge on attaining high current densities to drive cost competitiveness. There are limited opportunities for engineering FTE materials, these often random, disordered media....
CO2 emissions can be transformed into high-added-value commodities through electrocatalysis; however, efficient low-cost electrocatalysts are needed for global scale-up. Inspired by other emerging technologies, the authors report development of a gas diffusion electrode containing highly dispersed Ag sites in Zn matrix. This catalyst shows unprecedented mass activity CO production: -614 mA cm-2 at 0.17 mg Ag. Subsequent electrolyte engineering demonstrates that halide anions further improve...
We demonstrate the electrically addressable biomolecular functionalization of single-walled carbon nanotube electrodes and vertically aligned nanofiber electrodes. The method uses an electrochemical reaction in which nitro groups on specific nanostructures are reduced to amino then used covalently link DNA only these nanostructures. fabrication a four-element array distinct oligonucleotides submicron bundles <100 nm diameter nanofibers. hybridization shows that DNA-modified nanoscale...
Layered clays are shown to have a wide range of blood-clotting properties that appear be influenced by surface charge. The most active clay clotting agent is as effective commercial zeolite hemostatic material, but does not release heat, making it promising alternative the zeolite.
A panel of five zinc-chelated aza-macrocycle ligands and their ability to catalyze the hydration carbon dioxide bicarbonate, H2O + CO2 → H+ HCO3–, was investigated using quantum-mechanical methods stopped-flow experiments. The key intermediates in reaction coordinate were optimized M06-2X density functional with aug-cc-pVTZ basis set. Activation energies for first step catalytic cycle, nucleophilic addition, calculated from gas-phase transition-state geometries. computationally derived trend...
Zinc(II) cyclen, a small molecule mimic of the enzyme carbonic anhydrase, was evaluated under rigorous conditions resembling those in an industrial carbon capture process: high pH (>12), nearly saturated salt concentrations (45% K2CO3) and elevated temperatures (100-130 °C). We found that catalytic activity zinc cyclen increased with increasing temperature retained after exposure to 45% w/w K2CO3 solution at 130 °C for 6 days. However, bicarbonate markedly reduced catalyst. Our results...
Purpose-designed, water-lean solvents have been developed to improve the energy efficiency of CO<sub>2</sub> capture from power plants, including CO<sub>2</sub>-binding organic liquids (CO<sub>2</sub>BOLs) and ionic (ILs). Many these are highly viscous or change phases, posing challenges for conventional process equipment. Such problems can be overcome by encapsulation. Micro-Encapsulated Sorbents (MECS) consist a CO<sub>2</sub>-absorbing solvent slurry encased in spherical,...
Bridging polymer design with catalyst surface science is a promising direction for tuning and optimizing electrochemical reactors that could impact long-term goals in energy sustainability. Particularly, the interaction between inorganic surfaces organic-based ionomers provides an avenue to both steer reaction selectivity promote activity. Here, we studied role of imidazolium-based electrocatalytic CO2 reduction CO (CO2R) on Ag found they produce no effect CO2R activity yet strongly...