Day 1 :
Keynote Forum
Lingzi Sang
University of Alberta , Canada
Keynote: Critical Interface in All-solid-state Li-ion Battery
Biography:
Lingzi Sang obtained her B.S. degree in Chemistry from Xiamen University (Xiamen, China) in 2009. She went on to the University of Arizona and obtained her Ph.D. in 2015. During this period, she developed molecular understandings associated to charge transfer efficiencies at the critical interfaces in organic photoelectronic devices. She then moved to Champaign-Urbana for her postdoctoral research at the University of Illinois under the supervision of Prof. Andrew A. Gewirth and Prof. Ralph G. Nuzzo. There she worked on multidisciplinary measurements at electrode and electrolyte interfaces in all-solid lithium ion batteries and unraveled molecular level origins that responsible to battery shorting and capacity fade. Lingzi joined the University of Alberta as an Assistant Professor Aug. 2018. The Sang research group focus on electrochemistry and spectroscopy measurements at critical interfaces in solid state energy conversion and storage systems.
Abstract:
The long-lasting environmental concerns arising from the use of fossil fuels and the rapid growth of renewable energy demand requires safe, large-scale, and reliable nextgeneration energy storage systems. All-solid-state lithium-ion batteries potentially offer enhanced energy and power density, and improved battery safety compared to the liquid electrolyte-based Li-ion batteries that are currently in use. Solid lithium-ion conductors such as thiophosphates are potential electrolyte materials for all-solid Li batteries because of their high Li+ ion conductivity, which is close to its liquid counterparts. Current challenges to achieving high performance all-solid-state batteries with long cycle life include shorting resulting predominantly from Li dendrite formation and infiltration through the solid electrolyte (SE), and increases in cell impedance induced by SE decomposition at the SE/electrode interface. In this work, we evaluate the electrochemical properties of two interlayer materials, Si and LiXAl(2-x/3)O3 (LiAlO), at the Li7P3S11 (LPS)/Li interface. Compared to the Li/LPS/Li symmetric cells in absence of interlayers, the presence of Si and LiAlO both significantly enhance the cycle number and total charge passing through the interface before failures resulting from cell shorting. In both cases, the noted improvements were accompanied by cell impedances that had increased substantially. The data reveal that both interlayers prevent the direct exposure of LPS to the metallic Li, and therefore eliminate the intrinsic LPS decomposition that occurs at Li surfaces before electrochemical cycling. After cycling, a reduction of LPS to Li2S at the interface when a Si interlayer is present; LiAlO, which functions to drop the potential between Li and LPS, suppresses LPS decomposition processes. The relative propensities towards SE decomposition follows from the electrochemical potentials at the interface which are dictated by the identities of the interlayer materials. This work provides new insights into the phase dynamics associated with specific choices for SE/electrode interlayer materials and the requirements they impose for realizing high efficiency, long lasting all-solid batteries.
Keynote Forum
Steven H. Bergens
University of Alberta, Canada
Keynote: Molecular Brick Building Sets for Chromophores and Catalysts for Solar-Powered Water Splitting and CO2 Reduction
Biography:
Bergens research develops new catalysts for electrochemical energy conversion, for preparation of chiral pharmaceuticals, and recently, for storage of sunlight in fuels. Energy research highlights include one of the first in-situ observations of dynamic water distributions in fuel cells made with Magnetic Resonance Imaging. He developed catalysts for methanol fuel cells with controlled surface compositions. He also developed bench top, open air, one reaction preparations of highly active, stable catalysts for water oxidation in acid and base. He recently discovered new, active photoelectrodes for solar-powered water oxidation, and active electrocatalysts for CO2 reduction that are being coupled with chromophores.
Abstract:
Dye-sensitized photoelectrochemical cells often utilize molecular dyes and catalysts bonded to semiconductors to absorb sunlight, split water, and reduce carbon dioxide in order to store solar engery in hydrocarbon form.1 We have developed molecular bricks that bond by covalent or electrostatic interactions. We will report on the use of these bricks to construct several systems to study visible light photoelectrochemical oxidations and reductions under acidic, neutral, and basic conditions. For example, we grafted 1,10-phenanthroline by a covalent bond at C5 to a variety of semiconductors and glassy carbon electrodes using diazonium chemistry.2,3 We then used this electrode-ligand brick to build a number of grafted [Ru(phensurface)(aromatic diamine)2]2+ chromophores by displacement of MeCN from the corresponding [Ru(MeCN)2(aromatic diamine)2]2+ precursors. Further, incorporation of one 1,10-phenanthroline-5,6-dione ligand into the Ru(MeCN)2 precursor allows for subsequent modifications of the chromophore after it is grafted to the electrode surface. Specifically, condensation reactions between the dione group in the grafted chromophore, and diamines in solution allowed for systematic tuning of the efficiency and wavelength range of the photoelectrode. As well, electrostatic self-assembly between the cationic Ru-chromophore surfaces and anionic, hydrous oxide Ir-Ni nanoparticle catalysts prepared test photoanodes for water splitting. Similar building reactions were used to covalently attach Mn- and Re-based CO2 reduction electrocatalysts to electrode surfaces.
- Nanotechnology in Environmental Research, Waste Water Minimization, Climate Change, Green Catalysis.
Location: WEBINAR
Session Introduction
Anthony Lau
University of British Columbia, BC, Canada
Title: Improving the Quality of Waste Biomass by Reducing the Ash Content and the Inorganic Constituents
Biography:
Anthony Lau obtained his BSc (Eng.) and MSc degrees in Agricultural Engineering from the University of Guelph and PhD degree in Interdisciplinary Studies/Bioresource Engineering from the University of British Columbia. Currently, he is an associate professor in the Department of Chemical and Biological Engineering at UBC. He is a member of the Biomass and Bioenergy Research Group within the Clean Energy Research Center. His research interest is in the area of waste management for resource recovery, focusing on two major sub-areas: 1) biomass feedstock engineering, and 2) bioconversion processes and systems. Biomass feedstock engineering may include the preprocessing, storage and quality improvement/management of lignocellulosic waste biomass as some of the major components of the supply chain logistics. Studies on bioconversion processes and systems are primarily aerobic composting and anaerobic fermentation of non-woody waste biomass.
Abstract:
Fuel pellets can be produced from forest residues and agricultural crop residues. This study aims at improving the quality of crop residues (canola straw, wheat straw and corn stover) by reducing the ash content and the inorganic constituents using mechanical size fractionation and water leaching in sequence as the pretreatment techniques. It is desirable to minimize the need for leaching, as the subsequent drying of the biomass for further processing into fuel pellets can be energy intensive thus increasing the production cost. Experimental treatments involve water temperature (25, 45°C), leaching time (3, 12, 24 h) and water-to-sample mass ratio (30:1) after preliminary tests were conducted to identify the appropriate levels for these parameters. Results indicated that the finest fraction of ground crop residues (particle size < 0.25 mm) had much higher ash contents than the coarser fractions up to 3.15 mm. Hence, size fractionation can effectively reduce the need for leaching to remove ash and it is most effective for corn stover. Subsequently, leaching test was performed on the finest fraction of crop residues. Canola straw was found to have the best leaching performance compared to wheat straw and corn stover, as it had the highest ash removal efficiency and element removal efficiency (greater than 90% and 50% for K2O and SiO2 respectively). Leaching time of 3 h or 12 h at 25 o C temperature was sufficient for effective ash removal for canola straw, yet longer leaching time of 24 h would improve the ash removal efficiency for corn stover and wheat straw. Leaching temperature had negligible effect on K2O removal efficiency, but significant effect on SiO2 removal efficiency. A preliminary cost analysis indicates that pretreatment by mechanical size fraction followed by water leaching would lead to a 30% increase in the total production cost (TPC) of agro-pellets, whereas the TPC would increase by 66% if the pretreatment is done by water leaching only.
Kim Magrini
National Renewable Energy Laboratory, USA
Title: Upgrading Bionass Fast Pyrolysis Vapors to Hydrocaron Fuels
Biography:
Dr. Magrini is a Principal Research Scientist and Group Manager in the National Bioenergy Center of the National Renewable Energy Laboratory. She currently manages NREL’s Thermochemical Process Development Group, which focuses on the development of catalytic approaches to biofuels production from syngas and pyrolysis. She has more than 25 years of research and management experience in academic, industrial and national laboratory environments and has over 100 peer- reviewed publications, 2 patents, and 130 presentations at national and international meetings. Her research areas include catalyst development for syngas conditioning, hydrogen production, and thermochemical fuels and chemicals production from pyrolysis liquids and vapors.
Abstract:
NREL’s thermochemical biomass conversion research is focused on ex-situ catalytic fast pyrolysis as a potentially efficient and economical route to pyrolysis-based fuel precursors, fuels and chemicals. In this approach, biomass vapors are generated via fast pyrolysis (FP) and destabilizing vapor components (char, inorganics, tar aerosols) are removed by hot gas filtration with the conditioned vapors more amenable to catalytic upgrading via emerging and industrially available zeolites. We use a Davison circulating riser (DCR), a petroleum industry standard, for vapor phase upgrading while a close coupled pyrolyzer system produces consistent pyrolysis vapors as feed to the DCR. Concurrent upgrading catalyst development is focused on identifying and evaluating modifications to ZSM5-based catalysts that increase carbon content of the condensed product while also reducing catalyst coking and increasing deoxygenation activity. Catalyst screening for vapor upgrading showed marked differences in product composition with catalyst type while similar liquid product was obtained with both mixed hardwood and clean pine feedstocks using the same catalyst and process conditions. Ash, aerosols and char removal were additionally quantified for selected experiments. The work presented here will show 1) the impact on product composition from pure vapor upgrading with a suite of catalysts comprising unmodified, and P- and metal-modified zeolites, 2) comprehensive physical and chemical product composition, 3) the impact of catalyst acidity on vapor phase upgrading, and 4) ash and char retention on hot gas filters. Two liters of CFP oil were produced from a modified zeolite. Subsequent hydrotreating produced 48% gasoline and 37% diesel fuels. These results will be discussed and compared with other work conducted in riser systems to produce biomass derived hydrocarbon fuels.
David Medina Cruz
Northeastern University, Chemical Engineering Department (Boston, MA)
Title: Biogenic metallic nanoparticles. From microbiological biofactories to nanometric trojan horses.
Time : 11:40 am
Biography:
David Medina Cruz is a Ph.D. student at Northeastern University who joined the Department of Chemical Engineering in Fall 2017 after a short internship period during his master to develop his thesis about the synthesis of novel nanomaterials using living bacteria. Previously he researched the field of physical-chemistry and nanotechnology, using a nano-based Tessier approach for the environmental remediation of heavy metal-contaminated soils. Besides, he was a member of research focused on the creation of nanostructured filters for the purification of water and air coming from industry, using surfactant-like structures mixed with nanomaterials. He is an active member of American Chemical Society (ACS) and Biomedical Engineering Society (BMES), among others. Additionally, he has supervised several undergraduates and graduates in his research, leading them into the field of Green chemistry, starting a small division of research within Thomas J. Webster’s Nanomedicine Lab, focusing all the effort in the creation and characterization of environmentally-friendly and biological-like approaches for the synthesis of nanomaterial with biomedical applications. Currently, he is an active member of the leadership board of the scientific association ECUSA in the United States.
Abstract:
Antimicrobial resistance to antibiotics (AMR) and cancer and two of the main concerns that the healthcare system should face nowadays. Current drugs and antibiotic treatments are becoming ineffective or have plenty of drawbacks related to misuse and overuse. Therefore, new alternatives are needed, and nanotechnology is rising as a powerful solution over time. How the nanomaterials are created has plenty of influence in their features and applications. Traditional synthesis of nanomaterials, taking knowledge from both physics and chemistry, is subjected to several disadvantages, such as the production of toxic-by-products and harsh conditions, as well as biocompatibility issues. Green nanotechnology is presented as a suitable answer, allowing the generation of nanostructures in a cost-effective and environmentally-friendly approach employing living organisms, such as bacteria, and biomolecules. In this research, pathogenic bacteria (both antibiotic-resistant and standard strains of Gram-negative -such as Escherichia coli- and Gram-positive -such as Staphylococcus aureus-) and human cells (both cancerous -such as human melanoma and glioblastoma cells, and healthy cell lines, such as astrocytes of fibroblasts-) were used for the synthesis of different metallic -gold (Au), palladium (Pd), platinum (Pt), gold-palladium (AuPd) and gold-platinum (AuPt)- and metalloid -selenium (Se)- nanoparticles with sizes between 5 and 120 nm surrounding by an organic-derived coating. Bacteria and human cells were cultured in the presence of metallic salts under standard conditions, allowing the generation of nanoparticles through natural detoxification processes in a synthetic protocol that is followed using microscopy and spectrophotometric techniques. After generation, the entities are purified and extensively characterized in terms of composition, morphology and surface chemistry, through techniques such as Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-Ray Photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Raman spectroscopy, in order to elucidate the complex organic-derived coating surrounding the nanoparticles and the metallic/metalloid core. Nanoparticles were then used as antimicrobial and anticancer agents, with effects characterized through growth curve analysis, MTS experiments and colony counting growing assays, not showing significant cytotoxicity towards healthy human cells. In order to understand the mechanisms or action, Reactive Oxygen Species (ROS) analysis was accomplished as well. The extensive characterization of the nanoparticles showed the presence of organic molecules -such as proteins and lipids- coming from the living organisms, with selenium nanoparticles with sized between 50 and 120 nm. Bacterial tests showed an unusual selective behavior in the antimicrobial effect of bacteria-mediated nanoparticles, showing a dose-dependent inhibition when a bacterial strain X was treated with nanoparticles made by the same bacteria, while poor inhibition was found when different bacteria were used as a target. The nanoparticles showed a robust anticancer effect towards human melanoma and glioblastoma cells while remaining biocompatible towards the healthy cell lines. On the other hand, noble mono- and bimetallic nanoparticles synthesized by human cells, with sized between 5 and 20 nm, were able to inhibit the growth of cell lines in a similar way that nanoparticles made by bacteria showed, with a certain degree of selectivity, remaining biocompatible. Besides, the production of nanomaterials induced a transition of the cells into a named zombie stage'' or suspension toward the cells was not responding to chemical, physical or temporal degradation. Therefore, we demonstrated that microbiological agents are successfully used as a synthetic machines for the generation of different metallic/metalloid nanoparticles of different compositions with biomedical properties. Therefore, they are presented as a suitable approach for the synthesis of nanomaterials in a green fashion, overcoming the limitations of traditional nanotechnology, and opening a new field for drug delivery and smart targeting of cancer and antibiotic-resistant infections.