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US-Israeli Symposium on C1 Chemistry :
08:00am - 09:30am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Aditya Bhan, Organizer, Univ of Minnesota; Oz M Gazit, Organizer, Technion; Prof. Dmitri Gelman, Organizer, The Hebrew University of Jerusalem; Daniel Resasco, Organizer, University of Oklahoma; Daniel Resasco, Presider, University of Oklahoma; Aditya Bhan, Presider, Univ of Minnesota
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Division/Committee: [CATL] Division of Catalysis Science & Technology

This symposium explores the topic of C1 conversion in context of the broader chemical enterprise. Presentations will feature research at the state-of-the-art in electrochemical and thermochemical upgrading of C1 species to fuels and chemicals.

Sunday
Catalytic activation of light alkanes on promoted molybdenum oxide catalysts: Coupling of catalytic rates and their mechanistic implications
08:00am - 08:30am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Catalytic conversions of light alkanes to their corresponding olefins are attractive routes for utilizing natural gas feedstocks. Starting with ethane, its reaction produces ethylene as the platform molecule for sequential synthesis of a wide variety of commodity chemicals, including polyethylene, styrene, ethylene oxide, and ethylene glycol. Its catalytic turnovers occur either without a co-oxidant via dehydrogenation or with O2 or CO2 via oxidative dehydrogenation reactions. Herein, we will unravel the mechanistic similarities and differences among the various ethane conversion reactions, on two-dimensional MoOx dispersed on Al2O3 catalysts promoted by Fe, Co, or Ni catalysts. These reactions, irrespective of the presence of or the chemical identity of the co-reactant, occur via the common step, that the initial C-H bond activation of ethane limits rates. The ethane activation cycle is catalytically coupled with the oxidant activation cycle, the latter generates reactive oxygen species that scavenge the surface carbon debris and therefore retain the catalytic reactivity and stability. We will discuss these catalytic cycles among the different ethane conversion catalysis, the key catalytic events, and their periodic reactivity trends, when incorporating the earth abundant Fe, Co, and Ni transition metal into the dispersed MoOx structures. More specifically, we will discuss how these metal cations could alter the catalytic rates of the various, concomitant catalytic cycles, interjecting deactivation, leading to the observed rates and selectivities. We attempt to provide consolidate mechanistic framework, accounting for both the rates as well as the time-dependent rate decay for ethane reactions for the series of catalyst materials.
Sunday
Multi-phase catalysts for stable methane cracking and reforming
08:30am - 09:00am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Prof. Brian A. Rosen, Presenter, Tel Aviv University
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Defective solid-catalysts and multi-phase catalysts are intriguing materials which would pave the way towards stable methane cracking and reforming. While point defects have been well studied in energy conversion ceramics by exploiting non-isovalent lattice substitutions and non-stoichiometric compounds, the impact of multidimensional defects on catalytic activity and stability is far less studied. During activation, energy conversion catalysts often go through solid-state phase transitions. These transitions can either be beneficial or detrimental to performance. We observe that extended defects critically impacts the temperature at which such phase transitions can occur, the pathway of the phase transition, and resulting catalytic activity and stability of the catalyst. Extended defects such as stacking faults in substituted lanthanum nickelates and lanthanum ferrates can be exploited to significantly extend catalyst lifetimes and lower apparent activation energy for critical reactions such as methane and carbon monoxide oxidation. Furthermore, multi-phase catalysts involving solid-liquid equilibrium are also exploited to imbue stable methane cracking with increased performance.
Sunday
Elucidating and controlling the selective electrocatalytic reduction of CO2 to C1 chemical intermediates
09:00am - 09:30am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Matthew Neurock, Presenter
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
The development of sustainable strategies to meet the world’s increasing energy demands will require the use of renewable energy sources together with carbon-neutral and energy efficient processes that can significantly reduce CO2 emissions. The sustainable catalytic conversion of CO2 to carbon monoxide as well as formic acid and their subsequent transformation to fuels and chemical intermediates offer attractive routes to carbon-neutral fuels. Nature readily carries out these reactions out with very high selectivities by co-locating the active metal centers within highly reactive reaction cavities. Recent experimental results show that the CO2 can be efficiently reduced over various late transition metals within ionic liquid as well as within alkaline media. The metal-electrolyte-solvent interface plays a critical role in enhanced the CO2 reduction and selectively forming either CO or formic acid produces.
Novel potential-dependent ab initio molecular dynamics simulations are carried out herein to help unravel the elementary steps and the mechanisms that govern these transformations and to show how changes in the solvent, electrolyte, pH and potential drive the activity as well as the selectivity in these systems. We show how changes in the potential and the reaction conditions can drive the formation of unique electrolyte, solvent, reactant environments that readily facilitate the rate controlling electron transfer reaction and selectively guide the subsequent proton addition to exclusively form CO or formic acid products. The simulations combined with experiments show that subtle changes in the electrolyte and the solvent can be used to dictate the formation of CO or formic acid with Faradaic Efficiencies of > 97 %. The simulations are used to help identify important electrolyte and metal catalysts systems as well as mixed electrolyte systems that will drive the active and selective formation to C1 products.

Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
08:00am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
CO2 hydrogenation to hydrocarbons over heterogeneous catalysts
08:00am - 08:40am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Society is faced with a CO2 dilemma – we need to slow our production of the gas while simultaneously developing efficient methods to capture, store and/or use it. My group has focused on CO2 capture for over a decade, designing porous materials and processes for CO2 separation from different gas mixtures, including flue gases and ambient air. More recently, we have focused our attention on the conversion of CO2 to useful products, such as hydrocarbons.
In this presentation, I will briefly describe some of the key approaches to CO2 capture, followed by a more detailed description of two approaches for CO2 conversion being explored in my group, (i) a chemical looping pathway based on high temperature CO2 capture coupled with in-situ hydrogenation of the captured CO2 to produce methane or methanol, and (ii) conversion of dilute CO2 into aromatics via a process intensification approach pairing methanol synthesis and zeolite catalysis. The performance of these (i) alkali-promoted supported metal and (ii) mixed metal oxide / zeolite hybrid catalysts will be described.

Sunday
Cesium-promoted ethanol production from CO2 hydrogenation on Cu/ZnO(000) surface: Full mechanistic study
08:40am - 09:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Dr Xuelong Wang, Presenter, Brookhaven National Laboratory; Pedro Ramírez; Dr Jose A Rodriguez, PhD, Chemistry Department; Ping Liu, Brookhaven National Laboratory
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Efficient conversions of CO2 into value-added chemicals such as alcohols are of great industrial and scientific interest. The Cu/ZnO/Al2O3 catalyst has been extensively studied and commercialized in the industry to produce C1 alcohol, methanol from CO2 hydrogenation. In contrast, for Cu-based catalysts, successful attempts to achieve the production of higher alcohols, such as ethanol, which is safer and offers higher energy density, are very limited, due to the difficulty in C-C bond coupling and thus low selectivity. Most Cu-based catalysts are active for the reverse water gas shift (RWGS) reaction and hydrogenation of CO rather; while the C-O bond activation is difficult, which hinders C-C bond formation. Promoters such as Fe have been reported previously, which can facilitate C-O bond dissociation over Cu catalysts. In addition, alkali metal promoters, including K and Cs, have also shown the capability of C chain growth over Cu-based catalysts. Yet, the reaction mechanism remains elusive.
Here, combining surface science experiments and DFT calculations, we present a detailed mechanistic understanding of the roles that Cs plays in ethanol production at the Cu-Cs-ZnO interface under CO2 hydrogenation condition. Our study not only leads to the discovery of new pathways for ethanol production from CO2 hydrogenation but also opens new possibilities to allow the highly active and selective CO2 conversion to higher alcohols on widely used and low-cost Cu-based catalysts.

Sunday
Development of a zero gap membrane electrode assembly carbon monoxide electrolyzer
09:00am - 09:20am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Carbon monoxide electroreduction is a rapidly developing field for the production of valuable chemicals. When coupled with CO2 capture and electrochemical conversion, it can be used as a clean CO2 negative process for the production of a variety of products. Carbon monoxide reduction has the distinct advantage over direct electrochemical CO2 reduction to multi-carbon products (C2+) in that it does not suffer from carbonate formation, allowing for higher feed conversion and electrolyte stability. This work focuses on the design and production of a zero gap membrane electrode assembly carbon monoxide electrolyzer which operates at low cell potentials (< 2.5 V) and industrially relevant current densities (> 300 mA/cm2) for the production of acetate and ethylene. Zero gap electrolyzers place the cathode and anode in direct contact with a conductive polymer membrane. This provides distinct advantages over conventionally studied three-compartment flow cell designs, where the cathode is in contact with an aqueous liquid electrolyte. Specifically, the use of a solid polymer membranes increases cell stability while decreasing the electrolyzer internal resistance. We demonstrate the high selectivity of the device for producing acetate and ethylene, achieving high Faradaic efficiencies as well as high molar production rates relative to other C2+ products. The system was also found to have improved current densities and cell voltages when compared to conventional three-compartment carbon monoxide electroreduction systems. The opportunity for products to be shuttled through the membrane, however, leads to a more complicated system when compared to three-compartment systems, where the products are solely captured in the catholyte. An investigation was therefore performed to determine both the anode’s as well as the membrane’s effects on the system’s product output and performance.
Sunday
Withdrawn
09:20am - 09:40am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person

Sunday
Efficient inteplay of ZrO2 and Ni0 for photocatalytic CO2 conversion into mehtane monitored using 13CO2 and EXAFS
09:40am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The reaction mechanism of CO2 photoreduction into methane was elucidated by the time-course monitoring of the mass chromatogram, in situ Fourier transform infrared (FTIR) spectroscopy, and in situ extended X-ray absorption fine structure (EXAFS). Under13CO2, H2, and UV–visible light, 13CH4 was formed at a rate of 0.98 mmol h−1 gcat−1using Ni (10 wt%)–ZrO2 that was effective at 96 kPa. Under UV–visible light irradiation, the 13CO2 exchange reaction and FTIR identified physisorbed/chemisorbed bicarbonate and the reduction because of charge separation in/on ZrO2, followed by the transfer of formate and CO onto the Ni surface (Scheme 1). EXAFS confirmed exclusive presence of Ni0 sites. Then, FTIR spectroscopy detected methyl species on Ni0, which was reversibly heated to 394 K owing to the heat converted from light based on the analysis of Debye-Waller factor changes obtained by EXAFS. Heat reactions were much slower (Figure 1). Using D2O and H2, H/D ratio in the formed methane was in agreement with H/D ratio in reactant. This study paves the way for using first row transition metals for solar fuel generation and on-site fuel supply on planets using only UV–visible light.
<b>Scheme 1.</b> Proposed intermediate species during CO<sub>2</sub> exchange and photocatalytic CO<sub>2</sub> reduction.

Scheme 1. Proposed intermediate species during CO2 exchange and photocatalytic CO2 reduction.

<b>Figure 1. </b>Time course of <sup>13</sup>CH<sub>4</sub> and <sup>12</sup>CH<sub>4</sub> formation during the catalytic test exposed to (A) <sup>13</sup>CO<sub>2</sub> (2.3 kPa), H<sub>2</sub>O (2.3 kPa), and H<sub>2</sub> (21.7 kPa) under UV-visible light and (B) at 393 K, under dark (first 24 h) followed by under UV-visible light (6 h) both using Ni (10 wt%)-ZrO<sub>2</sub>-Reduced (0.020 g).

Figure 1. Time course of 13CH4 and 12CH4 formation during the catalytic test exposed to (A) 13CO2 (2.3 kPa), H2O (2.3 kPa), and H2 (21.7 kPa) under UV-visible light and (B) at 393 K, under dark (first 24 h) followed by under UV-visible light (6 h) both using Ni (10 wt%)-ZrO2-Reduced (0.020 g).


Disinfection Byproducts in Drinking Water & Wastewater: Detection, Formation & Control:
08:00am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B401
Susan Richardson, Organizer; Chii Shang, Organizer, The Hong Kong University of Sci. Technol.; Paul Westerhoff, Organizer, Presider, Arizona State Univ; Prof. Xin Yang, Organizer, Sun Yat-sen University, Environmental Science
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
Co-sponsor/Theme: Theme: Sustainability
Division/Committee: [ENVR] Division of Environmental Chemistry

This symposium will focus on the identification of emerging DBPs, the latest advances in the underlying chemistry of DBPs formation and technologies in eliminating DBP risks in water and wastewater treatment.

Sunday
Introductory Remarks
08:00am - 08:05am USA / Canada - Eastern - August 22, 2021 | Room: B401
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid

Sunday
Revisiting bromine incorporation during chlorination of drinking water
08:05am - 08:35am USA / Canada - Eastern - August 22, 2021 | Room: B401
David Reckhow, Presenter, Univ of Massachusetts
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
The important role of bromide in disinfection byproduct formation has been recognized since the very earliest publications on DBPs in drinking water. Subsequent developments such as recognition that brominated DBPs may be more toxic than their chlorinated analogues, increases in bromide levels in some raw drinking waters, and the likelihood of a new HAA9 standard have elevated the interest in predicting bromine DBP speciation. In this talk, I will summarize and attempt to integrate new information on factors affecting bromine incorporation, with special focus on reaction kinetics. Some of these data come from recent work at UMass by graduate and undergraduate students, and some from other research groups around the world. Our current knowledge of bromine incorporation into DBPs starts with basic kinetics and mechanism of reactions with model compounds. This information can be combined with current ideas on natural organic matter constituents, occurrence of bromide in raw waters, and water system operation to gain a better understanding of DBP speciation. Ultimately, better mathematical models are key tools that will help to manage exposure to the more toxic brominated DBPs.
Sunday
Establishing formation potential test conditions for assessing haloacetonitrile precursors in source waters
08:35am - 08:55am USA / Canada - Eastern - August 22, 2021 | Room: B401
Amit Gajurel; Kazi Haider; David Reckhow, Univ of Massachusetts; Eric Dickenson; Dr. Erica Marti, Presenter, University of Nevada, Las Vegas
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
Haloacetonitriles (HANs) are nitrogenous disinfection byproducts (DBPs) that are formed during free chlorine (Cl2) or chloramine (CLM) disinfection of water. Despite being detected frequently in different water sources and showing a higher order of cytotoxicity and genotoxicity as compared to their regulated counterparts, only a few studies have been conducted to determine relative sources of HAN precursors in source waters. DBP precursors are often assessed through formation potential (FP) testing, although the conditions (pH, Cl2/CLM dose, time) vary among DBP and type of test (e.g., uniform formation condition). HANs are known to undergo hydrolysis, with increasing hydrolysis rate as pH and number of halogen atoms increases. In addition, HAN stability is affected by chlorine residual, with increasing residual leading to a shorter half-life. Therefore, it is important to tailor formation potential conditions for HANs. Formation potential tests with free chlorine and preformed monochloramine were conducted with non-disinfected wastewater effluent at two pHs (7 and 8), three Cl2/CLM doses, and five reaction times (i.e., 0.5, 1, 2, 3 and 5 days). After the designated reaction time, samples were extracted and analyzed by gas chromatography mass spectrometry for 10 HANs. As expected, HAN FP concentrations were higher at pH 7 compared to pH 8, and chlorination produced higher HAN FP as compared to chloramination. Concentrations of dichloroacetonitrile and bromochloroacetonitrile were greatest, indicating greater stability and/or preferred formation from precursors. It was observed that trihalogenated, monochlorinated, and iodinated HANs (trichloroacetonitrile, monochloroacetonitrile, and monoiodoacetonitrile) had low yields under all experimental conditions. This can be attributed to the lack of precursors and/or greater hydrolysis in the case of trihalogenated HANs. In general a higher disinfection dose at pH 7 resulted in maximum formation for most compounds; however, reaction time had varying effects on final concentration with some HANs continually increasing while other HANs peaked and decreased with time.
Sunday
Benzalkonium chloride is present in wastewater influent and is biotransformed to the potent N-nitrosodimethylamine precursor benzyldimethylamine during secondary treatment
08:55am - 09:15am USA / Canada - Eastern - August 22, 2021 | Room: B401
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
N-nitrosodimethylamine (NDMA) is a probable human carcinogen and lifetime consumption of 0.7 ng/L is associated with a 10-6 lifetime cancer risk. NDMA forms through reactions between organic N precursors and chloramines, added to was as a disinfectant. Although some NDMA precursors are well known (e.g., ranitidine, methadone, dimethylamine), the full mass balance on precursors and NDMA formation is not yet closed. This research focused on the formation of NDMA from benzalkonium chloride (BAC), a surfactant that is present in detergents, disinfectants (particularly those used in surface cleaning) and thus in wastewater. Benzalkonium chloride was not previously thought to be an important NDMA precursor because it contains relatively unreactive quaternary N, but recent research has shown that aerobic heterotrophs cleave the alkyl chain at the N, resulting in benzyldimethylamine (BDMA), a well-known and highly potent NDMA precursor. We selectively cultured BAC consuming microorganisms and showed that the NDMA yield of the dissolved biotransformation products was ~85x times greater than the BAC. Measurements of BAC and BDMA in wastewater treatment plants across unit processes indicated that BAC is an important source of NDMA forming reactive N in wastewater. NDMA yield of the products peaked rapidly (hours) and declined over days indicating that the biotransformation product BDMA is further degraded to less reactive N and longer HRTs may somewhat decrease the NDMA FP of wastewater effluent.
Sunday
Effects of intermittent water supply and point-of-use disinfection with chlorocyanurates on DBP formation and exposure risk in low-income communities
09:15am - 09:35am USA / Canada - Eastern - August 22, 2021 | Room: B401
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
Disinfection research in low-income communities (here defined as low-income countries and low-income communities in middle-income countries) around the world has strongly prioritized pathogen inactivation, and rightly so. However, as disinfection becomes widely practiced in low-income communities, chronic health risks from exposure to disinfection byproducts (DBPs) are likely to increase. Factors affecting DBP formation that are specific to low-income settings remain poorly characterized due to a paucity of research as well as over-reliance on trihalomethanes (THMs) as an indicator. The objective of this research is to investigate the impacts of intermittent water supply and point-of-use (POU) disinfection practices on DBP formation through a field study in Dhaka, Bangladesh accompanied by bench-scale experiments. A concern of intermittent supply is that variation in distribution system pressure allows for intrusion of uncontrolled sewage and contaminated stormwater. This problem may be acute in areas such as Dhaka that experience extreme flooding. We conducted sampling campaigns in residential neighborhoods during the dry and rainy seasons. Using artificial sweeteners as a signal of wastewater intrusion, we identified a potential relationship of intrusion with increased formation of nitrogen-containing (N-DBP) classes at the tap. These water systems did not practice centralized disinfection; however, a separate study had installed disinfectant dosers on storage tanks of apartment buildings in the study area. These dosers delivered chlorocyanurates, an alternative chlorine disinfectant popular for POU applications (as well as swimming pools and cleaning products). We measured DBP formation in these systems and conducted bench-scale experiments to compare chlorocyanurates with chlorine bleach. Although chlorocyanurates reduced THM concentrations by ~10-20% relative to bleach in some cases, they promoted the formation of more toxic N-DBPs, Br-DBPs and I-DBPs. The mechanisms of these reactions are further investigated with controlled experiments. These findings have important implications for over 1 billion people served by intermittent water supplies, and for the many communities where centralized disinfection is not reliably practiced. In addition, the results highlight the need for more research on chlorocyanurate chemistry due to their widespread usage and recent implementation by several water systems in the US.
Sunday
Formation of N-nitrosoglyphosate from glyphosate and nitrite at neutral pH and occurrence in recycled wastewater
09:35am - 09:55am USA / Canada - Eastern - August 22, 2021 | Room: B401
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid
Glyphosate is the most commonly used herbicide in the U.S. Roughly 250 million pounds are applied each year in the U.S. with more than 3.5 billion pounds being applied since 1974. During the same time, more than 19 billion pounds have been applied globally. The International Agency for Research on Cancer (IARC) classifies glyphosate as a Group 1A carcinogen and it has an MCL of 0.7 mg/L in drinking water under EPA’s Safe Drinking Water Act. Its nitrosated analogue, N-nitrosoglyphosate (NNG), can occur in commercial glyphosate preparations as a byproduct and can form in soils where glyphosate is present at low pH (<6). Toxicity of NNG has not been evaluated by EPA due to the low reported prevalence as a byproduct in commercial formulations of glyphosate. The aim of this study was to determine whether NNG could form at conditions relevant to drinking water treatment where glyphosate may be present as a contaminant, or where glyphosate and nitrite may be present as co-contaminants due to agricultural runoff, and to determine whether NNG was present in advanced treated recycled water. We hypothesized that disinfection with monochloramine, and disinfection with free chlorine in the presence of nitrite, would lead to NNG formation from glyphosate. NNG was formed in the mg/L range upon the reaction of glyphosate with nitrite-N above 2 mg/L and at glyphosate concentrations above 100 mg/L at pH 8 in three days, and the initial NNG production rate was 0.384 ppb/min at 20 mg/L of nitrite-N and 100 mg/L of glyphosate. The presence of monochloramine or free chlorine did not greatly impact the yield of NNG in the presence of nitrite. However, greater concentrations of nitrite resulted in greater concentrations of NNG. In formation potential tests utilizing monochloramine and glyphosate at pH 8, NNG did not form in the absence of nitrite indicating the reaction is nitrite-dependent. At a detection limit of 0.5 mg/L, NNG was not detected in advanced treated recycled water or secondary wastewater effluent. Because N-nitrosamines typically occur at the ng/L concentration in potable waters, future work is aimed at reducing the method detection limit, determining occurrence in agricultural run-off, recycled wastewater for agricultural irrigation and conventionally-treated drinking water and determining the influence of other water quality parameters on the formation of NNG.
Sunday
Concluding Remarks
09:55am - 10:00am USA / Canada - Eastern - August 22, 2021 | Room: B401
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Hybrid

US-Israeli Symposium on C1 Chemistry :
10:30am - 12:00pm USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Aditya Bhan, Organizer, Univ of Minnesota; Oz M Gazit, Organizer, Technion; Prof. Dmitri Gelman, Organizer, The Hebrew University of Jerusalem; Daniel Resasco, Organizer, University of Oklahoma; Aditya Bhan, Presider, Univ of Minnesota
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Division/Committee: [CATL] Division of Catalysis Science & Technology

This symposium explores the topic of C1 conversion in context of the broader chemical enterprise. Presentations will feature research at the state-of-the-art in electrochemical and thermochemical upgrading of C1 species to fuels and chemicals.

Sunday
Effect of surface phase oxides on Ni catalyzed methane dry reforming
10:30am - 11:00am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Anup Tathod; Jin Wang; Oz M Gazit, Presenter, Technion
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Under reducing conditions, a strongly interacting reducible support can hinder the sintering of a nickel (Ni) nano-particle but, may also lead to severely reduced catalyst activity due to overcoating of the Ni by the support (i.e. SMSI). In contrast, Ni supported on a weakly interacting non-reducible support will have lower thermal stability but, can show higher activity. We find that the level of these metal support interactions (MSI) can be balanced using a mediating layer of surface phase thin oxides (SPO) in the form of MgAl mixed oxide nano-platelets (MO). We show that this approach can be practically implemented to balance between the benefits of the strong MSI of the SPO and the weak MSI of the underlying support (SiO2, ZrO2). Testing this approach for methane dry reforming (MDR) we found that the presence of 0.5-2.5 %wt Ni on the SPO, which is dispersed on an underlying ZrO2 surface, enhances the catalytic activity by ~15 fold, as compared to Ni supported on bulk MO. To better understand and control the nature of these interaction we performed extensive HAADF-STEM-EDS and XPS analyses. Planer model catalysts are analyzed using atomic force microscopy (AFM) to study the effect of the underlying support on the Ni and on the exposed surface of the SPO. Obtained information related to surface adhesion, surface potential and surface friction forces of the MO-NSs are correlated to catalyst performance and the mechanism by which the Ni is promoted by the presence of the SPO.
Sunday
Mechanism and surface species for formic acid decomposition on dispersed copper nanoparticles
11:00am - 11:30am USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Mechanistic details of HCOOH dehydrogenation routes on Cu nanoparticles are relevant to C1 chemistries that involve formate-type species as intermediates or spectators, such as water-gas shift and methanol synthesis. It has been widely accepted that HCOOH decomposes unimolecularly on transition metal surfaces via bidentate formate (*HCOO*) intermediate, with its C-H activation kinetically limiting the overall rates. Although such route is relevant during temperature-programmed surface reactions (TPSR) of pre-adsorbed *HCOO* species, bimolecular routes may be prevalent at catalytic conditions when HCOOH(g) coexists with *HCOO*. This study seeks to clarify and update our understanding of HCOOH dehydrogenation routes on Cu nanoparticles by combining kinetic, isotopic, and spectroscopic experiments with density functional theory (DFT) calculations.

At practical conditions (0.1-3.5 kPa HCOOH; 473-503 K), Cu surfaces are covered with *HCOO* species, which reach their saturation at 0.25 monolayer (ML) (*HCOO*/Cusurface=0.25) because of strong repulsion among bound *HCOO* species. HCOOH(g) binds molecularly at the interstices (denoted as ' sites; HCOOH') within such saturated *HCOO* adlayers; such interstices become saturated with HCOOH' upon formation of another 0.25 ML adlayer, with HCOOH' species forming strong H-bonds with vicinal *HCOO*. Measured rates reflect the bimolecular decomposition of the HCOOH'-*HCOO* complex, in which either HCOOH' or *HCOO* can lead to the formation of the CO2 product, while the other one re-forms the *HCOO* adlayer. These two bimolecular routes cannot be distinguished from kinetic data, isotopic effects, or infrared spectra or accessible to TPSR studies. DFT-derived barriers are slightly larger for the route that forms CO2 from HCOOH' than for the one forming CO2 from *HCOO* (ΔHact = 83 vs. 68 kJ mol-1).

These bimolecular routes are consistent with all experimental and theoretical data. This work, in turn, provides a compelling example of how repulsive interactions among bound species restricts their coverages to < 1 ML, thus allowing residual interstices in such “passivated” surfaces to bind intermediates less strongly, thus allowing them to react or to increase the reactivity of the bound species in the more refractory template.

Sunday
Multifunctional pincer complexes possessing a secondary coordination sphere as catalysts for CO2 hydrogenation
11:30am - 12:00pm USA / Canada - Eastern - August 22, 2021 | Room: B216 - B217
Prof. Dmitri Gelman, Presenter, The Hebrew University of Jerusalem
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - Hybrid
Burning fossil fuels worldwide has led to an increasing CO2 concentration in the atmosphere to such a large extent that global climate change caused by greenhouse gases has become a major ecological challenge. At present, its amount can be reduced by either capture and storage or by chemical conversion and utilization. There is no doubt that carbon dioxide storage is a cheaper solution and that it is useful for reducing CO2 emissions quickly. Unfortunately, it does not solve the accumulation problem in the long term, whereas converting CO2 into carbon-containing value-added products and feedstock does.
The catalytic conversion of CO2/H2/CO to methanol is already being performed on an industrial scale. Other products, such as formic acid and its derivatives, can be synthesized by carbon dioxide hydrogenation. However, despite this progress, we are still far from the point where carbon dioxide becomes a concrete player in the sustainable chemistry/energy market. Significant steps should be taken toward developing more efficient catalysts for CO2 conversion processes, as well as developing new reaction schemes that allow for more efficient utilization of carbon dioxide in fine and bulk synthesis.
The talk is devoted to designing ligand-metal cooperative catalytic systems for the dehydrogenation of formic acid and hydrogenation of CO2. Our studies revolve around a family of 3-dimensional PC(sp3)P pincer complexes developed by our group. The synthetic approach leading to all these examples is straightforward and represents a modular and divergent approach to a variety of 3-dimensional platforms equipped with custom-tailored primary and secondary coordination spheres. In particular, we address the cooperative activation and functionalization of carbon dioxide by bifunctional catalysts possessing transition metals in the primary coordination sphere and a pendant Lewis acidic functionality in the secondary sphere.

Advances in Renewable Materials:
10:30am - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Glenn Larkin, Organizer, Michigan Technological University; Falk Wolfgang Liebner, Organizer, Boku University Vienna; Amir Sheikhi, Organizer, Penn State University; Glenn Larkin, Presider, Michigan Technological University; Amir Sheikhi, Presider, Penn State University
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid
Division/Committee: [CELL] Division of Cellulose and Renewable Materials

General Oral Session for the Division of Cellulose and Renewable Materials

Sunday
Introductory Remarks
10:30am - 10:35am USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid

Sunday
Towards a new understanding of the retro-aldol reaction for oxidative conversion of lignin to aromatic aldehydes and acids
10:35am - 11:00am USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid
Lignin is the most abundant natural bio-polymer after cellulose and accounts for 30% of non-fossil carbon on earth. The retro-aldol reaction is one of the key steps involved in the oxidative conversion of lignin to aromatic aldehydes and acids. In principle, the retro-aldol reaction can proceed in the absence of oxygen. In this work, a new approach based on the influence of oxygen on the oxidation of lignin was investigated. The effect of reaction chemistry, time, temperature, and lignin feedstock play a key role on the yield of aromatic aldehydes and acids. At 140°C, oxidation of softwood Lignoboost kraft lignin for 40 minutes results in combined maximum yield of 5.17% w/w of vanillin and vanillic acid. In comparison, using the new approach in which oxygen was charged for only 20 minutes during the 40 minute reaction improved this yield considerably to 6.95%. Further, yield improvement was obtained when applying this approach to different lignin feedstocks. Oxidation also increased the carboxyl content of lignin from 0.49 mmol/g to 1.41 mmol/g which represents consequential improvement. The current study provides further evidence showing that the oxidation reaction is a crucial pathway for lignin valorization.
Sunday
Photocatalytic rejuvenation enabled self-sanitizing, reusable, and biodegradable masks against COVID-19
11:00am - 11:25am USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Hongli Zhu, Presenter
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid
Personal protective equipment (PPE) has been highly recommended by the U.S. Centers for Disease Control and Prevention (CDC) for self-protection under the disastrous SARS-CoV-2 (COVID-19) pandemic. Nevertheless, the massive utilization of PPE, especially the N95 respirators and sing-use masks, encounters significant challenges in recycling and sterilizing the used masks. To tackle the environmental pollution of currently used masks made of synthetic plastic, in this work, we designed a reusable, biodegradable, and antibacterial mask. The mask was prepared by electrospinning of polyvinyl alcohol (PVA), poly(ethylene oxide) (PEO), and cellulose nanofiber (CNF), and with subsequent esterification and then deposition of nitrogen-doped TiO2 (N-TiO2) and TiO2 mixture. The fabricated mask containing photocatalytic N-TiO2/ TiO2 can reach 100% bacteria disinfection under either light source (200-2500 nm, 106 Wm-2) as 0.1 sun simulation or natural sunlight for only 10 min. Thus, the used mask can be rejuvenated through light irradiation and reused, which represents one of the handiest technologies for handling used masks. Furthermore, the intermolecular interactions between PVA, PEO and CNF enhanced electrospinnability and the mechanical performance of the resultant mask. The obtained masks possess superior mechanical strength (10-fold elastic modulus and 2-fold tensile strength higher than a commercial single use mask). The comprised electrospun nanofibers with porous structures in between as well as strong electrostatic attraction enabled breathability (83.4 L min-1 of air flow rate) and superior particle filterability (98.7 %). The prepared mask also had excellent cycling performance, wearability, and stable filtration efficiency even after 120 min wearing. Therefore, this novel mask could be a great alternative to current masks to addressing the urgent need for sustainable, reusable, environmentally friendly, and efficient personal protection designs under the ongoing COVID-19 contagion.
Sunday
Withdrawn
11:25am - 11:50am USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid

Sunday
Free-radical polymerization of bio-based monomers
11:50am - 12:15pm USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Maryam Mousa, Presenter; Eva Malmstrom, KTH Royal Institute of Technology; Anna Larsson Kron; Helena Bergenudd
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid
The demand to produce materials from non-fossil based sources, i.e. bio-based raw materials, is increasing due to environmental concerns and limited resources. Bio-based building blocks result in new materials with sometimes unprecedented properties rendering them an interesting subject to study.
Two of these building blocks are the itaconic acid-derived α-methylene-γ-butyrolactone and the structurally similar α-methylene-γ-valerolactone which can be synthesized from the bio-based levulinic acid. Itaconic acid is a promising platform chemical that is produced by the fermentation of carbohydrates and it was listed by the U.S. Department of Energy as one of the top-value added chemicals from biomass. In this study, we report the free-radical polymerization of these two lactones into homopolymers or together with fossil-based (meth)acrylate monomers, methyl acrylate and methyl methacrylate in different ratios. 2,2′-Azobisisobutyronitrile or lauroyl peroxide were used as initiators to investigate their effect on the polymerization behaviors. Polymerizations were monitored by monomer conversion, and the final polymers were characterized with respect to molecular weight, composition, glass transition temperature and thermal degradation. The incorporation of the monomers in the copolymers was significantly affected by the differences in reactivity ratios, sometimes to such an extent that the polymers exhibited a substantial compositional drift as corroborated by assessed thermal properties.
Increased thermal stability and tailored Tg’s were achieved by copolymerizing the lactones and the (meth)acrylates in different ratios, making the lactones interesting building blocks for synthesis of bio-based or partially bio-based materials.

Sunday
Panel Discussion
12:15pm - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B406b - B407
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Hybrid