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Heterogeneous Catalysis for Organic Reactions

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This honors thesis is focused on two separate catalysis projects conducted under the mentorship of Dr. Javier Pérez-Ramírez at ETH Zürich. The first project explored ethylene oxychlorination over supported europium oxychloride catalysts. The second project investigated alkyne semihydrogenation over nickel

This honors thesis is focused on two separate catalysis projects conducted under the mentorship of Dr. Javier Pérez-Ramírez at ETH Zürich. The first project explored ethylene oxychlorination over supported europium oxychloride catalysts. The second project investigated alkyne semihydrogenation over nickel phosphide catalysts. This work is the subject of a publication of which I am a co-author, as cited below.

Project 1 Abstract: Ethylene Oxychlorination
The current two-step process for the industrial process of vinyl chloride production involves CuCl2 catalyzed ethylene oxychlorination to ethylene dichloride followed by thermal cracking of the latter to vinyl chloride. To date, no industrial application of a one-step process is available. To close this gap, this work evaluates a wide range of self-prepared supported CeO2 and EuOCl catalysts for one-step production of vinyl chloride from ethylene in a fixed-bed reactor at 623 773 K and 1 bar using feed ratios of C2H4:HCl:O2:Ar:He = 3:3 6:1.5 6:3:82 89.5. Among all studied systems, CeO2/ZrO2 and CeO2/Zeolite MS show the highest activity but suffer from severe combustion of ethylene, forming COx, while 20 wt.% EuOCl/γ-Al2O3 leads to the best vinyl chloride selectivity of 87% at 15.6% C2H4 conversion with complete suppression of CO2 formation and only 4% selectivity to CO conversion for over 100 h on stream. Characterization by XRD and EDX mapping reveals that much of the Eu is present in non-active phases such as Al2Eu or EuAl4, indicating that alternative synthesis methods could be employed to better utilize the metal. A linear relationship between conversion and metal loading is found for this catalyst, indicating that always part of the used Eu is available as EuOCl, while the rest forms inactive europium aluminate species. Zeolite-supported EuOCl slightly outperforms EuOCl/γ Al2O3 in terms of total yield, but is prone to significant coking and is unstable. Even though a lot of Eu seems locked in inactive species on EuOCl/γ Al2O3, these results indicate possible savings of nearly 16,000 USD per kg of catalyst compared to a bulk EuOCl catalyst. These very promising findings constitute a crucial step for process intensification of polyvinyl chloride production and exploring the potential of supported EuOCl catalysts in industrially-relevant reactions.

Project 2 Abstract: Alkyne Semihydrogenation
Despite strongly suffering from poor noble metal utilization and a highly toxic selectivity modifier (Pb), the archetypal catalyst applied for the three-phase alkyne semihydrogenation, the Pb-doped Pd/CaCO3 (Lindlar catalyst), is still being utilized at industrial level. Inspired by the very recent strategies involving the modification of Pd with p-block elements (i.e., S), this work extrapolates the concept by preparing crystalline metal phosphides with controlled stoichiometry. To develop an affordable and environmentally-friendly alternative to traditional hydrogenation catalysts, nickel, a metal belonging to the same group as Pd and capable of splitting molecular hydrogen has been selected. Herein, a simple two-step synthesis procedure involving nontoxic precursors was used to synthesize bulk nickel phosphides with different stoichiometries (Ni2P, Ni5P4, and Ni12P5) by controlling the P:Ni ratios. To uncover structural and surface features, this catalyst family is characterized with an array of methods including X-ray diffraction (XRD), 31P magic-angle nuclear magnetic resonance (MAS-NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Bulk-sensitive techniques prove the successful preparation of pure phases while XPS analysis unravels the facile passivation occurring at the NixPy surface that persists even after reductive treatment. To assess the characteristic surface fingerprints of these materials, Ar sputtering was carried out at different penetration depths, reveling the presence of Ni+ and P-species. Continuous-flow three-phase hydrogenations of short-chain acetylenic compounds display that the oxidized layer covering the surface is reduced under reaction conditions, as evidenced by the induction period before reaching the steady state performance. To assess the impact of the phosphidation treatment on catalytic performance, the catalysts were benchmarked against a commercial Ni/SiO2-Al2O3 sample. While Ni/SiO2-Al2O3 presents very low selectivity to the alkene (the selectivity is about 10% at full conversion) attributed to the well-known tendency of naked nickel nanoparticles to form hydrides, the performance of nickel phosphides is highly selective and independent of P:Ni ratio. In line with previous findings on PdxS, kinetic tests indicate the occurrence of a dual-site mechanism where the alkyne and hydrogen do not compete for the same site.

This work is the subject of a publication of which I am a co-author, as cited below.

D. Albani; K. Karajovic; B. Tata; Q. Li; S. Mitchell; N. López; J. Pérez-Ramírez. Ensemble Design in Nickel Phosphide Catalysts for Alkyne Semi-Hydrogenation. ChemCatChem 2019. doi.org/10.1002/cctc.201801430

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2019-05

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Does Inclusivity Really Matter? The Importance of Diversity and Inclusion in Farm-Based Internship Programs

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Current farming demographics in the United States indicate an aging and overwhelmingly white group of farmers, stimulating the need for engaging a younger and more diverse population. There is an opportunity to engage these populations through farm-based internship and apprenticeshi

Current farming demographics in the United States indicate an aging and overwhelmingly white group of farmers, stimulating the need for engaging a younger and more diverse population. There is an opportunity to engage these populations through farm-based internship and apprenticeship programs, which are immersive programs on small-scale, sustainable farms. These programs are unique in providing hands-on training, housing, meals, and a stipend in return for labor, presenting a pathway to social empowerment. The potential outcomes of increasing diversity and inclusion in farm programs are absent from the research on the benefits of diversity and inclusion in other work environments, such as the corporate setting. This paper presents the results of a study aimed at determining levels of diversity and inclusion in United States farm-based internship programs, and the viability of these programs as an effective opportunity to engage marginalized young people in farming. The study of 13 farm owners and managers across the U.S. found that the participants are focused on fostering education and training, environmental benefits, and a sense of community in their respective programs. All participants either want to establish, or believe they currently have, an inclusive workplace on their farm, but also indicated a barrier to inclusivity in the lack of a diverse applicant pool. Future recommendations for removing that barrier and involving more young, diverse interns include increased outreach and access to these programs, the use of inclusive language, and further research.

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2017-05

Feed Your Senses

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Feed Your Senses is an illustrated book made to holistically communicate links between local food systems and cultural wellbeing. Food was the center of my household growing up; my mom’s love of food, cooking, and experimenting with flavors molded my

Feed Your Senses is an illustrated book made to holistically communicate links between local food systems and cultural wellbeing. Food was the center of my household growing up; my mom’s love of food, cooking, and experimenting with flavors molded my palette from a young age. As I got older, I realized that everyone has a deeply personal relationship with their food - no matter what their upbringing. My developing interests in food took off when I started traveling and experiencing the uniqueness and vibrancy of food culture. Food became the object of every trip I took.

The summer after my Junior year, I studied abroad in Denmark and was given the opportunity to create my own research topic. My interest in Sustainability has always revolved around food, so I started thinking about ways that I could incorporate this interest with the geographical backdrop of Århus, Denmark. Food is a medium for so many uniquely human creations: celebrations, art, connection, and taste. Food is also a big driver of climate change, as the meat and agriculture industries account for more than half of all greenhouse gas emissions. However, I wanted to research more than food. I wanted to incorporate balance; a balance of local and global food systems, a balance of individual and community relationships, and a balance of science and art. I wanted to show how food is a driving force in achieving global sustainability and resilience.

After much contemplation, I began researching the connections between local food and community wellbeing in the city. I interviewed farm-to-table chefs, local farmers, farmer’s market vendors, street food vendors, and consumers on their relationships with food. The topic itself was flexible and open-ended enough so that each interviewee could relate it to their lives in a unique way. I loved the research so much that I decided to continue interviewing stakeholders in the Phoenix metropolitan area. Through the continuation of my research in Arizona, I was able to include a comparative element that offered a better perspective on the matter. I found that the history of the country itself has a significant influence on people’s mindsets and actions surrounding food and the environment. The common theme I heard from all interviewees, however, was their confidence in the power of food to unite people to one another and to the natural world.

I chose to create this illustrated book because my research experience was a whole and inseparable experience; it could never be fully expressed in words. I wanted my project to be an intellectual and visual map of my journey, inspiring the reader to go on a journey of their own. Therefore, I partnered with an undergraduate art student at Arizona State University, Sofia Reyes, to help create my vision. I shared my experiences, photos, and stories with her so that she could create the beautiful watercolor paintings that make the book so visually appealing and accessible to all demographics. The images act as a way of engaging all of our human senses, initiating a stronger connection to the material presented.

Creating this project was my favorite experience as an undergraduate, and I feel fortunate to be able to tell the stories of those intimately tied to the local food system. I am in the process of entering my book in various competitions including Writer’s Digest, Reader’s Favorites, The Food Sustainability Media Award, and The Indie Book Awards. I am also going on to publish the book through a small publishing company.

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2018-05

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Farms of the Future: Food Security in a Changing World

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The purpose of this thesis is to imagine and predict the ways in which humans will utilize technology to feed the world population in the 21st century, in spite of significant challenges we have not faced before. This project will

The purpose of this thesis is to imagine and predict the ways in which humans will utilize technology to feed the world population in the 21st century, in spite of significant challenges we have not faced before. This project will first thoroughly identify and explain the most pressing challenges the future will bring in climate change and population growth; both projected to worsen as time goes on. To guide the prediction of how technology will impact the 21st century, a theoretical framework will be established, based upon the green revolution of the 20th century. The theoretical framework will summarize this important historical event, and analyze current thought concerning the socio-economic impacts of the agricultural technologies introduced during this time. Special attention will be paid to the unequal disbursement of benefits of this green revolution, and particularly how it affected small rural farmers. Analysis of the technologies introduced during the green revolution will be used to predict how 21st century technologies will further shape the agricultural sector. Then, the world’s current food crisis will be compared to the crisis that preceded the green revolution. A “second green revolution” is predicted, and the agricultural/economic impact of these advances is theorized based upon analysis of farming advances in the 20th century.

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2019-05

Local Food Sustainability Engagement for ASU Tempe Students

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Local food sustainability has gained significant recent attention over the past decade. Considerable research points to a host of economic, social, and environmental benefits resulting from engagement with local food systems. These benefits are more apparent when contrasted with a

Local food sustainability has gained significant recent attention over the past decade. Considerable research points to a host of economic, social, and environmental benefits resulting from engagement with local food systems. These benefits are more apparent when contrasted with a model in which individuals participate in larger, non-local food systems for all or most of their food sourcing. As such, this project was designed to explore possible barriers, such as lack of awareness, to engagement in local foods among Arizona State University (ASU) students on the main Tempe campus. Furthermore, this creative project aimed to evaluate how a local foods program conducted in a university dining hall might impact students’ awareness and interest in local foods served on site.

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2019-05

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Utilizing Best Practices and Behavioral Science to Increase the Effectiveness of University Residential Community Composting Program

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Solutions to mitigating the negative externalities of climate change are deemed necessary for a sustainable future. Residential community composting, such as the Community Compost Program at Vista del Sol, could potentially play an important role within Arizona State University’s (ASU)

Solutions to mitigating the negative externalities of climate change are deemed necessary for a sustainable future. Residential community composting, such as the Community Compost Program at Vista del Sol, could potentially play an important role within Arizona State University’s (ASU) solution to develop a sustainable institution as programs aspire to develop sustainable behaviors and integrate environmentally positive practices within students’ lives. The research and review of how universities can utilize a residential community compost program to ignite sustainable action within on-campus communities could present helpful information for additional universities to implement on their own. This review will aim to tackle the research question: how can the operational functions of existing university residential composting programs and behavioral science research be implemented within the Community Compost Program at Arizona State University? The review from existing university residential composting programs and behavioral sciences will be completed to provide an explanation of how residential community composting can overall be effectively prompted.

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2020-05