(6dt) Organic Molecular Electrocatalysts for Energy-Water Applications

Los Alamos National Laboratory, Materials Physics & Applications,
Los Alamos, New Mexico 87545

Phone: (505) 667-3238; Fax: (505) 665-4292; E-mail: xiyin@lanl.gov; xiyinuiuc@gmail.com
Personal website: https://sites.google.com/view/xiyin

Expertise

(i) Materials chemistry, coordination chemistry, and inorganic chemistry; (ii) molecular simulation and computational modeling; (iii) physical chemistry, electrochemistry, and electrocatalysis; (iv) organic molecular electrocatalysis; (v) energy conversion and storage, polymer electrolyte fuel cells.

Education

• Ph.D., Chemical Engineering (advisor: Prof. Hong Yang), University of Illinois at Urbana-Champaign
• M.Sc., Materials Science, University of Rochester
• M.Sc. and B.Sc., Materials Science and Engineering, Tsinghua University

Employment

• Postdoctoral Research Associate (mentor: Dr. Piotr Zelenay), Los Alamos National Laboratory, Los Alamos, NM (2015-present)

Proposal Writing Experience

• “Organic molecular electrocatalysts for hydrogen evolution reaction” to LANL Laboratory Directed Research and Development, Exploratory Research (LDRD-ER), Co-PI, 2018 (funded, $ 990K for three years)
• “Metal-free molecular catalysts for hydrogen evolution reaction” to LANL Laboratory Directed Research and Development, Exploratory Research (LDRD-ER), Co-PI, 2017
• “A new class of metalorganic structure containing infinite one­-dimensional metal chain” to National Science Foundation, draft, 2013

Awards & Honors

• MRS Graduate Student Award Silver Medalist, Materials Research Society (2015)
• SCS Science Image Challenge Finalist, UIUC School of Chemical Science (2014)

Journal Reviewer

• Nano Energy, Nano Letters, Carbon, Fuel Cells, ACS Applied Materials & Interfaces, Journal of Materials Chemistry A, Journal of Electroanalytical Chemistry, Nanotechnology, The Journal of Physical Chemistry, Journal of Nanoparticle Research, etc.

Summary of Previous Works

Throughout my research, I have sought to combine experimental studies with computational modeling and theory to accelerate discoveries that will have extensive impact on society. My dissertation work at the University of Illinois at Urbana-Champaign focused on a fundamental understanding of the nucleation and growth of metal nanocrystals for catalysis. Different from most observation-based studies, my work emphasized the chemistry of metal-ligand complexation during pre-nucleation and designed ligand environments to tune nucleation and growth via thermodynamic and kinetic leverages. By employing density functional theory (DFT) calculations and reaction kinetic models, I developed new theories on nonclassical nanocrystal growth. These works led to the world’s first atomically thin palladium nanosheets and a quantitative understanding of the roles of surfactant ligands in nanocrystal synthesis for electrocatalysis, gas sensing, and biological applications.

My postdoctoral work at Los Alamos National Laboratory has focused on the development of platinum group metal-free (PGM-free) catalysts for fuel cell cathodes, driven by the need to replace scarce and expensive PGM materials with compounds based on earth-abundant elements, such as C, N, Fe, and other transition metals. Through molecular-level design of catalyst templates, kinetic study of catalyst degradation, and optimization of the electrode structure, my work has covered a broad spectrum of fuel cell research to boost the performance of state-of-the-art PGM-free catalysts.

While expanding my research portfolio from precious metal-based materials to carbon-based electrocatalysts, I noticed that most electrocatalysts are built on metal-centered active sites that have been electronically modified via metallic, ionic, or covalent bonds. The activity improvement of conventional catalysts may intrinsically be limited by the possible electronic structures of these metal sites. To overcome this limitation, I conceived of an idea to use organic molecules as metal-free electrocatalysts, which are attractive due to their highly tailorable geometry, tunable electronic structures, and chemical robustness. With these factors in mind, I designed and modeled a metal-free N-containing molecule as a bifunctional catalyst for H₂O₂ production and thehydrogen evolution reaction. This discovery is the first demonstration of high catalytic activity from an inexpensive, small organic molecule in a practical polymer electrolyte membrane (PEM) device for crucial electrochemical reactions. Building upon these findings, I plan to establish a world-leading program that aims to develop an entirely new class of electrocatalysts based on rationally designed organic molecules for clean energy and environmental applications, which goes beyond conventional electrocatalysts that rely on precious metal or transition metal elements.

Research Interests:

My future research aims to unravel the structure-activity relationships in novel Organic Molecular Electrocatalysts (OMECs) and apply that fundamental knowledge to the molecular-level design of next-generation electrocatalysts for renewable energy and environmental applications. Different from conventional metal-containing electrocatalysts, OMECs are solely based on the earth abundant non-metal elements, e.g., C, N, H, etc. The covalent bonding in organic structures ensures the robustness of OMECs in harsh electrochemical environment. The highly-tailorable structures of OMECs will allow the tuning of electrochemical functions in a large organic chemical space. Although millions of organic compounds have been designed and synthesized, no systematic works have been done to fully explore the electrocatalytic activities of the metal-free organic molecules.

My proposed research will encompass three main thrust areas: (1) distributed electrochemical production of hydrogen peroxide (H₂O₂) for water treatment; (2) electrochemical hydrogen production and energy storage; and (3) carbon dioxide (CO₂) reduction into high-value liquid fuel. The first thrust aims to address the increasing need for distributed on-site production of H₂O₂ as a water disinfection agent for use in remote areas and disaster mitigation during the disruption of regular infrastructure services. The second and third trusts will provide solutions for the integration of hydrogen facilities with smart grids, as well as the production of clean fuels.

Teaching Interests:

My research background is in chemical engineering and materials science, with expertise in electrochemistry, materials chemistry and computational modeling. My research experience allows me to confidently teach the following courses:

• Thermodynamics of Chemical Processes
• Electrochemical Engineering and Fuel Cell
• Electrochemistry
• Computational Design of Energy Materials
• Fundamentals of Materials Science and Engineering
• Reaction Kinetics
• Synthetic Nanomaterials
• Materials Chemistry

Publications

1. X. Yin, L. Lin, H. T. Chung, U. Martinez, A. Baker, S. Maurya, P. Zelenay, “Organic molecular electrocatalyst for hydrogen evolution reaction in acidic polymer electrolyte”, Science, 2018, under review.
2. X. Yin, P. Zelenay, “Kinetic models for the degradation mechanism of PGM-free ORR catalysts”, ECS Transactions, 2018, 85, accepted.
3. (Front Cover) X. Yin, M. Shi, K. S. Kwok, D. L. Gray, J. A. Bertke, H. Yang, “Dish-like higher-ordered nanostructures of palladium through metal ion-ligand complexation”, Nano Research, 2018, 11, 3442–3452
4. X. Yin, M. Shi, J. Wu, D. L. Gray, J. A. Bertke, H. Yang, “Quantitative analysis of different formation modes of platinum nanocrystals controlled by ligand chemistry”, Nano Letters, 2017, 17 (10), 6146–6150
5. X. Yin, L. Lin, H. T. Chung, S. K. Babu, U. Martinez, G. M. Purdy, P. Zelenay, “Effects of MEA fabrication and ionomer composition on fuel cell performance of PGM-free ORR catalyst”, ECS Transactions, 2017, 77 (11), 1273–1281
6. J. Kim, P.-C. Shih, K.-C. Tsao, Y.-T. Pan, X. Yin, C. J. Sun, H. Yang, “High-performance pyrochlore-type yttrium ruthenate electrocatalyst for oxygen evolution reaction in acidic media”, Journal of the American Chemical Society, 2017, 139 (34), 12076–12083
7. Y.-T. Pan, J. Wu, X. Yin, H. Yang, “In situ ETEM study of composition redistribution in Pt-Ni octahedral catalysts for electrochemical reduction of oxygen”, AIChE Journal, 2016, 62 (2), 399–407
8. (Front Cover) X. Yin, J. Wu, P. P. Li, J., H. Yang, “Self-heating approach to the fast production of uniform metal nanotructures”, ChemNanoMat, 2016, 2 (1), 37–41
9. X. Yin, X. H. Liu, Y.-T. Pan, K. A. Walsh, H. Yang, “Hanoi tower-like multilayered ultrathin palladium nanosheets”, Nano Letters, 2014, 14 (12), 7188–7194
10. X. Yin, S. A. Warren, Y.-T. Pan, K.-C. Tsao, D. L. Gray, J. Bertke, H. Yang, “A new motif for infinite metal atom wires”, Angewandte Chemie International Edition, 2014, 53 (51), 14087–14091
11. Y.-T. Pan*, X. Yin*, K. S. Kwok, H. Yang, “Higher-ordered nanostructures of flexible palladium two-dimensional nanosheets for fast hydrogen sensing”, Nano Letters, 2014, 14 (10), 5953–5959 (*Equal contributors.)
12. J. Kim, X. Yin, K.-C. Tsao, S. Fang, H. Yang, “Ca₂Mn₂O₅ as oxygen-deficient perovskite electrocatalyst for oxygen evolution reaction”, Journal of the American Chemical Society, 2014, 136 (42), 14646–14649
13. J. Wu*, M. Shi*, X. Yin, H. Yang, “Enhanced oxidation reduction stability of (111) surface dominant Pt₃Ni@Pt₃Pd core-shell nanoparticle catalysts”, ChemSusChem, 2013, 6 (10), 1888–1892 (*Equal contributors.)
14. J. Wu, P. Li, Y.-T. Pan, S. Warren, X. Yin, H. Yang, “Surface lattice-engineered bimetallic nanoparticles and their catalytic properties”, Chemical Society Reviews, 2012, 41, 8066–8074
15. X. Yin, K. X. Chen, H. P. Zhou, X. S. Ning, “Combustion synthesis of Ti₃SiC₂/TiC composites from elemental powders under high gravity conditions”, Journal of the American Ceramic Society, 2010, 93 (8), 2182–2187.
16. X. Yin, K. X. Chen, H. P. Zhou, X. S. Ning, “Combustion synthesis of Ti₃SiC₂ from Ti/Si/C powders under high gravity conditions”, Rare Metal Materials and Engineering, 2008, 37 (9), 1606–1609.

Conference Presentations

1. (Invited) X. Yin, U. Martinez, S. Komini Babu, H. T. Chung, G. M. Purdy, P. Zelenay, “Kinetic insight into the degradation mechanism of PGM-free ORR catalysts”, 233rd ECS Meeting, Seattle, WA, 2018
2. X. Yin, L. Lin, H. T. Chung, U. Martinez, A. Baker, S. Maurya, P. Zelenay, “Organic molecular catalyst for hydrogen evolution reaction”, 232nd ECS Meeting, National Harbor, MD, 2017
3. X. Yin, L. Lin, U Martinez, H. T. Chung, P. Zelenay, “Organic molecular catalyst for electrochemical production of hydrogen peroxide”, 232nd ECS Meeting, National Harbor, MD, 2017
4. X. Yin, L. Lin, H. T. Chung, S. Komini Babu, U Martinez, G. M. Purdy, P. Zelenay, “Effects of porosity and ionomer composition on fuel cell performance of PGM-free ORR catalysts”, 231st ECS Meeting, New Orleans, LA, 2017
5. X. Yin, H. T. Chung, U. Martinez, L. Lin, P. Zelenay, “Magnetic purification of PGM-free catalysts”, PRiME 2016/230th ECS Meeting, Honolulu, HI, 2016
6. X. Yin, H. T. Chung, U. Martinez, J. H. Dumont, G. M. Purdy, P. Zelenay, “Non-PGM ORR catalysts prepared from polyaniline-type polymers with strong affinity to iron”, 229th ECS Meeting, San Diego, CA, 2016
7. X. Yin, J. Wu, Y.-T. Pan, H. Yang, “Quantitative analysis of kinetically controlled growth of metal nanoparticles based on ligand-metal ion interactions”, 2015 MRS Spring Meeting, San Francisco, CA, 2015
8. X. Yin, X. Liu, Y.-T. Pan, K. Walsh, H. Yang, “Hanoi tower-like multilayered 2D Pd nanosheets and the molecular level understanding of the formation mechanisms”, 2015 MRS Spring Meeting, San Francisco, CA, 2015
9. X. Yin, J. Wu, P. Li, H. Yang, “Formation of nanoparticles in self-regulated reaction systems”, 246th ACS National Meeting, Indianapolis, IN, 2013
10. X. Yin, J. Wu, W. Zhou, H. Yang, “Development of facet-controlled Pt and Pt alloy nanocatalysts for oxygen reduction reaction”, 246th ACS National Meeting, Indianapolis, IN, 2013