(2hb) Programmable, Electrified, and Far-from-Equilibrium Thermochemical Synthesis

Conventional thermochemical reactions operated under near-equilibrium conditions (i.e., continuous heating with a constant temperature of < 1300 K) are unable to accurately tune reaction pathways as they lack rapid, precise and time-resolved control over the temperature profile (i.e., the reaction temperature and timescale). Consequently, many reaction schemes suffer from poor selectivity, low yield, and/or poor catalyst stability. Taking CH₄ conversion as an example, there are limited routes to effectively convert CH₄ to value-added chemicals in a highly efficient and selective manner. This issue is rooted in the aforementioned deficiency of conventional methods, which use continuous heating to manipulate the reaction pathways.

Herein, we report a far-from-equilibrium operating technique (Nature 2022, 605, 470-476; cover) that employs programmable heating and quenching (PHQ) using an electric current, which precisely controls the transient heating time (e.g., 20–110 ms) and provides rapid temperature quenching from up to 2400 K to near room temperature for gas reactants in milliseconds, resulting in high selectivity, energy efficiency, and catalyst stability. Using CH₄ pyrolysis as a model reaction, our catalyst-free PHQ process enables high selectivity to value-added C₂ products (> 75% vs. < 35% by the conventional catalyst-free method, and vs. < 60% by most conventional methods using optimized catalysts) at a significantly lower energy cost (e.g., reduced by > 80%). Our PHQ process added a new dimension of tunability to thermochemical synthesis via the time-resolved temperature profile, which creates a unique opportunity for us to employ active learning to rapidly optimize any target product (e.g., C₂H₄) with much less experimental effort compared to conventional trial and error approaches.

Our PHQ technique can be extended to a broad range of industrially important thermochemical processes. In addition to the homogeneous and endothermic CH₄ pyrolysis reaction, we further demonstrate the utility of PHQ in NH₃ synthesis, which is heterogeneous (catalytic) and exothermic. Under far-from-equilibrium conditions by PHQ, we achieve a stable NH₃ synthesis rate of ~6000 μmol/g_Fe/h under ambient pressure for over 100 h with a non-optimized Fe catalyst. Additionally, we envision our PHQ process, as a new route for improved efficiency in thermochemical synthesis, can be readily coupled with recent material innovations (e.g., state-of-the-art catalysts) for even greater outcomes. In practice, our technique can potentially address some of the most pressing issues in the chemical industry by enabling process intensification and distributed chemical manufacturing using renewable electrical energy.

Research Interests

My research interests focused on thermochemical and electrochemical syntheses, catalysis, and energy conversion and storage. I received my Ph.D. in chemistry at Boston College under the supervision of Dr. Dunwei Wang, where I studied electrochemical energy storage (e.g., metal-air batteries; Chem 2018, Nano Lett. 2018, Angew. Chem. In. Ed. 2016) and conversion (e.g., CO₂ electrochemical reduction, electrochemical polymerization; ACS Cent. Sci. 2018, JACS 2018). I demonstrated the utility of super-concentrated electrolytes in enabling stable Li-air battery operations and for mechanistic studies in CO₂ electrochemical reduction for the first time. During my Postdoc training at the University of Maryland College Park with Dr. Liangbing Hu, my research is divided into three closely related thrusts, including far-from-equilibrium thermochemical synthesis, high-entropy nanoparticle based thermochemical and electrochemical catalysts, and materials recycling and upcycling via process innovations and reactor designs. Electrification (i.e., electrified heating or Joule heating) is the central approach in these research directions, which bridges renewable energy sources to practical use in chemical and materials manufacturing. In detail, I invented an electrified and programmable process that can conduct thermochemical reactions (e.g., CH₄ pyrolysis, NH₃ synthesis) under non-equilibrium conditions toward superior product selectivity and catalyst stability (Nature 2022, cover). In addition, I led the development of a portfolio of electrified heating techniques that can be applied to material synthesis under non-equilibrium (e.g., high-entropy nanoparticle catalysts, solid-state electrolytes, bulk metals and cermets, carbon fibers, and thin film coatings; Science 2022, Adv. Mater. 2022/2021/2020, Matter 2022, Mater. Today 2020). Furthermore, I discovered several new routes to recycle electrochemical devices (Joule 2020) and plastic wastes (Nature, under review), as well as to upcycle biomass such as lignin to value-added chemical feedstock. In the future, I plan to keep working in the field of energy and sustainability. The overarching objective of my research is to find solutions to the urgent energy, environment, and sustainability challenges through novel chemical process development and material innovations.

Teaching Interests

I always have a strong passion for teaching and mentoring, because I can share my knowledge to the next-generation researchers and engineers, meanwhile often get inspired with new ideas and fresh perspectives. I have two years of teaching experience during my graduate study in China, where I gave lectures to undergraduate students on Polymer Chemistry. I served as a Teaching Assistant for two years during my Ph.D. at Boston College, where I taught both lab and discussion sessions of Analytical Chemistry (junior level) and Advanced Methods (honor program and senior level) for the Chemistry Department. I am one of the most favorite Teaching Assistants in the department and many of my previous students are still in contact with me via social media, sometimes asking me for career or research advices. My past research experience is highly interdisciplinary, which provides me a strong basis for future teaching tasks. I was trained as a chemist, and had rich research experience in materials science and chemical engineering. My research topics covers fundamental physical science and practical aspects in energy, catalysis, environment, sustainability and other applications. Taking advantage of my background and expertise, I would like to develop courses along three directions, including advanced manufacturing with renewable energy, sustainable material solutions for energy and environmental crisis, and materials recycling and upcycling. In addition to teaching, I am an extremely experienced mentor in research. During my Postdoc training, I supervised 10 Ph.D. candidates and visiting scholars in their research projects, which led to 16 publications in prestigious journals such as Adv. Mater., Sci. Adv., and Matter, etc. This training prepared me with extensive experiences and skills as a future Principal Investigator and have taught me how to work collaboratively and grow together with the students.

Image Description/Caption

Highlights of Dr. Qi Dong’s research achievements