October 23, 2025
Varanasi Sai Subhankar, an aerospace engineering Ph.D. student advised by Thomas Underwood, received the Student Excellence Award at the 2025 American Physical Society Gaseous Electronics Conference (GEC). According to Underwood, this is the highest honor a student can receive in the field of plasma science.
Subhankar was selected for his paper “Plasma Activated Co-reactants Enable Liquid Fuel Selectivity Control in CH4-CO2 Conversion Across Metal-Adsorbate Binding Regimes,” which is based on a research article recently submitted to Nature Catalysis, and is currently under review. He was selected as a winner from a group of five finalists. Learn more about his work and why it matters:
Tell us about your research and why it matters.
Our research focuses on developing cleaner and more efficient ways to convert two greenhouse gases, methane (CH4) and carbon dioxide (CO2), into valuable liquid fuels and chemicals. Conventional thermal catalytic processes require extremely high temperatures and pressures, making them energy-intensive and environmentally costly. A further challenge comes from the scaling laws that govern catalysis – the strength with which a surface binds reacting molecules is directly linked to how easily those molecules transform. Improving one step in the reaction often makes another less favorable, and as a result, many catalysts tend to over-oxidize desirable products like methanol into carbon monoxide before they can be extracted.
To overcome these challenges, we use non-thermal plasmas, which generate short bursts of energetic electrons that can activate CH₄ and CO₂ at much lower temperatures. Yet even in these conditions, we found the reaction often slows down over time because unwanted carbon or oxygen atoms accumulate on the catalyst surface, blocking active sites and stopping the chemistry. We discovered that introducing a targeted co-reactant (such as hydrogen) that becomes excited in the plasma can continuously remove these surface poisons and restore catalytic activity. This self-regenerating process allows us to independently tune reaction pathways, selectively producing fuels like methanol and ethane under mild conditions. Our approach provides a new framework for converting greenhouse gases into sustainable fuels using renewable sources of energy. This method can be used to rethink how energy can be stored, converted, and transported more sustainably worldwide.
What are some practical applications of this work?
In many current industrial settings, streams that contain methane and carbon dioxide, such as those from natural gas processing, landfills and refineries, are flared or vented. This practice releases unutilized hydrocarbons into the atmosphere. Converting these gases directly into liquid fuels or platform chemicals such as methanol, ethanol or acetic acid provides a promising pathway for carbon utilization. These oxygenate molecules are energy dense, easy to store and transport, and compatible with today’s fuel and chemical infrastructure.
Our plasma enabled process can be used in several ways. It can capture methane from biogas or flare sites and convert it into methanol at the source. It can also use carbon dioxide rich exhaust from cement or steel plants to make feedstocks for sustainable aviation fuels. In addition, plasma reactors powered by renewable electricity can produce carbon neutral fuels when solar or wind energy is abundant. In the long term, this approach can enable distributed and decentralized fuel production that turns waste greenhouse gases into valuable resources while reducing emissions across many industries.
How did you feel when you received this award?
I felt incredibly honored and grateful to have our work recognized by the plasma science community.
Learn more about the innovative work taking place in the Underwood Lab.
