Understanding the selectivity and mechanisms of the hydroxyl radical-mediated electrochemical methane oxidation reaction toward reduced methane pollution

Methane is a reactive gas that can degrade air quality. Facilities such as wastewater treatment plants routinely generate methane, and its release can affect nearby communities. Current management practices often burn or flare methane. This project will study an electrochemical methane oxidation reaction (eMOR). The reaction converts methane into methanol, a liquid chemical. The research will develop advanced materials to study methane reactions. It will also identify reaction pathways and operating conditions that favor formation of useful products. The results will guide the development of future methane conversion technologies. These eMOR technologies could be integrated with industrial biotechnologies. They may also support advanced manufacturing with more efficient use of resources. The project will also link research and education through undergraduate and graduate curriculum development, student research training, and outreach to K–12 learners. These activities will help prepare the future STEM workforce. This project will investigate mechanisms and kinetics of eMOR using heterostructured electrocatalyst materials that target a new reactive oxygen species (ROS) mediated C–H bond activation pathway. Electroanalytical measurements, including cyclic voltammetry, chronoamperometry, and controlled electrolysis, will be combined with quantitative product analysis to determine methane conversion, liquid product selectivity, and competing oxidation reactions as functions of overpotential, catalyst composition, and electrolyte hydraulic retention time. Inspired by semi-conducting materials, experiments will first evaluate methane activation using conductive diamond electrodes to assess the role of electro-generated hydroxyl radicals. The project will then examine composite conductive diamond-metal oxide catalysts to determine how transition-metal oxide co-catalysts influence oxidation pathways and suppress methane overoxidation. Complementary quantum-based density functional theory modeling will evaluate interfacial interactions and reaction energetics on the electrocatalyst interfaces to elucidate the underlying reaction mechanisms. Additionally, integration of experimental observations with microkinetic analysis will establish fundamental relationships among ROS formation, catalyst structure, C–H bond activation, and product distribution. The resulting mechanistic understanding will advance fundamental knowledge of selective methane oxidation using ROS-mediated reactions and provide new catalyst design principles and operating boundaries for eMOR. As a result, this interdisciplinary project will provide new generalizable knowledge of methane oxidation and C-H bond activation that can benefit related environmental chemistry, while opening the door to future methane valorization technologies that reduce pollution, recover value from waste streams, and improve the well-being of individuals in society. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2532908 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Joshua Jack | Institution: Regents of the University of Michigan - Ann Arbor, ANN ARBOR, MI | Award Amount: $418,576 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2532908 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2532908.html