Electrolytic abatement of gas contaminants on gas diffusion electrodes

Semiconductor manufacturing relies on a wide range of fluorinated process gases whose exceptional chemical stability enables highly selective plasma etching and chamber-cleaning operations. However, a fraction of these compounds leaves the fabrication process unreacted and is discharged through facility exhaust systems. Among them, perfluorinated compounds such as carbon tetrafluoride (CF₄) are particularly problematic because of their extreme chemical inertness, long atmospheric lifetimes, and high global warming potential. More broadly, fluorinated gases belong to the wider family of PFAS-related substances that are increasingly recognized as persistent environmental contaminants and have become a major focus of international regulatory and industrial sustainability efforts. Existing treatment technologies, including wet scrubbing, thermal destruction, and plasma-based abatement, can require substantial energy input, specialized infrastructure, or chemical consumables, while their effectiveness may be limited for the most stable fluorinated molecules. The development of electrified, energy-efficient remediation technologies therefore represents an important scientific and industrial challenge.

This PhD project will investigate the electrocatalytic conversion of hard-to-abate gaseous contaminants, initially focusing on CF₄ as a model compound. Building on recent advances in reductive CF₄ activation, including the demonstration of room-temperature remediation using electrogenerated Co(I) species [1], the project will evaluate molecular catalysts capable of activating highly fluorinated molecules under electrochemical conditions. These catalysts will be immobilized onto gas diffusion electrodes (GDEs), leveraging ongoing developments in gas-fed electrochemical reactor technologies that provide efficient gas transport, high catalyst utilization, and scalable operation. The influence of catalyst structure, electrode architecture, electrolyte composition, and operating conditions on conversion efficiency, reaction pathways, product selectivity, and long-term stability will be systematically investigated.

Subsequently, the most promising catalytic systems will be integrated into a complete electrochemical reactor through the development of membrane-electrode assemblies, including the selection of suitable ion-conducting membranes, cathodes, and electrolyte environments. The resulting devices will be benchmarked under controlled laboratory conditions and evaluated using simulated fab-like exhaust streams representative of semiconductor manufacturing emissions. Beyond the immediate challenge of CF₄ abatement, the project seeks to establish fundamental design principles for the electrochemical conversion of contaminants in the gas phase. The outcomes could contribute to more sustainable semiconductor manufacturing, provide new technological opportunities for PFAS-related remediation, and advance the scientific understanding of electrocatalytic activation mechanisms for some of the most persistent compounds currently released into the environment.