What is the role of Nafion in the electroreduction of CO₂ into ethylene

Doctor Daniel Curulla-Ferre

D. Un Lee, D. R. Oh , J. M. Jenny, T. F. Jaramillo,

TotalEnergies OneTech Belgium, TotalEnergies S.E.;SUNCAT Center for Interface Science and

Catalysis, Department of Chemical Engineering, Stanford University

Abstract: The electroreduction of CO₂ into added-value products has been studied extensively in the past few years. Gas difussion electrodes (GDE) are prepared using several components; carbon is used to enhance electron transport across the GDE, copper is generally used as an active metal for the electroreduction of CO₂, PTFE is used to avoid flooding and Nafion® is found in all GDE formulations to enhance the concentration of protons in the vicinity of the catalytic center. In the paper, we deep-dive in the role of each component and optimise the formulation of the GDE. We found that the presence of Nafion® decreases the

performance of CO₂ reduction into ethylene and that those materials formulated without Nafion® yield the highest Faraday efficiency to ethylene. The best result we have obtained with Cu as single-metal active component is 37% Faraday efficiency to ethylene. We have also observed that those electrocatalysts formulated without Nafion® increase the production of liquid products, and that the presence of Nafion® just utilises this excedent of current density that is captured in the formation of liquid products to dramatically enhance the evolution of hydrogen at the electrocatalyst. From a more fundamental point of view, we also found that the evolution of ethylene at the electrode is not correlated with that of carbon monoxide, which

questions the accepted mechanistic path in which ethylene is formed by coupling of two CO molecules. Of course, the macroscopic analysis of the performance of the electrocatalyst does not necessarily exclude such elementary step at microscopic level.

Hydrogen

Faraday efficiency versus the total sum of Faraday efficiencies of gas

products classified by content of Nafion® in the formulation of the GDE.

Biography: Daniel Curulla holds a degree in Chemistry (1996) and a PhD in Chemistry (2001) from the University Rovira i Virgili in Spain. He began his career as a research associate at the Technical University of Eindhoven in the Netherlands, where he worked from 2001 to 2007. In 2008, he joined TotalEnergies in Paris, France, as a research project

manager. Since 2013, he has been part of TotalEnergies' research center for catalysis and polymers. Currently, Daniel is a senior scientist specializing in catalysis and a senior specialist in machine learning and design of experiments. He is responsible for transforming R&D into a

data-centric activity. His research spans various fields of catalysis and polymers, including the development of Fischer-Tropsch catalysts, catalysts for CO2 conversion into methanol, membranes for CO2 purification, membrane reactors for propane dehydrogenation, electrocatalysts for CO2 conversion into chemicals, mechanical recycling of plastics, feed evaluation in pyrolysis, and the development of design of experiments and machine learning algorithms for catalysis and polymer research. Daniel has published over 90 peer-reviewed scientific papers and is a co-inventor on more than 20 patent families. In addition to his work in chemistry, he holds a degree in software engineering from the Universitat Oberta de Catalunya and is currently completing a master's degree in data science at the same university.

He has also received training in life cycle analysis, project management, and innovation management. Throughout his career, Daniel has collaborated with prestigious universities such as ETH Zurich, Stanford University, the University of Amsterdam, Utrecht University, and Bayreuth University.