posted on 2024-01-03, 09:04authored byRileigh Casebolt DiDomenico, Kelsey Levine, Colin Bundschu, Laila Reimanis, Tomas Arias, Tobias Hanrath
We explore dynamic electrocatalysis
by pulsing the applied
potential
to modulate the temporal microenvironment during the electrochemical
reduction of CO2. We focus on copper electrodes by virtue
of their unique ability to bind *CO intermediates and enable C–C
coupling to form high-value C2 products, such as ethylene
or ethanol. We examine the well-known competition between *CO and
*H for active sites, as their relative coverage is crucial for enhancing
the formation of C2 products. We found that pulsing the
applied potential can significantly enhance the electrocatalytic activity
of C–C coupling, increasing the turnover frequency of C2 products by up to 33-fold compared to potentiostatic electrolysis.
We interpret this improvement in the context of oscillating surface
coverage and the transient dynamics of the *CO/*H coverage during
the cathodic pulse. Through a combination of experimental and computational
methods, we investigate how pulse frequency influences the turnover
frequency of CO2 to C2 products on Cu. Our study
not only validates recent theoretical predictions about the potential
of dynamic (electro)catalysis to surpass the limitations imposed by
the Sabatier limit but also uncovers scientific and mechanistic insights
into dynamic processes within the electrical double layer. These insights
are instrumental in formulating design principles for pulsed CO2 electrolysis with enhanced C2 activity. The outcomes
of this study lay a foundational framework for future advances in
programmable CO2 electrolysis with improved activity, selectivity,
and durability.