Tracking the Potential-Controlled Synthesis of Cu-Nanocuboids and Graphene-Covered Cu-Nanocuboids Under Operando CO2 Electroreduction

<p>The electroreduction of CO₂(CO₂RR) is a promising strategy towards sustainable fuels. Cu is the only earth-abundant catalyst capable of CO₂-to-hydrocarbons conversion; yet, its dynamic structure under <i>operando</i> CO₂RR conditions remains unknown. Here, we track the Cu structure <i>operando</i> by electrochemical scanning tunneling microscopy and Raman spectroscopy. Surprisingly, polycrystalline Cu surfaces reconstruct forming Cu nanocuboids whose size can be controlled by the polarization potential and the time employed in their <i>in-situ</i> synthesis, without the assistance of organic surfactants and-or halide anions. If the Cu-surface is covered by a graphene monolayer, smaller features with enhanced catalytic activity for CO₂RR can be prepared. The graphene protecting layer soften the 3D morphological changes that Cu-based catalysts suffer when exposed to aggressive electrochemical environments, and allows us to track the kinetic roughening process. This novel strategy is promising for improving Cu long-term stability and, consequently, controlling product selectivity.</p>

Tracking the Potential-Controlled Synthesis of Cu-Nanocuboids and Graphene-Covered Cu-Nanocuboids Under Operando CO2 Electroreduction

<p>The electroreduction of CO₂(CO₂RR) is a promising strategy towards sustainable fuels. Cu is the only earth-abundant catalyst capable of CO₂-to-hydrocarbons conversion; yet, its dynamic structure under <i>operando</i> CO₂RR conditions remains unknown. Here, we track the Cu structure <i>operando</i> by electrochemical scanning tunneling microscopy and Raman spectroscopy. Surprisingly, polycrystalline Cu surfaces reconstruct forming Cu nanocuboids whose size can be controlled by the polarization potential and the time employed in their <i>in-situ</i> synthesis, without the assistance of organic surfactants and-or halide anions. If the Cu-surface is covered by a graphene monolayer, smaller features with enhanced catalytic activity for CO₂RR can be prepared. The graphene protecting layer soften the 3D morphological changes that Cu-based catalysts suffer when exposed to aggressive electrochemical environments, and allows us to track the kinetic roughening process. This novel strategy is promising for improving Cu long-term stability and, consequently, controlling product selectivity.</p>