title: The evolution of the polycrystalline copper surface, first to Cu(111) and then to Cu(100), at a fixed CO₂RR potential: a study by operando EC-STM.
abstract: A study based on operando electrochemical scanning tunneling microscopy (EC-STM) has shown that a polycrystalline Cu electrode held at a fixed negative potential, -0.9 V (vs SHE), in the vicinity of CO2 reduction reactions (CO2RR) in 0.1 M KOH, undergoes stepwise surface reconstruction, first to Cu(111) within 30 min, and then to Cu(100) after another 30 min; no further surface transformations occurred after establishment of the Cu(100) surface. The results may help explain the Cu(100)-like behavior of Cu(pc) in terms of CO2RR product selectivity. They likewise suggest that products exclusive to Cu(100) single-crystal electrodes may be generated through the use of readily available inexpensive polycrystalline Cu electrodes. The study highlights the dynamic nature of heterogeneous electrocatalyst surfaces and also underscores the importance of operando interrogations when structure-composition-reactivity correlations are intended.
authors.affiliation: Joint Center for Artificial Photosynthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Youn-Geun
authors.initials: YG
authors.lastname: Kim
authors.forename: Jack Hess
authors.initials: JH
authors.lastname: Baricuatro
authors.forename: Alnald
authors.initials: A
authors.lastname: Javier
authors.forename: John Mathew
authors.initials: JM
authors.lastname: Gregoire
authors.forename: Manuel P
authors.initials: MP
authors.lastname: Soriaga