Cations Responsible for Varied CO<sub>2</sub>RR Product Selectivity at High Overpotentials over Cu<sub>2</sub>O Nanocubes
Saeede Tafazoli, Azra Şekercioğlu, Hamaneh Zarenezhad, Başak Ataş, Amin Mohammadpour, Timuçin Balkan, Sarp Kaya
Abstract
High Resolution Image Download MS PowerPoint Slide This study investigates the role of cations in tuning the structure and chemical state of Cu 2 O nanocubes during CO 2 reduction reactions (CO 2 RR) and how these changes impact product selectivity. Different cations (Li +, K +, Cs + ) in carbonate ( CO 3 2 − ) electrolytes have a significant effect on the dissolution and reprecipitation of Cu species, which alters the surface chemistry of electrodes. Li + promotes the dissolution of Cu, leading to a metallic surface that favors CH 4 production, while K + and Cs + stabilize the Cu oxide and hydroxide species on the surface, resulting in higher faradaic efficiency for C 2 H 4 . A combination of ex situ and in situ techniques, including X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and electrochemical surface-enhanced Raman spectroscopy (EC-SERS), demonstrates cation-induced changes in the Cu oxidation state and surface structure directly affecting CO 2 RR product selectivity.