Electric-field-driven electrochemical CO2 reduction of sharpened Sn/Cu catalysts

• Published in: Applied surface science 2021-11, Vol.565, p.150460, Article 150460
• Main Authors: Dong, Wan Jae, Lim, Jin Wook, Park, Jae Yong, Yoo, Chul Jong, Baek, Sangwon, Cho, Won Seok, Kim, Wanho, Lee, Jong-Lam
• Format: Article
• Language: English
• Subjects: Bimetallic; Carbon dioxide reduction; Carbon monoxide; Geometric structure; Local electric field; Sn/Cu catalyst
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.150460

[Display omitted] •Sn/Cu cones, rods, and films were fabricated by template-based nanoimprint lithography.•Relationship between sharpness of Sn/Cu catalysts and CO2 reduction activity was investigated.•Sn/Cu cones exhibited much better faradaic efficiency of CO = 82.7% than foil (41.3%) and rods (59.7%).•Local electric field induced by the sharp tip increases the CO selectivity. Sharpening of noble metal catalysts has been proven to enhance the performance of CO2 electrochemical reduction to CO. However, this approach has not been validated for non-precious metal catalysts such as Cu-based bimetallic catalysts. Moreover, the morphology of sharpened catalysts was relatively random and non-uniform, making it difficult to quantify the curvature of nanostructures. Here, we experimentally studied the relationship between sharpness of Sn/Cu catalysts with their activity through the fabrication of Sn/Cu foil, rods, and cones. The Sn/Cu catalysts were fabricated by template-based nanoimprint lithography, electroplating of Cu film, and electroless coating of Sn nanoparticles. The finite-element-based simulation provides evidence that the local electric field intensified as the curvature of catalysts increased. As a result, Sn/Cu cones exhibited much better faradaic efficiency of CO (FECO) = 82.7% and current density of CO (jCO) = 5.43 mA/cm2 than Sn/Cu foil (FECO = 41.3% and jCO = 2.29 mA/cm2) and Sn/Cu rods (FECO = 59.7% and jCO = 3.87 mA/cm2). This work reveals that the local electric field induced by the sharp tip plays a significant role in improving the FECO and lowering the onset potential of CO2 reduction reaction.