Sang-Won Lee

All Publications

• On-line Inductively Coupled Plasma Mass Spectrometry Reveals Material Degradation Dynamics of Au and Cu Catalysts during Electrochemical CO2 Reduction. Journal of the American Chemical Society Yan, K., Lee, S. W., Yap, K. M., Mule, A. S., Hannagan, R. T., Matthews, J. E., Kamat, G. A., Lee, D. U., Stevens, M. B., Nielander, A. C., Jaramillo, T. F. 2025

  Abstract

  A significant challenge in commercializing electrochemical CO2 reduction (CO2R) is achieving catalyst durability. In this study, online inductively coupled mass spectrometry (ICP-MS) was used to investigate catalyst degradation via nanoparticle detachment and/or dissolution into metal ions under CO2R operating conditions in 0.1 M KHCO3. We developed an experimental framework with ex situ characterization to validate the online ICP-MS method for in situ evaluation of degradation from metal foils. By varying the applied potential and microenvironment (CO2 vs N2-saturated electrolyte), we gained insights into the degradation of Au and Cu foils under CO2R and hydrogen evolution reaction (HER) conditions. While both Au and Cu foils were observed to be stable to dissolution in these regimes, degradation via nanoparticle detachment from the foil surface at the femtogram scale was observed as a function of reaction conditions, providing new insights into material degradation mechanisms. When applying potential steps at -0.1 and -1.0 V vs the reversible hydrogen electrode (RHE), Au was found to degrade via nanoparticle detachment under CO2R operating conditions more than under HER conditions, while Cu was found to degrade via nanoparticle detachment in similar amounts during both reactions. Au lost ∼1.8× more mass and ∼7.5× more nanoparticles than Cu under CO2R operating conditions. This study demonstrates the use of online ICP-MS to gain insight into the degradation of Au and Cu, the importance of studying unconventional degradation mechanisms such as nanoparticle detachment, and that online ICP-MS can be further utilized to gain fundamental understanding of catalyst durability for a variety of reaction systems.

  View details for DOI 10.1021/jacs.4c13233

  View details for PubMedID 39871661

• <i>Operando</i> Surface-Enhanced Infrared Spectroscopy Connects Interfacial Dynamics with Reaction Kinetics During Electrochemical CO₂ Reduction on Copper ACS CATALYSIS Matthews, J. E., Acosta, J., Lee, S., Oh, D., Lin, T. Y., Yap, K. K., Chen, J., Jang, J., Lee, D., Nielander, A. C., Jaramillo, T. F. 2024

  View details for DOI 10.1021/acscatal.4c05532

  View details for Web of Science ID 001380955800001

• Homogeneously Mixed Cu-Co Bimetallic Catalyst Derived from Hydroxy Double Salt for Industrial-Level High-Rate Nitrate-to-Ammonia Electrosynthesis. Journal of the American Chemical Society Jang, W., Oh, D., Lee, J., Kim, J., Matthews, J. E., Kim, H., Lee, S. W., Lee, S., Xu, Y., Yu, J. M., Hwang, S. W., Jaramillo, T. F., Jang, J. W., Cho, S. 2024

  Abstract

  Electrocatalytic nitrate reduction reaction (NO3RR) presents an innovative approach for sustainable NH3 production. However, selective NH3 production is hindered by the multiple intermediates involved in the NO3RR process and the competitive hydrogen evolution reaction. Hence, the development of highly efficient NO3RR catalysts is paramount. Herein, we report highly efficient bimetallic catalysts derived from hydroxy double salt (HDS). Under NO3RR conditions, Cu1Co1-HDS undergoes in situ reconstruction, forming nanocomposites of homogeneously distributed metallic Cu0 and Co(OH)2. Reconstruction-induced Cu0 rapidly converts NO3- to NO2-, which is further hydrogenated to NH3 by Co(OH)2. Homogeneously mixed Cu and Co species maximize this synergistic effect, achieving outstanding NO3RR performance including the highest NH3 yield rate (4.625 mmol h-1 cm-2) reported for powder-type NO3RR catalysts. Integration of Cu1Co1-HDS with a commercial Si solar cell attained 4.53% solar-to-ammonia efficiency from industrial wastewater-level concentrations of NO3- (2000 ppm), demonstrating practical application potential for solar-driven NH3 production. This study provides a strategy for enhancing the NH3 yield rate by optimizing the compositions and distributions of Cu and Co.

  View details for DOI 10.1021/jacs.4c07061

  View details for PubMedID 39177778

• CO₂ Conversion to Butene via a Tandem Photovoltaic-Electrochemical/Photothermocatalytic Process: A Co-design Approach to Coupled Microenvironments ACS ENERGY LETTERS Yap, K. K., Aitbekova, A., Salazar, M., Kistler, T. A., Pabon, M., Su, M. P., Watkins, N. B., Lee, S., Agbo, P., Weber, A. Z., Peters, J. C., Agapie, T., Nielander, A. C., Atwater, H. A., Jaramillo, T. F., Bell, A. T. 2024

  View details for DOI 10.1021/acsenergylett.4c01866

  View details for Web of Science ID 001292243900001

• Sub-volt conversion of activated biochar and water for H2 2 production near equilibrium via biochar-assisted water electrolysis CELL REPORTS PHYSICAL SCIENCE Kani, N. C., Chauhan, R., Olusegun, S. A., Sharan, I., Katiyar, A., House, D. W., Lee, S., Jairamsingh, A., Bhawnani, R. R., Choi, D., Nielander, A. C., Jaramillo, T. F., Lee, H., Oroskar, A., Srivastava, V. C., Sinha, S., Gauthier, J. A., Singh, M. R. 2024; 5 (6)

  View details for DOI 10.1016/j.xcrp.2024.102013

  View details for Web of Science ID 001293785400001

• Titanium Silicide: A Promising Candidate of Recombination Layer for Perovskite/Tunnel Oxide Passivated Contact Silicon Two-Terminal Tandem Solar Cells. ACS applied materials & interfaces Pyun, D., Choi, D., Bae, S., Lee, S. W., Song, H., Jeong, S. H., Lee, S., Hwang, J. K., Cho, S., Lee, H., Woo, M., Lee, Y., Kim, K., Kim, Y., Lee, C., Choe, Y., Kang, Y., Kim, D., Lee, H. S. 2024

  Abstract

  This study proposes a titanium silicide (TiSi2) recombination layer for perovskite/tunnel oxide passivated contact (TOPCon) 2-T tandem solar cells as an alternative to conventional transparent conductive oxide (TCO)-based recombination layers. TiSi2 was formed while TiO2 was made by oxidizing a Ti film deposited on the p+-Si layer. The reaction formation mechanism was proposed based on the diffusion theory supported by experimental results. The optical and electrical properties of the TiSi2 layer were optimized by controlling the initial Ti thicknesses (5-100 nm). With the initial Ti of 50 nm, the lowest reflectance and highly ohmic contact between the TiO2 and p+-Si layers with a contact resistivity of 161.48 mΩ·cm2 were obtained. In contrast, the TCO interlayer shows Schottky behavior with much higher contact resistivities. As the recombination layer of TiSi2 and the electron transport layer of TiO2 are formed simultaneously, the process steps become simpler. Finally, the MAPbI3/TOPCon tandem device yielded an efficiency of 16.23%, marking the first reported efficiency for a device including a silicide-based interlayer.

  View details for DOI 10.1021/acsami.4c01864

  View details for PubMedID 38771721

• Maximizing efficiency: Numerical modeling and optimization of 2-terminal perovskite/silicon tandem devices with different bottom cell structures SOLAR ENERGY Song, H., Lee, S., Kang, Y., Kim, D., Lee, H. 2024; 273

  View details for DOI 10.1016/j.solener.2024.112548

  View details for Web of Science ID 001233523200001

• Bias-free solar NH₃ production by perovskite-based photocathode coupled to valorization of glycerol NATURE CATALYSIS Tayyebi, A., Mehrotra, R., Al Mubarok, M., Kim, J., Zafari, M., Tayebi, M., Oh, D., Lee, S., Matthews, J. E., Lee, S., Shin, T., Lee, G., Jaramillo, T. F., Jang, S., Jang, J. 2024

  View details for DOI 10.1038/s41929-024-01133-4

  View details for Web of Science ID 001194940900003

• Modeling diurnal and annual ethylene generation from solar-driven electrochemical CO₂ reduction devices ENERGY & ENVIRONMENTAL SCIENCE Yap, K. K., Wei, W. J., Pabon, M., King, A. J., Bui, J. C., Wei, L., Lee, S., Weber, A. Z., Bell, A. T., Nielander, A. C., Jaramillo, T. F. 2024

  View details for DOI 10.1039/d4ee00545g

  View details for Web of Science ID 001176280900001

• Controlling Mass Transport in Direct Carbon Dioxide Zero-Gap Electrolyzers via Cell Compression ACS SUSTAINABLE CHEMISTRY & ENGINEERING Lee, D., Joensen, B., Jenny, J., Ehlinger, V. M., Lee, S., Abiose, K., Xu, Y., Sarkar, A., Lin, T. Y., Hahn, C., Jaramillo, T. F. 2023; 11 (46): 16661-16668

  View details for DOI 10.1021/acssuschemeng.3c05494

  View details for Web of Science ID 001108321300001

• Potassium chloride passivation for sputtered SnO2 to eliminate hysteresis and enhance the efficiency of perovskite solar cells JOURNAL OF ALLOYS AND COMPOUNDS Jeong, S., Hwang, J., Hwang, J., Lee, S., Lee, W., Lee, S., Pyun, D., Cho, S., Choe, Y., Lee, H., Kim, D., Kang, Y. 2023; 968

  View details for DOI 10.1016/j.jallcom.2023.171890

  View details for Web of Science ID 001079120400001

• A framework for understanding efficient diurnal CO2 reduction using Si and GaAs photocathodes CHEM CATALYSIS Yap, K. K., Lee, S., Steiner, M. A., Acosta, J., Kang, D., Kim, D., Warren, E. L., Nielander, A. C., Jaramillo, T. F. 2023; 3 (6)

  View details for DOI 10.1016/j.checat.2023.100641

  View details for Web of Science ID 001023692400001

• Sputtered PbI2 with Post-Processing for Perovskite Solar Cells SOLAR RRL Hwang, J., Lee, S., Lee, W., Bae, S., Kang, D., Jeong, S., Lee, S., Pyun, D., Hwang, J., Cho, S., Kim, D., Kang, Y., Lee, H. 2023

  View details for DOI 10.1002/solr.202300214

  View details for Web of Science ID 000993495500001

• First Demonstration of Top Contact-Free Perovskite/Silicon Two-Terminal Tandem Solar Cells for Overcoming the Current Density Hurdle ACS APPLIED ENERGY MATERIALS Pyun, D., Lee, S., Kim, Y., Jang, G., Choi, D., Jeong, S., Song, H., Lee, S., Cho, S., Kim, J., Kang, D., Lee, H., Hyun, J., Lee, C., Park, H., Hwang, J., Lee, W., Jeon, N., Seo, J., Kang, Y., Kim, D., Lee, H. 2023

  View details for DOI 10.1021/acsaem.2c02649

  View details for Web of Science ID 000935746600001