Converting CO2 emissions into useful chemicals and fuels is an appealing strategy for mitigating the carbon footprint of industrial processes. The electrochemical CO2 reduction reaction (CO2RR) is a leading approach because it can couple with excess renewable energy to produce carbon neutral products. Down-stream chemical separation steps will introduce cost-barriers and hinder large-scale technological deployment; therefore, it is crucial to understand and control structure-property relationships that direct product selectivity. This talk describes our joint experimental and computational efforts for designing high performance CO2RR catalysts with desirable product selectivity. We use emerging synthetic approaches to produce monodispersed nanocatalyst systems with controlled size, surface structure, and atomic composition, and characterize the material's electronic structure and atomic coordination environment with synchrotron-based X-ray absorption spectroscopy and extended x-ray absorption fine structure analysis. This information is used to construct realistic catalyst models within density functional theory (DFT) to accurately identify structure-property relationships that direct system performance. We demonstrate this approach with a bimetallic gold-copper nanocatalysts system capped with organo-thiol ligands. Composition-dependent performance was correlated with DFT-based computational electrochemistry modeling to provide atomic-level reaction details about the catalyst structure, reactant binding energetics, and product selectivity during the electrochemical reaction. Our results describe how the unique surface structure of organo-thiol capped Au/Cu nanocatalysts enhanced product selectivity compared with other catalysts by stabilizing key CO2RR intermediates and preventing competitive H2 evolution reaction. These design considerations demonstrate that rational control over the nanocatalyst surface structure, i.e. “atomic engineering”, can be used to direct catalyst performance and produce extremely selectivity and active CO2RR systems.

Atomically engineered gold-copper nanocatalysts for selective CO2 conversion

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.