Understanding the Origin of Highly Selective CO2 Electroreduction to CO on Ni,N-doped Carbon Catalysts |
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| Authors: | David M Koshy Dr Shucheng Chen Dr Dong Un Lee Dr Michaela Burke Stevens Ahmed M Abdellah Samuel M Dull Gan Chen Dr Dennis Nordlund Dr Alessandro Gallo Dr Christopher Hahn Dr Drew C Higgins Dr Zhenan Bao Dr Thomas F Jaramillo |
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| Institution: | 1. SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA, 94305 USA;2. Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada;3. Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305 USA;4. Stanford Synchotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 USA;5. SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 USA |
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| Abstract: | Ni,N-doped carbon catalysts have shown promising catalytic performance for CO2 electroreduction (CO2R) to CO; this activity has often been attributed to the presence of nitrogen-coordinated, single Ni atom active sites. However, experimentally confirming Ni?N bonding and correlating CO2 reduction (CO2R) activity to these species has remained a fundamental challenge. We synthesized polyacrylonitrile-derived Ni,N-doped carbon electrocatalysts (Ni-PACN) with a range of pyrolysis temperatures and Ni loadings and correlated their electrochemical activity with extensive physiochemical characterization to rigorously address the origin of activity in these materials. We found that the CO2R to CO partial current density increased with increased Ni content before plateauing at 2 wt % which suggests a dispersed Ni active site. These dispersed active sites were investigated by hard and soft X-ray spectroscopy, which revealed that pyrrolic nitrogen ligands selectively bind Ni atoms in a distorted square-planar geometry that strongly resembles the active sites of molecular metal–porphyrin catalysts. |
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| Keywords: | CO2-Reduktion Elektrokatalyse Heterogene Katalyse Dotierter Kohlenstoff Röntgenabsorptionsspektroskopie |
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