Premium
Understanding the Origin of Highly Selective CO 2 Electroreduction to CO on Ni,N‐doped Carbon Catalysts
Author(s) -
Koshy David M.,
Chen Shucheng,
Lee Dong Un,
Stevens Michaela Burke,
Abdellah Ahmed M.,
Dull Samuel M.,
Chen Gan,
Nordlund Dennis,
Gallo Alessandro,
Hahn Christopher,
Higgins Drew C.,
Bao Zhenan,
Jaramillo Thomas F.
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201912857
Subject(s) - catalysis , carbon fibers , electrochemistry , inorganic chemistry , pyrolysis , nitrogen , porphyrin , metal , polyacrylonitrile , materials science , active site , chemistry , photochemistry , organic chemistry , electrode , composite number , composite material , polymer
Ni,N‐doped carbon catalysts have shown promising catalytic performance for CO 2 electroreduction (CO 2 R) 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 CO 2 reduction (CO 2 R) 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 CO 2 R 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.