Reaction mechanism and kinetics for CO<sub>2</sub> reduction on nickel single atom catalysts from quantum mechanics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32382033.
- Also identified by DOI 10.1038/s41467-020-16119-6 and PMC identifier 7205999.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Experiments have shown that graphene-supported Ni-single atom catalysts (Ni-SACs) provide a promising strategy for the electrochemical reduction of CO<sub>2</sub> to CO, but the nature of the Ni sites (Ni-N<sub>2</sub>C<sub>2</sub>, Ni-N<sub>3</sub>C<sub>1</sub>, Ni-N<sub>4</sub>) in Ni-SACs has not been determined experimentally. Here, we apply the recently developed grand canonical potential kinetics (GCP-K) formulation of quantum mechanics to predict the kinetics as a function of applied potential (U) to determine faradic efficiency, turn over frequency, and Tafel slope for CO and H<sub>2</sub> production for all three sites. We predict an onset potential (at 10 mA cm<sup>-2</sup>) U<sub>onset</sub> = -0.84 V (vs. RHE) for Ni-N<sub>2</sub>C<sub>2</sub> site and U<sub>onset</sub> = -0.92 V for Ni-N<sub>3</sub>C<sub>1</sub> site in agreement with experiments, and U<sub>onset</sub> = -1.03 V for Ni-N<sub>4</sub>. We predict that the highest current is for Ni-N<sub>4</sub>, leading to 700 mA cm<sup>-2</sup> at U = -1.12 V. To help determine the actual sites in the experiments, we predict the XPS binding energy shift and CO vibrational frequency for each site.