Estimating surface electric fields using reactive formic acid probes and SEM image brightness analysis

Jake T. Gray, Kriti Agarwal, Jeong Hyun Cho, Jung Il Yang, Su Ha

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


By changing the electrical bias imposed on a Ni catalyst attached to an external circuit, the selectivity of catalytic formic acid decomposition is shown to change—favoring CO2/H2 production under negative bias and CO/H2O production under positive bias. A method for estimating the strength of externally generated surface electric fields by measuring this selectivity change is presented and used to approximate field strengths on the order of 0.20 V/nm. A COMSOL model of the catalyst was created which indicated that the presence of Ni particles increased field strength and uniformity across the catalyst. Comparing this model to SEM imaging of the catalyst verified that the field strengths are highest on the surface of the catalyst particles, pore edges, and microscopic defects. The methods developed herein may be useful to future reaction engineers seeking to incorporate applied electric fields into process designs.

Original languageEnglish (US)
Article number125640
JournalChemical Engineering Journal
StatePublished - Dec 15 2020

Bibliographical note

Funding Information:
This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1347973. Funding by the Research and Development Program of the Korea Institute of Energy Research ( KIER ) (No. C0-2420 ), Republic of Korea is also gratefully acknowledged. Special thanks to the Franceschi Microscopy and Imaging Center (FMIC) at WSU for the use of their electron microscope expertise and facilities. K.A. and J.H.C. acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing computational resources. This work was partially supported by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-1420013.


  • COMSOL model
  • Formic acid decomposition
  • SEM brightness imaging
  • Selectivity enhancement
  • Surface electric field

How much support was provided by MRSEC?

  • Partial


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