Combining SECCM with Microspectroscopy for Evaluation of ROS Generation at non-Pt Fuel Cell Catalysts

Scanning electrochemical cell microscopy (SECCM) is the only technique which allows the study of a material using well-established bulk electrochemical techniques with a resolution of a few micrometer down to the nanometer regime. The measurement takes place in a nano- or microdroplet formed at the end of a nano- or micropipette in contact with the surface of interest. This allows e.g. study of single nanoparticle agglomerates or generally spatially resolved analysis of the sample. The analysis of the data is equivalent to the bulk experiment and often straightforward.

In this paper “Mapping Localized Peroxyl Radical Generation on a PEM Fuel Cell Catalyst Using Integrated Scanning Electrochemical Cell Microspectroscopy” by J. Edgecomb et al. SECCM using a HEKA ElProScan platform was combined with adsorption and fluorescence microscopy allowing the recording of spectra within a 10 µm wetted sample area. A fluorescent dye 6CFL was used to detect the generation of peroxyl radicals during the ORR at the non-Pt catalyst TaTiOx on a Nafion membrane which were indeed formed.

The measurements using this integrated SECCM setup were validated by RRDE bulk measurements and can further be applied to novel fuel cell catalysts.

Edgecomb J, Xie X, Shao Y, El-Khoury PZ, Johnson GE and Prabhakaran V (2020) Mapping Localized Peroxyl Radical Generation on a PEM Fuel Cell Catalyst Using Integrated Scanning Electrochemical Cell Microspectroscopy.
Front. Chem. 8:572563. doi: 10.3389/fchem.2020.572563

Scheme of the SECCM setup with integrated spectrometer for adsorption and fluorescence microspectroscopy in the droplet (left), fluorescence spectra within the droplet of a Nafion membrane with a layer of fluorescence dye 6CFL and active catalyst (middle) and fluorescence intensity during ORR at the active catalyst (right). Reproduced from J. Edgecomb et al. (2020) Front. Chem. 8:572563. Copyright by © 2020 Edgecomb, Xie, Shao, El-Khoury, Johnson and Prabhakaran.

Holiday reading

While spending some time outside the lab to recover and enjoy the holiday season, why not have some reading material at hand?

We collected some recent articles on scanning micropipette techniques which are gaining increasing popularity at the moment.

With scanning micropipette techniques, the local electrochemistry of your sample can be studied. A micropipette is filled with electrolyte to form a small droplet at the opening. This droplet is brought into contact with the sample and forms a miniaturized electrochemical cell. This way, common bulk electrochemical experiments can be performed on the micron scale with spatial resolution. Polpular applications are the study of corrosion, coatings, battery materials and (photo)catalysts.

These scanning techniques are commonly called either scanning electrochemical cell microscopy (SECCM) or scanning micropipette contact method (SMCM) and might employ either double-barrel or single barrel micropipettes. If the micropipette is not scanned in a regular pattern, but rather moved to specific spots to collect local data, the technique is also just called micropipette contact method.

Gateman, S.M., Halimi, I., Costa Nascimento, A.R. et al., Using macro and micro electrochemical methods to understand the corrosion behavior of stainless steel thermal spray coatings. npj Mater Degrad 2019, 3, 25. (

M. Dayeh, M. R. Z. Ghavidel, J. Mauzeroll, S. B. Schougaard, Micropipette Contact Method to Investigate High‐Energy Cathode Materials by using an Ionic Liquid, ChemElectroChem 2019, 6, 195. (

N. A. Payne, J. Mauzeroll, Identifying Nanoscale Pinhole Defects in Nitroaryl Layers with Scanning Electrochemical Cell Microscopy, ChemElectroChem 2019, 6, 5439. (

Beugré, R.; Dorval, A.; Lizotte Lavallée, L.; Jafari, M.; Byers, J.C., Local electrochemistry of nickel (oxy)hydroxide material gradients prepared using bipolar electrodeposition, Electrochimica Acta 2019, 319, 331-338. (

We wish you a successful end of the year and a good start into the next one!