Screening of CO2 electroreduction catalysts

The electroreduction of carbon dioxide is an important reaction in view of fuels for both fuel cells and redox flow batteries as well as towards a carbon neutral energy cycle. Hence the reaction has been intensively studied and a range of different catalyst materials have been presented.

In today’s paper “Scanning electrochemical microscopy screening of CO2 electroreduction activities and product selectivities of catalyst arrays” by Francis D. Mayer et al. Sn/SnOx catalysts are investigated using SECM. The final goal of this approach is to obtain a high-throughput screening procedure with the ability of spatial resolution to evaluate local activity changes in the catalysts.

Here, the authors show the capability of SECM for CO2 electroreduction catalyst screenings by comparing three different Sn/SnOx materials towards the production of H2, COad and HCOOand their selectivity. In contrast to traditional SECM experiments where the microelectrode is biased at a constant potenial while moving across the surface, the products are detected in a CV cycle as shown below. This allows for a simultaneous detection of all three relevant reaction products in one experiment.

Presentation of A CV at a Pt microelectrode for the simultaneous detection of H2, COad and HCOO-.
Fig. 1: Cyclic voltammograms indicating the different redox processes during CO2 electroreduction. Image taken from Mayer, F.D., et al. Commun Chem 3, 155 (2020). https://doi.org/10.1038/s42004-020-00399-6.

The screening of the Sn/SnOx catalyst array was performed by conducting and analysing a fast CV (1 V/s) at the Pt microelectrode at each measuring point of the 8750 x 1250 µm map. The Potmaster software of the ElProScan allows to perform matrix scans where advanced protocols can be executed and analyzed which made these experiments possible.

SECM maps created from the analysis of fast CV scans at each point of the map.
Fig. 2: Resulting maps of the catalyst array for each product as analyzed in the CV scans. Image taken from Mayer, F.D., et al. Commun Chem 3, 155 (2020). https://doi.org/10.1038/s42004-020-00399-6.

The analysis showed indeed differences in the product selectivities and shows the great potential of using the combined SECM-CV approach for larger catalyst arrays.

Read the full paper here: Mayer, F.D., Hosseini-Benhangi, P., Sánchez-Sánchez, C.M. et al. Scanning electrochemical microscopy screening of CO2 electroreduction activities and product selectivities of catalyst arrays. Commun Chem 3, 155 (2020). https://doi.org/10.1038/s42004-020-00399-6

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