Visualization of spatial electrochemical activity via a combined thermal-electric potentiostat

01 October 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The electrolysis of water, CO2 and N2 provide options for producing fossil-free fuels and feedstocks at global scales. Technological advancements are challenged by the complexity of phenomena spanning broad physical scales (angstroms to meters) and scientific domains. Further, activity is presently quantified indirectly, hindering disambiguation of catalytic and system effects. Here, we present a spatial thermal-electric potentiostat (STEP) which links local electrochemical activity to an associated operando heat signature. The STEP then directly maps catalytic activity with fine resolutions in temperature (10 mK), time (0.2 s) and space (0.1 mm), capturing operational phenomena as they occur. We demonstrate STEP’s potential for catalyst screening, degradation measurements and spatial mapping through water and CO2 electrolysis experiments up to 0.2 A cm-2. We identify rapid catalytic temperature spikes with activity (>10 K at 0.2 A cm-2) and localized activity fluctuations in operation, both which challenge many perceptions of the electrocatalyst and reaction environment during operation.


in situ

Supplementary materials

Supporting Info: Space-resolved mapping of catalytic activity in high current-density electrolysers by infrared imaging
Materials and methods, supplementary text, figures and graphs, and references for the supporting information. Includes the underlying reasoning for points made in the text, an extensive description of the setup and figures that support the main text.


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