High-resolution imaging of catalytic activity of a single graphene sheet using electrochemiluminescence microscopy

Here, the electrocatalytic activity of a single graphene sheet is mapped using electrochemiluminescence (ECL) microscopy with a nanometer resolution. The achievement of this high-spatial imaging relies on the varied adsorption of hydrogen peroxide at different sites on the graphene surface, leading to unsynchronized ECL emission. By shortening the exposure time to 0.2 ms, scattered ECL spots are observed in the ECL image that are not overlaid with the spots in the consecutive images. Accordingly, after stacking all the images into a graph, the ECL intensity of each pixel could be used to reflect the electrocatalytic features of the graphene surface with a resolution of 400 nm. This novel ECL method efficiently avoids the long-standing problem of classic ECL microscopy regarding the overlap of ECL emissions from adjacent regions and enables the nanometer spatial resolution of ECL microscopy for the first time.