  Recent developments in environmental and liquid cells equipped with electron
transparent graphene windows have enabled traditional surface science
spectromicroscopy tools, such as X-ray photoelectron spectroscopy (XPS),
photoemission electron microscopy (PEEM), and scanning electron microscopy
(SEM) to be applied to study solid-liquid and liquid-gas interfaces. Here, we
focus on the experimental implementation of PEEM to probe electrified
graphene-liquid interfaces using electrolyte-filled microchannel arrays as a
new sample platform. We demonstrate the important methodological advantage of
these multi-sample arrays: they enable the combination of the wide field of
view hyperspectral imaging capabilities from PEEM with the use of powerful data
mining algorithms to reveal spectroscopic and temporal behaviors at the level
of the individual microsample or the entire array ensemble
