In-situ and Operando Studies with Soft X-Ray Transmission Spectromicroscopy

Scanning transmission X-ray microscopy studies of electrochemical activation and capacitive behavior of Mn3O4 supercapacitor electrodes

“…It is expected that the approach developed in this investigation can be used for the analysis of activation behavior and charge storage mechanisms of other pseudocapacitive materials, such as V 2 O 3 . 44 In addition, we are actively developing in situ ow electrochemical devices for STXM, 61,62 which will enable in situ and operando types of studies of supercapacitor electrode materials. This journal is © The Royal Society of Chemistry 2022…”

In-situ Studies of Copper-based CO2 Reduction Electrocatalysts by Scanning Transmission Soft X-ray Microscopy

“…[12][13][14] While every CO2R catalyst, electrode and reactor leads to different local chemical reactive environments, we aimed to probe the conditions upon which Cuoxide species may exist under the CO2R conditions employed in our in-situ setup. To accomplish this, in our early in-situ studies, [27] we prepared a working electrode where we did not limit the amount of Cu that was electro-deposited, leading to the formation of micrometer scale deposits extending off the surface of the working electrode that may more closely mimic the thicker catalyst layers used in CO2R flow cells or membrane electrode assemblies. A typical STXM image of this electrode is shown in Fig.…”

“…(Fig. 2, the details are discussed in Section 6.2) [27,28] This in-situ micro-fluidic device is a major improvement compared to our previously reported 3D-printed device, [23]. It is more reliable with respect to electrolyte handling and can provide an electrolyte layer thickness of ~1.6 µm with a continuous flow of 25 µL/h, which provides good ionic conductivity while being thin enough for STXM studies at the Cu 2p edge (Section S-5, Fig.…”

“…This has motivated the development and application of in-situ/operando spectroscopy, microscopy and spectro-microscopy techniques to provide real-time and same-position characterization of working catalysts under electrochemical reaction conditions. [17][18] In this work, we have used in-situ soft X-ray scanning transmission X-ray microscopy (STXM) [19][20][21][22][23][24][25][26][27][28] to characterize Cu electrocatalysts in a micro-chip electrochemical cell designed to achieve electrolyte flow under applied electrochemical potentials which closely resemble the conditions experienced by Cu particles in a laboratory-scale CO2R reactor. STXM is a synchrotron-based spectro-microscopic technique that can simultaneously provide microscopic imaging of catalyst morphologies alongside spatially resolved (sub-50 nm spatial resolution) [29,30] spectroscopic characterization through near edge X-ray absorption fine structure (NEXAFS) spectroscopy [29] to enable quantitative, chemically selective imaging.…”

“…By utilizing a microfluidic-based flow electrochemical micro-chip reactor, in-situ STXM was conducted to characterize the morphology and chemical structure(s) present in electrodeposited Cu particles as catalysts under electrochemical CO2 reduction conditions as a function of time and electrode potential. The micro-fluidic based electrochemical device enabled controllable electrolyte flow and could achieve an aqueous electrolyte thickness < 2 μm [27,28] to enable soft X-ray transmission-mode measurements. In-situ STXM measurements provided a detailed quantitative evaluation of the particle evolution as a function of local chemical environments and applied potential.…”