1Bilkent University, Chemistry Department, Ankara, Turkey
X-Ray based Operando Investigations have traditionally been carried out in Synchrotron facilities, due to demanding instrumentation and expertise.1, 2 However, although sporadic, several important lab-based XPS studies have also been reported.3 Emergence of Ionic Liquids with several promising properties, including their low volatility, has rekindled the use of XPS, especially for Operando types of measurements.4 Our initial investigations had also concentrated on ionic-liquids and their interfaces under dc and ac electrical bias, and extended to monitoring electrochemical reactions.5, 6 Recently, we have been investigating other low-volatile liquids and their drops on various substrates to tap into the Electrowetting phenomena.7-9 The common theme in all of our studies is the use of bias dependent shifts in the positions of the core-levels as reflection of the electrical potentials, recorded in a totally non-invasive and chemically resolved fashion. We use the magnitude and the frequency dependence of such potentials to extract pertinent information related to static, as well as dynamic chemical and/or electrochemical properties of the materials and their interfaces.10-13 Examples using ionic liquids, liquid poly-ethylene-glycol (PEG), their mixtures and containing other inorganic salts will be presented and discussed.
 Bluhm, H.; Andersson, K.; Araki, T.; Benzerara, K.; Brown, G. E.; Dynes, J. J.; Ghosal, S.; Gilles, M. K.; Hansen, H.-C.; Hemminger, J., J. Electron Spectrosc. Relat. Phenom. 150, 86 (2006).
 Foelske-Schmitz; A., Ruch; P.W., Kötz; R., J. Electron Spectrosc. Relat. Phenom. 182, 57 (2010).
 Lovelock, K. R. J., Villar-Garcia, I. J., Maier, F., Steinrück, H.-P. & Licence, P.. Chemical Reviews 110, 5158, (2010).
 Camci, M.; Aydogan, P.; Ulgut, B.; Kocabas, C.; Suzer, S., Phys. Chem. Chem. Phys. 8, 28434 (2016).
 Camci, M. T.; Ulgut, B.; Kocabas, C.; Suzer, S., ACS Omega 2, 478 (2017).
 Gokturk P.A.; Ulgut; B.; Suzer; S., Langmuir 34, 7301 (2018).
 Gokturk, P.A.; Ulgut; B.; Suzer; S., Langmuir 35, 3319 (2019).
 Uzundal, C.B., Ozgur, S.; Aydogan-Gokturk, P.; Wu, H.; Mugele, F.; Ulgut, B.; Suzer, S., Langmuir 35, 16989 (2019).
 Uzundal, C.B.; Aydogan-Gokturk, P.; Suzer, S.; Ulgut, B., J. Phys. Chem. C 123, 13192 (2019).
 P. Aydigan-Gokturk, S. Suzer (2021), J.Phys.Chem. C 25, 9453.
 S. Suzer, E. Strelcov, A. Kolmakov (2021), Analytical Chemistry 93, 13268-13272.
 M. Basaran, E. Oz, S. Ergoktas, C. Kocabas, B. Ulgut, A. Kocabas, S. Süzer (2022), Faraday Discussions 236, 86.