Because the penetrating depth of the fluorescence yield is known about ~ 1 μm in the soft X-ray region, the problems are ultra high vacuum (UHV) limitation and high pressure/aqueous environment insides the cell. In order to solve the vacuum requirement, the high vacuum expoy sealants (Varian inc.) for sealing the Si3N4 membrane provides the inside gas pressure up to 2 bar and dynamic liquid flowing as the pressure of main chamber is down to 10-9 torr. With the help of 100 nm thickness of Si3N4 membrane, an in-situ study, therefore, delivers the chemical and structural investigation under the environmental control of XAS and RIXS in the synchrotron center. The gas and liquid cell are the well-suited dynamic study for electrochemical and photocatalytic modification. The concepts of liquid/gas cell studied by XAS, XES, and RIXS technology are exclusively designed for the studies of in-situ electrochemical and photocatalytic reactions with controllable reactant species and amounts.
In the case of in-situ electrochemical modification, the role of graphene in the aqueous utilization is developed for the advanced battery, catalysis, and sensing applications. In the letter, a single-layer graphene is grown on Cu foil by chemical vapor deposition (CVD) method, and transferred on the Si3N4 window by the wet etching method. In contact with NaCl solution, the graphene network is characterized by a change of π* and σ* state relative to the structural distortion of sp2 configuration under soft X-ray experiment. As scanning the current-potential curve (cyclic voltamograms (CV)), a new defect formed in the initial formation is stable between potential ± 1.0 V, but shows the activated chemical reaction of C-OH and COOH bond as higher than the potential of ＋ 2.5 V. We provide a new spectroscopic approach for studying electrochemical reaction at electrode/electrolyte (solid/liquid) interface via the acid-like reactant. It is published in Journal of The Electrochemical Society, 160(9), C445-449, 2013.