Nowadays, the design and synthesis of catalysts is a major challenge to address societal, environmental issues within the ecological transition. Hence, it is necessary to gain an understanding of the fundamental properties of catalysts at the atomic and electronic levels. Identification of the active catalyst phases under operando conditions is a significant drawback in heterogeneous catalysis. Until now, surface analysis of catalysts by XPS lab techniques is restricted to post-mortem/ante-mortem characterization of catalysts. Our consortium proposes developing a 2D membrane-cell for Lab-setup XPS systems inspired by environmental electron microscopy (high pressure-cells) and able to operate around ? 5 mbar of pressure, particularly suitable for optimized catalytic applications. The cell will contain a maximum volume of 0.5L with a transit time ? 30 sec, preventing thus mass transfer limitations (MTL). This consortium gathers physicists specialized in the elaboration and characterization of thin films/surface chemists, IMN and IRCELYON, as well as fluid mechanics, LMFA, designers, and engineers of vacuum devices, CRYOSCAN. The partners have complementary skills and means on a unique techno/scientific development such as a cell isolated from the vacuum by a graphene membrane containing: its sample holder, a photoelectron acceleration system and a powerful gas injection device. This new prototype membrane cell combined with laboratory photoelectron spectroscopy (XPS) will thus allow the development (IMN) and characterization of several types of catalysts under relevant catalytic reaction conditions without consequent modifications of the existing UHV-XPS system (IRCELYON).