The ALBA light source started its operation in 2012. One of the seven beamlines built in this first phase is the CIRCE beamline, with two endstations in different branches, dedicated to Photoemission Electron Microscopy (PEEM) and Near Ambient Pressure Photoemission spectroscopy (NAPP).

In this talk we will introduce the NAPP endstation. A differentially pumped electron energy analyzer, developed by Salmeron and Schlögl groups and now available commercially, allows extending the standard UHV XPS (X-ray Photoelectron Spectroscopy) technique to sample pressures up to 20 milibar [1]. The surface reactivity and structure in real environments can reveal dramatic differences with respect to the traditional solid-vacuum studies. The possibility to work with these instruments under realistic conditions and get information during the reactions or processes of interest has a great impact in heterogeneous catalysis, fuel cells, photovoltaics, batteries, corrosion, biological systems and many other fields.
The endstation capabilities will be described and illustrated with some examples of recent research studies [2].

[1] (a) D.F. Ogletree, H. Bluhm, G. Lebedev, C.S. Fadley, Z. Hussain, M. Salmeron, Review of Scientific Instruments 73 (2002) 3872 ; (b) H. Bluhm, J. Elec. Spec. Rel. Phenom., 177 (2010) 71; (c) D. F. Ogletree, H. Bluhm, E. D. Hebenstreit, M. Salmeron, Nucl. Instrum. Methods Phys. Res. Sect. A 601 (2009) 151 ; (d) M. Salmeron, R. Schlögl, Surf. Sci. Rep. 63 (2008) 169.

[2] N. J. Divins, I. Angurell, C. Escudero, V. Pérez-Dieste, J. Llorca, Science 346, issue 6209 (2014), 620