Preparation and characterization of planar Ni–Au bimetallic model catalysts

•Au-rich surface alloy was formed by annealing Ni–Au thin films.•Electronic structure of the Ni–Au surface alloy was discussed by XPS.•Quantitative analysis in LEISS of the topmost Ni–Au layer was investigated.•CO adsorption indicated that Ni atoms were isolated by Au atoms on Ni–Au alloyed surface by PM-IRAS.