Design of an in-house ambient pressure AP-XPS using a bench-top X-ray source and the surface chemistry of ceria under reaction conditions.

A new in-house ambient pressure XPS (AP-XPS) was designed for the study of surfaces of materials under reaction conditions and during catalysis. Unique features of this in-house AP-XPS are the use of monochromated Al Kα and integration of a minimized reaction cell, and working conditions of up to 500 °C in gases of tens of Torr. Generation of oxygen vacancies on ceria and filling them with oxygen atoms were characterized in operando.