Surface Analysis using X-Ray Photoelectron Spectroscopy:
HT-NAP-XPS

The innovative high-temperature ambient pressure X-ray photoelectron spectrometer (HT-NAP-XPS) EnviroESCA® from SPECS® extends conventional X-ray photoelectron spectroscopy (XPS) by enabling measurements at a pressure of up to 25 mbar and at a temperature of up to 1000 °C. This enables in situ analyses of reaction mechanisms and their intermediate stages. 

Typical fields of application of HT-NAP-XPS for surface analysis include:

• assemblies and materials for hydrogen applications, such as fuel cells, electrolyzers, and catalyst systems,
• degradation investigations of battery materials,
• high-efficiency photovoltaic materials,
• materials for heterogeneous catalysis,
• polymers, carbons, and carbon-based support materials,
• sorbents for DAC applications.

Operation:

When a sample is irradiated with monochromatic X-rays, electrons are released from the elements on the surface (photoelectric effect). These electrons are separated according to their kinetic energy using a hemispherical analyzer and measured on an electron detector. Their binding energy can be calculated from the difference between the energy of the X-rays and the measured kinetic energy of the electrons. The resulting photoelectron spectrum contains information on the elements present in the surface, their ratio to each other, and their respective oxidation states.

Advantages:

With conventional XPS, it is necessary to measure the samples in a high vacuum, which limits the measurable samples to solids. Sensitive materials that contain moisture, for example, cannot be measured with conventional XPS, but can be examined gently in a gas atmosphere under near-ambient conditions. Charge compensation for electrically insulated surfaces takes place through interaction with the gas phase. NAP-XPS also enables investigations on gases as well as liquids with low vapor pressure.

Equipment:

• multiple sample holder for simultaneous loading of up to 9 samples
• inert sample transfer under inert gas from glovebox to measuring position
• Al Kα monochromatic X-ray source, excitation energy of 1,486.6 eV
• heated sample platform up to 1,000 °C
• availability of the following gases for NAP experiments: N₂, Ar, He, H₂, O₂, H₂O, CO, CO₂, NH₃ (or gas mixtures)
• Ionoptika GCIB 10S for ion bombardment of the surface (cleaning, depth profiling)
• special holder for angle-resolved investigations

We offer:

• measurement of XPS overview spectra and high-resolution spectra
• Evaluation of measurement data using CasaXPS and interpretation of the results
• XPS investigations in a high vacuum and under a defined gas atmosphere on robust and sensitive materials
• in-situ surface modifications using reactive gases at a partial pressure of up to 900 mbar
• operando NAP-XPS studies at a partial pressure of up to 25 mbar
• depth profiling by controlled sputtering using argon ions/clusters

Research and development services for:

• chemical industry, e.g. research departments of catalyst manufacturers, battery manufacturers, solar module manufacturers
• metalworking industry, e.g. electroplating and other coating technologies
• medical technology, e.g. stent manufacturers, prosthesis manufacturers, pacemaker manufacturers
• energy technology companies