X-ray Photoelectron Spectroscopy
X-ray photoelectron spectroscopy (XPS) is a widely used surface analysis technique providing information on the chemical nature and state of detected elements. It is a useful method to determine the surface composition of bio-organic systems and determine organic compositions on mineral surfaces. XPS is available to the research community at the Environmental Molecular Sciences Laboratory (EMSL) through open calls for proposals.
With the use of XPS, chemical information obtained can be further upgraded by expressing the XPS data in terms of concentrations of ingredients, classes of biochemical compounds, or various organic and inorganic compounds.
Imaging XPS system provides fast, quantitative, real-time imaging with high spatial resolution. It can quantitatively determine a sample’s elemental composition within the first 10nm of a surface and allows high-resolution scans to be taken of elemental peaks of interest, determining valuable chemical bonding information.
Research application
XPS can be used to study the biogeochemical and microbial processes that drive fate and transformations of nutrients in soil and shallow subsurface environment. This technique can contribute to understanding the mechanisms and biogeochemical conditions by which organic matter and microbial residues are stabilized or released by mineral surfaces and interfaces. This technique can also be used to study the surface composition of microorganisms to better understand a wide range of interactions involving the cells (aggregation, adhesion, biofilm formation, and infection) and the relationships between surface composition and surface structure.
- XPS supports the Terrestrial-Atmosphere Processes Integrated Research Platform by analyzing a wide range of chemical and spatial information—helping to uncover and further understand the drivers of various environmental fluxes, including atmospheric and soil interactions among others.
- XPS supports the Biogeochemical Transformations Integrated Research Platform by enabling new insights into molecular structure and activity, while also helping to answer fundamental questions about environmental chemical, physical, hydrologic, microbial, and atmospheric interactions. Additionally, EMSL offers a sample preparation workflow that allow researchers to rapidly analyze (in high throughput manner) the chemistry of soil organic matter associated with mineral surfaces.
Available instruments
- Temperature Programmed Desorption
- Ultraviolet Photoelectron Spectroscopy
- Icon Scattering Spectroscopy
- Fast entry load lock with pre-cooling device and full-size glove box
- Cluster/Ar+ ion gun
- Monchromated X-Ray Gun (Al and Ag anodes)
Tips for success
- Sample preparation, history, and providence must be discussed prior to sample submission and user analysis. Contact your science point of contact for sample-specific requirements.
Contributing team and resources
EMSL develops and deploys capabilities for the user program by conducting original research independently or in partnership with others and by adapting/advancing science and technologies developed outside of EMSL. In some instances, EMSL directly deploys mature capabilities developed by others where there is value for the EMSL user community. The following grants/activities, PI’s and teams contributed to the development of this capability:
- Qian Zhao and Mark Engelhard, DE-AC05-76RL01830, Environmental Molecular Sciences Laboratory
- Qian Zhao and Arunima Bhattacharjee, DE-AC05-76RL01830, Environmental Molecular Sciences Laboratory
Related publication
Cheng, C. H., Lehmann, J., & Engelhard, M. H. (2008). Natural oxidation of black carbon in soils: changes in molecular form and surface charge along a climosequence. Geochimica et Cosmochimica Acta, 72(6), 1598-1610. https://doi.org/10.1016/j.gca.2008.01.010