To really understand a complex challenge, it pays to take a close look at the details. NETL researchers are taking this approach as they use X-ray photoelectron spectroscopy (XPS) to understand and characterize rare earth oxides on the atomic level. The pioneering research was recently selected for publication in the June edition of the journal Surface Science Spectra. To view the study, go here.

Rare earth elements (REEs) are crucial in the development of technologies and tools vital to daily life, from cell phone batteries to medical imaging and water treatment applications. REEs are a set of 15 lanthanide elements within the periodic table that are actually not rare in nature, but occur in trace amounts as compounds with other metals. NETL is aggressively pursuing research and development for technologies capable of producing a domestic supply of high-purity, salable rare earth compounds.

Identifying and characterizing the elements to be extracted is the first step in determining the most efficient, cost-effective manner to extract the material. NETL researchers John Baltrus and Murphy Keller are using XPS to do just that, as detailed in the Surface Science Spectra journal article. The information will contribute toward REE identification methods and to increase the amount of pure REE product obtained for use in today’s technologies.

XPS is an analytical technique used to determine the surface composition of different materials by measuring the discreet energies of electrons emitted during X-ray irradiation. The chemical state of REEs can also be determined through this process, which is useful information in obtaining higher-purity REE products for eventual use in today’s critical technologies.

Baltrus explained the research is providing valuable knowledge to the scientific community that researchers can build upon as different techniques are developed for recovering REEs from coal and coal byproducts.

“Standard XPS spectra of certain REE-containing oxides are not yet readily available in the literature. Additionally, those that can be found are often low-quality or affected by surface contamination, which can lead to misidentification. Using XPS in characterizing REE oxides will help in correctly identifying and characterizing REEs as research into these valuable materials continues,” Baltrus said.

A domestic supply of REEs is critical in maintaining the nation’s energy security. Forward-thinking REE research at NETL contributes to the development of this important domestic energy solution while ensuring responsible stewardship of the environment.