Rubbing Powders: Direct Spectroscopic Observation of Triboinduced Oxygen Radical Formation in MgO Nanocube Ensembles.

ABSTRACT: Powder compaction-induced surface chemistry in metal oxide nanocrystal ensembles is important for very diverse fields such as triboelectrics, tribocatalysts, surface abrasion, and cold sintering of ceramics. Using a range of spectroscopic techniques, we show that MgO nanocube powder compaction with uniaxial pressures that can be achieved by gentle manual rubbing or pressing (p ≥ 5 MPa) excites energetic electron-hole pairs and generates oxygen radicals at interfacial defect structures. While the identification of paramagnetic O^- radicals and their adsorption complexes with O₂ point to the emergence of hole centers, triboemitted electrons become scavenged by molecular oxygen to convert into adsorbed superoxide anions O₂ ^- as measured by ele

SUBMITTER: Schwab T 

PROVIDER: S-EPMC8521521 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature