2025-10-01 ミネソタ大学
Researchers in the Center for Programmable Energy Catalysis, headquartered at the University of Minnesota, have now shown that electron sharing in catalysis can be directly measured by a technique they invented called Isopotential Electron Titration (IET). Image credit: Center for Programmable Energy Catalysis
＜関連情報＞
- https://cse.umn.edu/college/news/energy-researchers-discover-part-electron-drives-catalysis
- https://pubs.acs.org/doi/10.1021/acscentsci.5c00851
等電位電子滴定：水素吸着質-金属電荷移動 Isopotential Electron Titration: Hydrogen Adsorbate-Metal Charge Transfer
Justin A. Hopkins,Benjamin J. Page,Shengguang Wang,Jesse R. Canavan,Jason A. Chalmers,Susannah L. Scott,Lars C. Grabow,James R. McKone,Paul J. Dauenhauer,and Omar A. Abdelrahman
ACS Central Science Published: September 15, 2025
DOI:https://doi.org/10.1021/acscentsci.5c00851
Abstract
The extent of charge transfer between an adsorbate and thermocatalytic surface plays a key role in determining catalytic activity, but direct and quantitative measures have remained elusive. Here, we report the method of isopotential electron titration (IET), an approach that directly measures charge transfer between adsorbates and catalytic surfaces. Charge transfer between Pt and adsorbed hydrogen adatoms was investigated using a catalytic condenser, where the Pt surface was separated from a p-type silicon layer by a hafnia dielectric film. By forcing the Pt and Si layers into isopotential conditions, charge transfer between the adsorbate and Pt surface was titrated through an external circuit. Hydrogen atoms donated electrons to Pt upon adsorption, which was quantitatively reversed upon desorption. Across a temperature range of 125–200 °C (surface hydrogen fractional coverages of 80–100%), the charge transferred to Pt by an adsorbed hydrogen atom was measured to be 0.19 ± 0.01% |e|/H. Bader charge analysis of the extent of charge transfer was in agreement with experimental measurements, with a calculated net donation of 0.4% |e|/H. The ability to experimentally quantify surface charge transfer provides an electronic-based approach to characterize catalytic surfaces, the adsorbed moieties residing on them, and the chemical reactions they accelerate.
