Professor Jing Guo, College of Chemistry, Beiging Normal University, China

Probing the surface chemistry of water and carbon dioxide with qPlus-AFM

This talk will introduce the development of qPlus-based atomic force microscopy, which allows to identify the positions of proton in water in real space by measuring the high-order electrostatic force between the CO terminated tip and the polar water molecule [1].

Then this talk will showcase the applications of H-sensitive AFM in the studies of surface water and carbon dioxide. 1) Bilayer hexagonal ice is regarded as the first intrinsic 2D ice crystal, which is robust against surface symmetry and corrugation [2]. Doping hydrogen atoms in such bilayer ice would result in the formation of hydronium-water monolayer on metal surfaces. The atomic structures of Eigen- and Zundel- type hydrated protons are directly visualized by qPlus-AFM. Moreover, tip manipulation enables the Eigen-Zundel interconversion, which is accompanied with a simultaneous proton transfer between the surface and water layer [3]. 2) We observed the aggregation of alkali metal cations on copper to stabilize the activated bending CO₂ molecule through cation coupled electron transfer and identified the atomic structure of 2D alkali carbonate films formed on Cu(111). These findings directly visualized the promoting role of alkali cations on the activation of carbon dioxide on copper and revealed the electron transfer mechanism.

[1] Nature. Communications. 9, 112 (2018)
[2] Phys. Rev. Lett. 129, 046001 (2022)
[3] Science 377, 315-319 (2022)