In situ and non situ surface x-ray scattering studies of in plane Cs+ ordering in Helmholtz planes of Pt(111) surface

TL;DR

This study investigates the in-plane ordering of Cs+ ions on a Pt(111) surface using surface X-ray scattering, comparing in situ and non situ conditions with a novel transmission cell for high-temperature measurements.

Contribution

It introduces a new transmission cell enabling in situ and non situ surface X-ray scattering measurements during electrochemical experiments.

Findings

(2x2) in-plane scattering peaks are weak in situ and grow under non situ conditions.

Differences between in situ and non situ conditions are analyzed and modeled.

Surface emersion affects Cs+ ordering observed in scattering experiments.

Abstract

In-plane ordering of Cs+ layers in Helmhotlz planes was studied on Pt(111) surface in 0.1 M CsF electrolyte solutions with synchtrotron surface x-ray scattering techniques. The ordering was measured in a new transmission cell, designed for in situ and non situ measurements and high-temperature sample annealing all in the cell without sample transfer steps. At -850 mV vs. Ag/AgCl, (2x2) in-plane scattering peaks were weak under in situ condition and grew rapidly under non situ condition as the surface emersed from the electrolyte. The models for the (2x2) structures are presented and differences between in situ and non situ conditions are discussed.