CMSP Seminar (Atomistic Simulation Webinar Series): Wednesday, 16 December 2020 at 11 a.m.

[Ivanissevich Nicoletta]

Virtual - Zoom Meeting

CMSP Atomistic Simulation Webinar Series
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* * * Wednesday, 16 December 2020 at 11:00 a.m.* * *

Speaker: *R. Kramer Campen* (Faculty of Physics, University of 
Duisburg-Essen)

Title: *Towards an Experimental, Femtosecond-resolved, view of Hydrogen 
Evolution on Platinum *
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Register in advance at: 
https://zoom.us/meeting/register/tJAkce2sqDwsE9HDzZUHA-pN05dkHNJ1_Jyv
After registering, you will receive a confirmation email containing 
information about joining the seminar.


Abstract:

Perhaps the most promising candidate for a source of H2 in future 
hydrogen driven global energy economy is the electrolytic splitting of 
H2O. For the reductive half of this reaction, i.e. the hydrogen 
evolution reaction (HER), Pt is the current champion catalyst and its 
cost and scarcity limit widespread deployment of devices based on this 
chemistry. The HER on Pt has been studied for decades and, for much of 
that time, an enormous amount of effort has been expended looking for 
alternative catalysts with similar activity and stability, largely 
without success. Part of the challenge of such materials discovery 
efforts is that why Pt is such an excellent HER catalyst is not well 
understood: there is no proposed HER mechanism that is consistent with 
all experimental observations (e.g. that can explain the dependence on 
electrolyte, Pt surface structure and pH).

Experimentally characterising HER mechanism is challenging: measurements 
under steady-state nonequilibrium conditions cannot generally 
distinguish intermediates from unwanted side products and elementary 
processes with timescales of femtoseconds to seconds are all important 
in understanding reactivity. We approach this problem by performing 
perturbation experiments in which we alter the chemical potential of Pt 
electrons using a femtosecond optical pulse and monitor interfacial 
structure using a combination of femtosecond resolved electrical and 
optical techniques as the electronic excitation dissipates.

In this talk I will show how experiments detecting femtosecond induced 
photocurrents suggest that charge transfer along the Pt-H bond can be 
inhibited by interfacial water structure, how the results of 
interface-specific vibrational spectroscopy suggest that adsorbed 
hydrogen readily diffuses between different types of atop adsorption 
sites, and how this mobility appears to dramatically change at 0 V vs. RHE.



CMSP, Condensed Matter & Statistical Physics Section
http://www.ictp.it/research/cmsp.aspx

The Abdus Salam International Centre for Theoretical Physics
https://www.ictp.it/  <https://www.ictp.it/>

    
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