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SUMMARY:Electronic structure reading group - Arthur Hagopian
DTSTART:20261118T160000
DTEND:20261118T173000
DTSTAMP:20261106T142857Z
UID:423c180986d1d88f987451de1f76d1c972fcaee80c26904c55639dfc
CATEGORIES:Conferences - Seminars
DESCRIPTION:Arthur Hagopian\nArthur Hagopian from EPFL (CESA) will give a 
 talk.\n\nTitle: Polarization-Driven Water Activation at Electrocatalytic 
 Interfaces\nAbstract: \nWater activation constitutes a key elementary ste
 p in several electrochemical reactions\, including alkaline hydrogen evolu
 tion and acidic oxygen evolution. Yet\, while electrocatalytic activity is
  commonly discussed in terms of adsorbed intermediates\, considerably less
  is known about how an interfacial water molecule itself is brought into a
  sufficiently reactive electronic state before O–H bond cleavage and cha
 rge transfer. At electrified interfaces\, this process may be strongly inf
 luenced by the instantaneous structure\, electrostatic environment\, and c
 ollective organization of the surrounding solvent.\nIn previous work\, I p
 roposed a mechanism in which collective alignment of water dipoles can shi
 ft water electronic levels sufficiently to enable reduction or oxidation o
 f interfacial water\, leading respectively to radical-anion- or radical-ca
 tion-like states. This mechanism was demonstrated for an idealized\, order
 ed ferroelectric water layer. Here\, I investigate whether the same physic
 al picture survives in a realistic\, thermally fluctuating electrochemical
  interface.\nUsing ab initio molecular dynamics and electronic-structure d
 escriptors\, I study Pt(111)/water interfaces under different interfacial 
 charging conditions and in the presence of different electrolyte ions. I f
 ollow the energetic position of the water reduction and oxidation levels r
 elative to the metal Fermi level and relate their fluctuations to the loca
 l solvent environment\, including water orientation\, dipolar correlations
 \, and the interfacial local electrostatic potential.\nMore broadly\, this
  work points toward a different way of looking at electrochemical interfac
 es. Rather than describing the interface solely through average quantities
  such as mean water orientation\, average potential profiles\, or static i
 nterfacial structures\, I focus on the transient local configurations that
  continuously emerge from thermal fluctuations. Rare and short-lived solve
 nt arrangements may create highly specific electronic environments that ar
 e largely invisible in ensemble averages\, yet disproportionately importan
 t for reactivity. This perspective suggests that understanding electrochem
 ical interfaces may require identifying not only their average state\, but
  also the fleeting local states through which chemistry actually becomes p
 ossible.
LOCATION:MA B1 524 https://plan.epfl.ch/?room==MA%20B1%20524
STATUS:CONFIRMED
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