Environmental Science & Technology,
Journal Year:
2024,
Volume and Issue:
58(24), P. 10817 - 10827
Published: June 4, 2024
Direct
photoreduction
of
FeIII
is
a
widely
recognized
route
for
accelerating
FeIII/FeII
cycle
in
photo-Fenton
chemistry.
However,
most
the
wavelengths
covering
full
spectral
range
are
insufficient
to
supply
enough
photon
energy
direct
reduction
process.
Herein,
hitherto
neglected
mechanism
that
indirect
pathway
initiated
by
light
energy-dependent
reactivity
variation
and
reactive
excited
state
(ES)
was
explored.
Evolution
excited-state
species
(*FeIII)
resulting
from
metal-centered
charge
excitation
(MCCE)
experimentally
verified
using
pulsed
laser
femtosecond
transient
absorption
spectroscopy
with
UV–vis
detection
theoretically
quantum
chemical
calculation.
Intense
photoinduced
intravalence
transition
observed
at
λ
=
380
466
nm,
revealing
quartet
4MCCE
doublet
2MCCE
their
exponential
processes.
Light
*FeIII
kinetically
certified
fitting
apparent
rate
constant
radical-chain
sequence
reactions.
Covalency
found
compensate
separation
following
photoexcitation
metal
center
MCCE
Fenton
photosensitizer.
The
established
as
model,
demonstrating
hole
delocalization
ES
can
be
leveraged
reaction
or
other
photocatalytic
schemes
based
on
electron
transfer
