It has been known
that dedicated photoinduced catalysis over artificial
functional nanostructures and/or combined with effective peroxymonosulfate
(PMS) activations toward highly effective greener synthesis and/or
environmental remediation have been well recognized to be one of the
best options for efficiently exploiting solar light to convert into
chemical fuel and energy. Novel Zn
x
Cu1–x
Fe2O4 (0 ≤ x ≤ 1) hierarchical yolk–shell hollow nano-microspheres/PMS/Vis
(ZCF/PMS/Vis) tandem systems with remarkable light harvesting capability
and superior environmental catalytic activity toward elimination of
antibiotic enrofloxacin up to 90.5% removal efficiency have been successfully
designed and fabricated via combined solvothermal strategy and morphologically
conserved sintering in this current work. The physicochemical characteristics,
diverse structures including the spinel crystal structures, hierarchical
nano-microstructure, and internal correlations of structure-dependent
properties, and the catalytic reaction mechanism in terms of the synergetic
effect between instant PMS activation and dedicated photoinitiated
catalysis have been methodically inspected and thoroughly illustrated
by a variety of in/ex situ physicochemical ways, and the diverse microstructures
including solid microspheres with villiform surfaces, YSHMs composed
of exquisite particles, and YSHM alternative formation of diverse
microstructures could be ultimately tailored and formed. ZCF YSHMs
exhibit higher efficiency of both dedicated catalysis and spatial
charge separations owing to their physicochemical characteristics
and surface structures, namely, more surface oxygen vacancies, highest
specific surface area, and interior structures. Specifically, as confirmed
by primary combined characterizations, namely, room-temperature Mössbauer,
in situ spin-trap EPR, SPV, ns-TAS, and in situ Raman and sequential
investigations, the primary reactive oxygen species were deemed to
be SO4
·– and ·OH
radicals, which generated instantly and simultaneously through surface
covalent Cu2+ ions. Sequential-derived Cu(II)/Cu(III)/Cu(II)
redox cycling initiated PMS activations and photoinitiated catalysis,
and the superior catalytic performance as derived from ZCF HYSHM hierarchical-structured
spinels could be primarily attributed to the diverse bulk and surface
structures, highly efficient photonic energy harvesting, spatial charge
separations and surface–interfacial transfers, more surface
oxygen vacancies, and crucial reactive species including SO4
·– and ·OH generations with
long radical lifetimes up to 14.57 μs. The work could bring
a brand new and deep insight into further understanding of both the
intrinsic spinel structural influence factors governing the catalytic
properties and the synergetic effect between instant PMS activation
and simultaneous photoinitiated catalysis at the molecular level,
which would be very beneficial for mimicking the natural photosynthetic
solar energy harness system with marvelous featured properties in
both environmental e...