Unveiling the structural transformations of the PW11Co@ZIF-67 nanocomposite induced by thermal treatment
Metadata
Show full item recordEditorial
Royal Society of Chemistry
Date
2022-11-02Referencia bibliográfica
Dalton Trans., 2022, 51, 17844. DOI: [10.1039/d2dt02976f]
Sponsorship
Portuguese Foundation for Science and Technology POCI-01-0145-FEDER-016422; European Commission; Portuguese Foundation for Science and Technology; European Commission UIDB/50006/2020 UIDP/50006/2020 2021.00771.CEECIND/CP1662/CT0007 CEECIND/03877/2018 CEECIND/00793/2018Abstract
A guest@host POM@ZIF nanocomposite—PW11Co@ZIF-67—has been synthesized using an in situ strategy.
This new nanocomposite exhibits (i) individually ZIF-67-cage-confined POM units, (ii) structural
defects in the ZIF-67 host induced by the POM, and (iii) charge transfer from the ZIF-67 to the confined
POM. In addition, it has served as a template to produce a set of derived samples by applying thermal
treatment at various temperatures (200, 400, 500, 600, and 950 °C) under a N2 flow. We have used multiple
characterization techniques, ICP-OES, CHNS analysis, XPS, ATR-IR, PXRD, Raman spectroscopy, N2/
CO2 adsorption analysis, CV, and TEM/EDS, to fully assess the thermally-induced variation tendencies.
The first two derivatives—D200 and D400—show the same nanoarrangement as the PW11Co@ZIF-67 precursor,
although with incipient signs of both POM and ZIF-67 structural decompositions. The following
samples—D500, D600, and D950—exhibit a carbonaceous nature consisting of C-embedded compositionally
complex nanoparticles that involve Co and W present as diverse species, metallic/oxide/phosphate/
phosphide. D500 presents the best intrinsic electrochemistry, probably due to the high proportion
of pyridinic N moieties doping its C matrix combined with small-sized and highly dispersed Co-enriched
nanoparticles. This study focuses on the need for a thorough physicochemical characterization of this
class of highly nanostructured materials with a view to exploring their application in electrocatalysis.