Three-dimensional (3D) nanomaterials are being explored
extensively
to serve as efficient electrocatalyts, which can be designed through
the modification of electronic states of active sites in energy conversion
applications. In this work, for the first time, a series of hierarchical
polyhedral 3D nanostructures of Fe-doped manganese-based chalcogenides
MnX2 (X = S, Se, Te) incorporating amorphous carbon (C)
is synthesized using an Mn-based metal–organic framework as
the precursor via a two-step hydrothermal route. The MnX2/C hierarchical polyhedral nanostructures (HPNs) (X = S, Se, Te)
display remarkable results such as lower overpotentials of 305, 276,
and 246 mV at a current density of 10 mA cm–2 and
small Tafel slopes of 85, 90, and 48 mV dec–1, respectively.
Moreover, iron-doped MnX2 (Fe–MnX2/C-HPNs,
X = S, Se, Te) display improved electrocatalytic activity, achieving
lower overpotentials of 280, 246, and 210 mV at a current density
of 10 mA cm–2 and smaller Tafel slopes of 85, 65,
and 48 mV dec–1, respectively. The enhanced efficiency
of two-dimensional (2D)/3D hierarchical polyhedral nanostructures
(Fe–MnX2/C-HPNs, X = S, Se, Te) is due to the larger
specific surface area, easy charge transport, and integrated amorphous
carbon. Hence, the construction of exceptionally efficient and low-cost
electrocatalysts could be facilitated by this MOF-template approach
for multilayer nanostructured materials for future applications.
