2 research outputs found
Luminescent Silver Clusters with Covalent Functionalization of Graphene
Brightly luminescent, atomically precise subnanometer
clusters
of silver protected by glutathione were covalently functionalized
by solution phase thiolated graphene using ligand exchange. A hybrid
molecule was formed, which was obtained in a nearly pure form by phase
transfer from the aqueous to the organic phase. The resulting hybrid
exhibited properties of both of these nanoscale materials. UV–vis,
luminescence, XPS, EDAX, TEM, and Raman spectroscopy were used to
characterize the hybrid structure, which showed the spectroscopic
characteristics of both the constituents. The luminescence of the
cluster was retained in the hybrid, along with features characteristic
of graphene. Atomically precise clusters with covalently linked graphene
will be useful for new applications in the areas of drug delivery,
sensors, and catalysis
Phosphorus-Induced One-Step Synthesis of NiCo<sub>2</sub>S<sub>4</sub> Electrode Material for Efficient Hydrazine-Assisted Hydrogen Production
Rational
control of the reaction parameters is highly important
for synthesizing active electrocatalysts. NiCo2S4 is an excellent spinel-based electrocatalyst that is usually prepared
through a two-step synthesis. Herein, a one-step hydrothermal route
is reported to synthesize P-incorporated NiCo2S4. We discovered that the inclusion of P caused formation of the NiCo2S4 phase in a single step. Computational studies
were performed to comprehend the mechanism of phase formation and
to examine the energetics of lattice formation. Upon incorporation
of the optimum amount of P, the stability of the NiCo2S4 lattice was found to increase steadily. In addition, the
Bader charges on both the metal atoms Co and Ni in NiCo2S4 and P-incorporated NiCo2S4 were
compared. The results show that replacing S with the optimal amount
of P leads to a reduction in charge on both metal atoms, which can
contribute to a more stable lattice formation. Further, the electrochemical
performance of the as-synthesized materials was evaluated. Among the
as-synthesized nickel cobalt sulfides, P-incorporated NiCo2S4 exhibits excellent activity toward hydrazine oxidation
with an onset potential of 0.15 V vs RHE without the assistance of
electrochemically active substrates like Ni or Co foam. In addition
to the facile synthesis method, P-incorporated NiCo2S4 requires a very low cell voltage of 0.24 V to attain a current
density of 10 mA cm–2 for hydrazine-assisted hydrogen
production in a two-electrode cell. The free energy profile of the
stepwise HzOR has been investigated in detail. The computational results
suggested that HzOR on P-incorporated NiCo2S4 was more feasible than HzOR on NiCo2S4, and
these findings corroborate the experimental evidence