2 research outputs found
Histidine-Derived Nontoxic Nitrogen-Doped Carbon Dots for Sensing and Bioimaging Applications
Nitrogen-doped (N-doped) photoluminescent
carbon dots (CDs) were
prepared by a one-pot microwave-assisted hydrothermal treatment using
histidine as the sole carbon source in the absence of acid, alkali,
or metal ions. With a diameter of 2–5 nm, the synthesized CDs
had apparent lattice fringes and exhibited an excitation-dependent
photoluminescent behavior. The CDs were highly yielded, well-dispersed
in aqueous solution, and showed high photostability in the solutions
of a wide range of pH and salinity. They were used as probes to identify
the presence of Fe<sup>3+</sup> ions with a detection limit of 10
nM. With confirmed nontoxicity, these CDs could enter the cancer cells,
indicating a practical potential for cellular imaging and labeling
Cobalt–Nickel Layered Double Hydroxides on Electrospun MXene for Superior Asymmetric Supercapacitor Electrodes
Flexible electrodes for energy storage and conversion
require a
micro-nanomorphology and stable structure. Herein, MXene fibers (MX-CNF)
are fabricated by electrospinning, and Co-MOF nanoarrays are prepared
on the fibers to form Co-MOF@MX-CNF. Hydrolysis and etching of Co-MOF@MX-CNF
in the Ni2+ solution produce cobalt–nickel layered
double hydroxide (CoNi-LDH). The CoNi-LDH nanoarrays on the MX-CNF
substrate have a large specific surface area and abundant electrochemical
active sites, thus ensuring effective exposure of the CoNi-LDH active
materials to the electrolyte and efficient pseudocapacitive energy
storage and fast reversible redox kinetics for enhanced charging–discharging
characteristics. The CoNi-LDH@MX-CNF electrode exhibits a discharge
capacity of 996 F g–1 at a current density of 1
A g–1 as well as 78.62% capacitance retention after
3,000 cycles at 10 A g–1. The asymmetric supercapacitor
(ASC) comprising the CoNi-LDH@MX-CNF positive electrode and negative
activated carbon electrode shows an energy density of 48.4 Wh kg–1 at a power density of 499 W kg–1 and a capacity retention of 78.9% after 3,000 cycles at a current
density of 10 A g–1. Density-functional theory calculations
reveal the charge density difference and partial density of states
of CoNi-LDH@MX-CNF confirming the large potential of the CoNi-LDH@MX-CNF
electrode in energy storage applications