FeO@NiFeO Nanoparticles with Enhanced Electrocatalytic Properties for Oxygen Evolution in Carbonate Electrolyte.

The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting are crucial challenges in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of FeO@NiFeO core-shell nanoheterostructures and the characterization of their electrocatalytic performance toward the oxygen evolution reaction (OER). Such nanoparticles (NPs) were produced by a two-step synthesis procedure involving the colloidal synthesis of FeO nanocubes with a defective shell and the posterior diffusion of nickel cations within this defective shell.

Toward the Use of Two-Color Emission Control in Upconverting NaYF:Er, Yb Nanoparticles for Biomedical Imaging.

In the interest of generating new biomedical sensing techniques as well as improving those that currently exist, a great deal of attention has been given to upconverting lanthanide nanoparticles in recent years. In order to develop these nanoparticles for use in multiplexed and ratiometric sensing techniques, many recent studies have focused on experimental control of their emission wavelengths. Here we describe a new method for controlling the relative intensity of green and red emission bands in NaYF:Yb, Er nanoparticles via control of the excitation pulse repetition rate.

Control of Green and Red Upconversion in NaYF:Yb,Er Nanoparticles by Excitation Modulation.

Control of the two strongest upconversion emission lines in NaYF:Yb, Er nanoparticles is demonstrated by varying the excitation repetition rate. This technique may enable new multiplexed sensing modalities based on multicolor luminescent nanoparticles, currently contemplated for biomedical imaging and diagnostics.