Atomic‐Scale Mapping of Impurities in Partially Reduced Hollow TiO₂ Nanowires

Abstract

The incorporation of impurities during the chemical synthesis of nanomaterials is usually uncontrolled and rarely reported because of the formidable challenge in measuring trace amounts of often light elements with sub‐nanometer spatial resolution. And yet, these foreign elements (introduced by doping, for example) influence functional properties. We demonstrate how the hydrothermal growth and a partial reduction reaction on hollow TiO2 nanowires leads to the introduction of parts per millions of boron, sodium, and nitrogen. This doping explains the presence of oxygen vacancies and reduced Ti states at the surface, which enhance the functional properties of TiO2. Our results were obtained on model metal oxide nanomaterials and they shed light on a general process that leads to the uncontrolled incorporation of trace impurities in TiO2, thereby, having a strong effect on applications in energy‐harvesting.

Enabling near-atomic–scale analysis of frozen water

“…This could unlock a more widespread application of APT to study individual molecules—a pioneer of the technique once referred to this as a “chimera” ( 16 ), i.e., an unachievable dream. There are sporadic reports of using APT for investigating molecular and biological materials ( 17 – 23 ) and for the characterization of nanoscale objects, i.e., nanoparticles ( 24 , 25 ), nanowires ( 26 , 27 ), or nanosheets ( 28 ). However, these samples are always taken out of their native or in operando environments and dedicated strategies had to be developed to enable specimen preparation ( 29 – 31 ).…”

Coupling Long‐Range Raman with X‐Ray Photoelectron Spectroscopy for Complementary Bulk and Surface Characterization of Battery Materials

“…Established strategies to transform the size of a material and improve the homogenization are ball‐milling, ultrasonication, and focused ion beam (FIB)‐induced transformation. Please note that all these techniques require pure conditions and bear a jeopardy of cross contamination (FIB: foreign ions, for example, Cr; ball milling: Fe compounds; ultrasonication: incorporation of Ti) [27–29] . An influence of the spot size on sample properties was not observed in conventional short‐range Raman measurements, which were performed as a control (see Figure 2).…”

Controlling the Oxidation of Magnetic and Electrically Conductive Solid-Solution Iron-Rhodium Nanoparticles Synthesized by Laser Ablation in Liquids

“…To remove the acetone, the suspension was left to dry in a nitrogen glovebox. The collected nanoparticles were co-electrodeposited with Ni according to the protocol detailed in ref [47]. The dried FeRh NP powder was dispersed in a Ni ion electrolyte followed by pouring the solution into a vertical electro-cell where a counter electrode (Pt mesh) positioned on top and a working electrode (Cu foil) placed at the bottom.…”