Tuning catalytic performance of platinum single atoms by choosing the shape of cerium dioxide supports.

The local coordination environment of single atom catalysts (SACs) often determines their catalytic performance. To understand these metal-support interactions, we prepared Pt SACs on cerium dioxide (CeO) cubes, octahedra and rods, with well-structured exposed crystal facets. The CeO crystals were characterized by SEM, TEM, pXRD, and N sorption, confirming the shape-selective synthesis, identical bulk structure, and variations in specific surface area, respectively.

Femtosecond Laser-Induced Emission of Coherent Terahertz Pulses from Ruthenium Thin Films.

We demonstrate emission of electromagnetic pulses with frequencies in the terahertz (THz) range from ruthenium thin films through a second-order nonlinear optical process. Ruthenium deposited on different substrates showed different THz emission properties. We provide evidence that for Ru on glass above a certain power threshold, laser-induced oxidation occurs, resulting in an increased slope of the linear dependence of the THz electric field amplitude on pump power.

Tailoring Secondary Coordination Sphere Effects in Single-metal-site Catalysts by Surface Immobilization of Supramolecular Cages.

Controlling the coordination sphere of heterogeneous single-metal-site catalysts is a powerful strategy for fine-tuning their catalytic properties but is fairly difficult to achieve. To address this problem, we immobilized supramolecular cages where the primary- and secondary coordination sphere are controlled by ligand design. The kinetics of these catalysts were studied in a model reaction, the hydrolysis of ammonia borane, over a temperature range using fast and precise online measurements generating high-precision Arrhenius plots.

Understanding the Oxidative Properties of Nickel Oxyhydroxide in Alcohol Oxidation Reactions.

The NiOOH electrode is commonly used in electrochemical alcohol oxidations. Yet understanding the reaction mechanism is far from trivial. In many cases, the difficulty lies in the decoupling of the overlapping influence of chemical and electrochemical factors that not only govern the reaction pathway but also the crystal structure of the formed oxyhydroxide.

Microscopic Proof of Photoluminescence from Mechanochemically Synthesized 1-Octene-Capped Quantum-Confined Silicon Nanoparticles: Implications for Light-Emission Applications.

Silicon nanoparticles (SiNPs) have been explored intensively for their use in applications requiring efficient fluorescence for LEDs, lasers, displays, photovoltaic spectral-shifting filters, and biomedical applications. High radiative rates are essential for such applications, and theoretically these could be achieved via quantum confinement and/or straining. Wet-chemical methods used to synthesize SiNPs are under scrutiny because of reported contamination by fluorescent carbon species.

Evidence of a 2D Electron Gas in a Single-Unit-Cell of Anatase TiO (001).

The formation and the evolution of electronic metallic states localized at the surface, commonly termed 2D electron gas (2DEG), represents a peculiar phenomenon occurring at the surface and interface of many transition metal oxides (TMO). Among TMO, titanium dioxide (TiO ), particularly in its anatase polymorph, stands as a prototypical system for the development of novel applications related to renewable energy, devices and sensors, where understanding the carrier dynamics is of utmost importance. In this study, angle-resolved photo-electron spectroscopy (ARPES) and X-ray absorption spectroscopy (XAS) are used, supported by density functional theory (DFT), to follow the formation and the evolution of the 2DEG in TiO thin films.