Modulating Aluminum Solvation with Ionic Liquids for Improved Aqueous-Based Aluminum-Ion Batteries.

Aqueous-based Al-ion batteries are attractive alternatives to Li-ion batteries due to their safety, high volumetric energy density, abundance, and recyclability. Although aluminum-ion batteries are attractive, there are major challenges to overcome, which include understanding the nature of the passive layer of aluminum oxide on the aluminum anode, the narrow electrochemical window of aqueous electrolytes, and lack of suitable cathodes. Here, we report using experiments in conjunction with DFT simulations to clarify the role of ionic liquids (ILs) in altering the Al solvation dynamics, which in turn affects the aluminum electrochemistry and aqueous-based battery performance significantly.

Spectroscopic Identification of Active Sites of Oxygen-Doped Carbon for Selective Oxygen Reduction to Hydrogen Peroxide.

The electrochemical synthesis of hydrogen peroxide (H O ) via a two-electron (2 e ) oxygen reduction reaction (ORR) process provides a promising alternative to replace the energy-intensive anthraquinone process. Herein, we develop a facile template-protected strategy to synthesize a highly active quinone-rich porous carbon catalyst for H O electrochemical production. The optimized PCC material exhibits remarkable activity and selectivity, of which the onset potential reaches 0.

Periodic corner holes on the Si(111)-7×7 surface can trap silver atoms.

Advancement in nanotechnology to a large extent depends on the ability to manipulate materials at the atomistic level, including positioning single atoms on the active sites of the surfaces of interest, promoting strong chemical bonding. Here, we report a long-time confinement of a single Ag atom inside a corner hole (CH) of the technologically relevant Si(111)-7×7 surface, which has comparable size as a fullerene C molecule with a single dangling bond at the bottom center. Experiments reveal that a set of 17 Ag atoms stays entrapped in the CH for the entire duration of experiment, 4 days and 7 h.

Synthesis, Structural Investigation, Hirshfeld Surface Analysis, and Biological Evaluation of -(3-Cyanothiophen-2-yl)-2-(thiophen-2-yl)acetamide.

In this study, a novel heterocyclic amide derivative, -(3-cyanothiophen-2-yl)-2-(thiophen-2-yl)acetamide (), was obtained by reacting 2-aminothiophene-3-carbonitrile with activated 2-(thiophen-2-yl)acetic acid in a -acylation reaction and characterized by elemental analyses, FT-IR, H and C NMR spectroscopic studies, and single crystal X-ray crystallography. The crystal packing of is stabilized by C-H···N and N-H···N hydrogen bonds. In addition, was investigated computationally using the density functional theory (DFT) method with the B3LYP exchange and correlation functions in conjunction with the 6311++G(d,p) basis set in the gas phase.

A comparative study on the stability of the furfural molecule on the low index Ni, Pd and Pt surfaces.

We present a comparative density functional theory investigation of the furfural (Ff) molecule on the low index Ni, Pd and Pt surfaces to understand its geometrical and electronic properties to gain mechanistic insights into the experimentally measured catalytic reactivities of these metal catalysts. We show that the number of metal states, which hybridize with the nearest C and O -orbitals of the Ff molecule, can be used to explain the stability of the Ff molecule on these surfaces. We find that the hybridization between atoms with higher electronegativity and the metal states plays a crucial role in determining the stability of these systems.

A computational investigation of the adsorption of small copper clusters on the CeO(110) surface.

We report a detailed density functional theory (DFT) study of the geometrical and electronic properties, and the growth mechanism of a Cu ( = 1-4) cluster on a stoichiometric, and especially on a defective CeO(110) surface with one surface oxygen vacancy, without using pre-assumed gas-phase Cu cluster shapes. This gives new and valuable theoretical insight into experimental work regarding debatable active sites of promising CuO/CeO-nanorod catalysts in many reactions. We demonstrate that CeO(110) is highly reducible upon Cu adsorption, with electron transfer from Cu clusters, and that a Cu cluster grows along the long bridge sites until Cu, so that each Cu atom can interact strongly with surface oxygen ions at these sites, forming stable structures on both stoichiometric and defective CeO(110) surface.

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface.

We present a combined density functional theory (DFT) and Kinetic Monte Carlo (KMC) study of the water gas shift (WGS) reaction on the Pd(100) surface. We propose a mechanism comprising both the redox and the associative pathways for the WGS within a single framework, which consists of seven core elementary steps, which in turn involve splitting of a water molecule followed by the production of an H-atom and an OH-species on the Pd(100) surface. In the following steps, these intermediates then recombine with each other and with CO leading to the evolution of CO, and H.

The electronic properties of Au clusters on CeO (110) surface with and without O-defects.

We use density functional theory with Hubbard corrections (DFT+U) to understand the local electronic properties of Au adatom and Au2 dimer adsorption on the CeO2 (110) surface. We show that, based on the initial geometries, we can observe Au species in a variety of charge states including Au+, Au-, Auδ- and Auδ+-Auδ-. We present a detailed discussion using Bader charge analysis and partial density of states to support our observations.

The adsorption of Cu on the CeO(110) surface.

We report a detailed density functional theory (DFT) study in conjunction with extended X-ray absorption fine structure (EXAFS) experiments on the geometrical and local electronic properties of Cu adatoms and Cu(ii) ions in presence of water molecules and of CuO nanoclusters on the CeO(110) surface. Our study of (CuO) clusters on CeO(110) shows that based on the Cu-O environment, the geometrical properties of these clusters may vary and their presence may lead to relatively high localization of charge on the exposed surfaces. We find that in the presence of an optimum concentration of water molecules, Cu has a square pyramidal geometry, which agrees well with our experimental findings; we also find that Cu(ii) facilitates water adsorption on the CeO(110) surface.

The reaction of formic acid with Raney copper.

The interaction of formic acid with Raney Cu proves to be complex. Rather than the expected generation of a monolayer of bidentate formate, we find the formation of a Cu(II) compound. This process occurs by direct reaction of copper and formic acid; in contrast, previous methods are by solution reaction.

Room temperature methoxylation in zeolites: insight into a key step of the methanol-to-hydrocarbons process.

Neutron scattering methods observed complete room temperature conversion of methanol to framework methoxy in a commercial sample of methanol-to-hydrocarbons (MTH) catalyst H-ZSM-5, evidenced by methanol immobility and vibrational spectra matched by ab initio calculations. No methoxylation was observed in a commercial HY sample, attributed to the dealumination involved in high silica HY synthesis.

Optimised photocatalytic hydrogen production using core-shell AuPd promoters with controlled shell thickness.

The development of efficient photocatalytic routines for producing hydrogen is of great importance as society moves away from energy sources derived from fossil fuels. Recent studies have identified that the addition of metal nanoparticles to TiO2 greatly enhances the photocatalytic performance of these materials towards the reforming of alcohols for hydrogen production. The core-shell structured Au-Pd bimetallic nanoparticle supported on TiO2 has being of interest as it exhibited extremely high quantum efficiencies for hydrogen production.