NaNbO/NaTaO Superlattices: Cation-Ordering Improved Band-Edge Alignment for Water Splitting and CO Photocatalysis.

Perovskite oxide heterostructures have been extensively investigated for their excellent photocatalytic properties. Here, through hybrid density functional theory calculations, we systematically investigate the formation of NaNbO-NaTaO (NBO-NTO) heterostructures. The sequential cations replacement in the superlattices reveals the Nb-Ta ratio range that allows the effective formation of heterostructures, which occurs through a spontaneous polarization mechanism induced by the electrostatic potential discontinuity in the interface.

Modulation of band alignment with water redox potentials by biaxial strain on orthorhombic NaTaO thin films.

Photocatalysis-assisted water splitting using semiconductor materials greatly depends on the bandgap size and the alignment of band edges relative to the reaction potentials. We used ab initio computational methods to show that the biaxial strain on [100]-oriented orthorhombic NaTaO thin films grants the modulation of surface states, favoring either the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER), which basically rules the perovskite photocatalytic performance. Under compression, the outermost TaO and TaO polyhedra become more distorted, and electrostatic repulsion increases the energy of Ta 5d surface states.

Strain modulation of TaO planarity in tantalates ultrathin films: surface states engineering.

Ultrathin films of perovskites have attracted considerable attention once they fit in numerous applications. Over the years, controlling and tuning their properties have been attainable when biaxial strain is applied. Through ab initio DFT calculations, (110) ultrathin (Na,K)TaO films were submitted to biaxial tensile and compressive strain.

Structural and electronic properties of NaTaO cubic nanowires.

Sodium tantalate nanostructures have been classified among the best materials to conduct photocatalytic reactions. Therefore, understanding the relationship between nanoscale surface phenomena and photocatalytic properties is of fundamental importance. We performed Density Functional Theory calculations to investigate how chemically different facets may affect intrinsic properties of NaTaO cubic nanowires.

Cardiolipin Structure and Oxidation Are Affected by Ca at the Interface of Lipid Bilayers.

Ca-overload contributes to the oxidation of mitochondrial membrane lipids and associated events such as the permeability transition pore (MPTP) opening. Numerous experimental studies about the Ca/cardiolipin (CL) interaction are reported in the literature, but there are few studies in conjunction with theoretical approaches based on calculations. In the present study, the lipid fraction of the inner mitochondrial membrane was modeled as POPC/CL large unilamellar vesicles (LUVs).

Dynamic covalent bond from first principles: Diarylbibenzofuranone structural, electronic, and oxidation studies.

A structure that can self-heal under standard conditions is a challenge faced nowadays and is one of the most promising areas in smart materials science. This can be achieved by dynamic bonds, of which diarylbibenzofuranone (DABBF) dynamic covalent bond is an appealing solution. In this report, we studied the DABBF bond formation against arylbenzofuranone (ABF) and O reaction (autoxidation).

pH-Dependent Synthesis of Anisotropic Gold Nanostructures by Bioinspired Cysteine-Containing Peptides.

In the present study, alkaline peptides AAAXCX (X = lysine or arginine residues) were designed based on the conserved motif of the enzyme thioredoxin and used for the synthesis of gold nanoparticles (GNPs) in the pH range of 2-11. These peptides were compared with free cysteine, the counterpart acidic peptides AAAECE and γ-ECG (glutathione), and the neutral peptide AAAACA. The objective was to investigate the effect of the amino acids neighboring a cysteine residue on the pH-dependent synthesis of gold nanocrystals.

Origin of FM ordering in pristine micro- and nanostructured ZnO.

An unexpected presence of ferromagnetic (FM) ordering in nanostructured nonmagnetic metal oxides has been reported previously. Though this property was attributed to the presence of defects, systematic experimental and theoretical studies to pinpoint its origin and mechanism are lacking. While it is widely believed that oxygen vacancies are responsible for FM ordering, surprisingly we find that annealing as-prepared samples at low temperature (high temperature) in flowing oxygen actually enhances (diminishes) the FM ordering.