Improved photoelectrochemical properties of TiO2 nanotubes doped with Er and effects on hydrogen production from water splitting.

Erbium-doped TiO2 nanotubes (Er-TiO2 NTs) are prepared with a combination of anodization and electrochemical deposition using various proportions of erbium and adjusting the time of the process. The surface characterization techniques and electrochemical analysis are applied to study the physicochemical and photoelectrochemical (PEC) properties of the as-prepared photocatalysts. Er-TiO2 NTs have crystal sizes of about 24-30 nm, smaller than those of pure TiO2 NTs, and contain only the anatase phase. Er-TiO2 NTs exhibit an effective photo-conversion efficiency (PCE) of 1.58% and a photosensitivity of 115.06. The modified sample are also more efficient (photocurrent density of 6.64 mAcm-2 at a bias potential of 1.5 V vs. Hg/HgO) compare to pure TiO2 NTs. The photocatalytic activity of the Er-TiO2 NTs are evaluated in a hydrogen generation reaction, and the results show hydrogen production of ∼17.39 µmolhr-1cm-2. Further experiments demonstrate that Er-TiO2 NTs successfully degrade methylene blue, with the most active sample reaching 85% photocatalysis after 180 min. This study shows that doping conditions significantly affect the optical and electrical properties of the resulting material, and that the current electrochemical approach to metal doping can be used for efficient and stable PEC water splitting.

Data on the characterization of Raney nickel powder and Raney-nickel-coated electrodes prepared by atmospheric plasma spraying for alkaline water electrolysis.

The data presented in this article are related to the research article entitled: "Electrochemical characterization of Raney nickel electrodes prepared by atmospheric plasma spraying for alkaline water electrolysis" (Kim et al., 2018). This article describes the characterization of raw Ni-Al alloy and Raney Ni powders via X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS), and presents the EDS data of the prepared electrodes.

Ammonium fluoride-activated synthesis of cubic δ-TaN nanoparticles at low temperatures.

Cubic delta-tantalum nitride (δ-TaN) nanoparticles were selectively prepared using a K2TaF7 + (5 + k) NaN3 + kNH4F reactive mixture (k being the number of moles of NH4F) via a combustion process under a nitrogen pressure of 2.0 MPa. The combustion temperature, when plotted as a function of the number of moles of NH4F used, was in the range of 850°C to 1,170°C. X-ray diffraction patterns revealed the formation of cubic δ-TaN nanoparticles at 850°C to 950°C when NH4F is used in an amount of 2.0 mol (or greater) in the combustion experiment. Phase pure cubic δ-TaN synthesized at k = 4 exhibited a specific surface area of 30.59 m2/g and grain size of 5 to 10 nm, as estimated from the transmission electron microscopy micrograph. The role of NH4F in the formation process of δ-TaN is discussed with regard to a hypothetical reaction mechanism.