No abstract

No abstract

No abstract

Solid solutions BaLn(BiPb)O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; 0.00 ≤ x ≲ 0.15) have been prepared under 850 °C. They all crystallize in space group P1 at room temperature. XPS data indicate that the valences are 5+ and 3+ for bismuth, 4+ and 2+ for lead, and 3+ or 4+ for lanthanide. Some of them are superconductors. The superconductive transition temperature T decreases or remains constant with an increase of Ln in the sample when Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. However, T first decreases, then increases, and finally decreases when Ln = Ce, Pr, which is due to the corresponding sample changes from hole-doped to electron-doped superconductors with an increase of Ce or Pr in the sample.

Photoelectrocatalysts are robust materials for the production of energy through different ways such as water splitting. Narrow optical band gaps and high overpotentials are limiting the development of photoelectrocatalysts. In this study, a series of Co1–(x+y)Fe x Mn y WO4 solid solutions of cobalt tungstate codoped with iron and manganese have been synthesized hydrothermally. The synthesized solid solutions have been characterized by powder XRD, UV–visible spectra, cyclic voltammetry (CV), and linear sweep voltammetry (LSV). They all crystallize in a wolframite-type monoclinic crystal system with space group P2/c. Doping of iron and manganese leads to narrowing of the optical band gap of Co1–(x+y)Fe x Mn y WO4 from 2.60 to 2.04 eV. The electrocatalytic activity toward oxygen evolution reaction of all of the samples has been evaluated through LSV measurements. It is found that the sample named C5, which is codoped with manganese and iron, has the lowest onset potential and needs the lowest overpotential to attain the targeted 5 mA cm–2 and standard 10 mA cm–2 current densities as compared with all other synthesized samples. This study shows that the synthesized tungstates can be good candidates for the photoelectrocatalytic oxygen evolution reaction.

Solid solution EuMn1−xCuxO3−δ (0 ≤ x ≤ 0.316) crystallizes in the space group Pnma and shows magnetic transitions from about 52 to 20 K.

No abstract

No abstract