Electrochemical characterization of praseodymium centers in Pr x Zr1−x O2 zirconias using electrocatalysis and photoelectrocatalysis

Abstract

The voltammetry of nanoparticles and scanning electrochemical microscopy are applied to characterize praseodymium centers in tetragonal and monoclinic zirconias, doped with praseodymium ions (Pr x Zr 1−x O 2 ), prepared via sol-gel routes. Doped zirconia nanoparticles were synthesized by a sol-gel liquid-phase route and characterized by different techniques, including X-ray diffraction powder pattern, ultraviolet-visible diffuse reflectance spectroscopy, infrared spectroscopy, and transmission electron microscopy (TEM). Gels annealed at around 400°C yielded tetragonal Pr x Zr 1−x O 2 phases. The monoclinic forms of Pr-doped ZrO 2 were obtained by annealing at temperatures higher than 1,100°C. TEM micrographs proved that the size of the nanoparticles produced was dependent on their crystalline form, around 15 and 60 nm for tetragonal and monoclinic, respectively. The electrochemical study confirmed that a relatively high content of praseodymium cation was in the chemical state (IV), i.e., as Pr 4+ , in both zirconia host lattices. The catalytic and photocatalytic effects of Pr 4+ centers located in the monoclinic zirconia lattice on nitrite reduction and oxygen evolution reaction were studied.

Synthesis, characterization and electrochemical properties of iron-zirconia solid solution nanoparticles prepared using a sol–gel technique

“…The experimental procedure used in the preparation of Fe-containing zirconia gels, Fe x Zr 1Àx O 2 , with compositions in the range 0 r x r 0.15, was previously described in the preparation of other metal-doped zirconia. 12,29 Basically the procedure is as follows. To a mixture of acetylacetone (acacH, C 5 H 8 O 2 ) and absolute ethanol (EtOH, C 2 H 5 OH) kept under N 2 inert atmosphere were added the required amounts of zirconium n-propoxide (ZnP, Zr(OC 3 H 7 ) 4 ) and iron acetylacetonate (Fe(acac) 3 , FeC 15 H 24 O 6 ).…”

“…VMP is a solid-state electrochemical technique developed by Scholz et al [25][26][27] which provides information on the chemical and mineralogical compositions of sparingly soluble solids. In previous reports, we have already used this technique for obtaining chemical and structural, 13,28 and electrocatalytic information 28,29 and analytical applications 11,12 of V-and Pr-doped zirconia.…”

Gold-Supported Nanostructured NiFeCoPr Hydroxide as a High-Performance Supercapacitor Electrode and Electrocatalyst toward the Oxygen Evolution Reaction

“…Generally, the enhanced electrochemical performance of NiFeCoPrO-Au/NF can be attributed to the incorporation of the Pr dopant, , the support of the gold bottom coating, and the ultrathin amorphous nanostructure of the active materials. ,− …”

Electrochemistry of Iron-Doped Zircon and Zirconia Materials and Electrocatalytic Effects on Nitrite Oxidation and Reduction

“…Solid-state electrochemical experiments were performed by mechanically transferring small amounts of the solid specimens to the surface of paraffin-impregnated graphite electrodes following the procedures already reported. 22,23 Cyclic (CV) and square wave voltammetric measurements (SWV) were performed at 298 ± 1 K in a conventional three-electrode cell under argon atmosphere using a CH I660 potentiostat coupled to a conventional three-electrode cell with Pt auxiliary electrode and AgCl (3M NaCl)/Ag reference electrode. NaNO 2 (Merck) in concentrations between 1.0 mM and 0.15 M and 0.50 M acetic acid/sodium acetate (HAc/NaAc, Panreac) buffer (pH 4.75), 0.10 M potassium phosphate buffer (pH 7.00) and 0.10 M NaCl were used as supporting electrolytes.…”

“…14 Previous results confirmed that preparation of nanoparticulate V-and Zr-doped zirconias, with relatively narrow particle size distribution, is achieved by controlled hydrolysis and condensation of metal acetylacetonate and zirconiumn-propoxide mixtures. 15,16 In this context, solid state electrochemistry, using the voltammetry of microparticles (VPM) methodology, [17][18][19] can offer information on the oxidation state, coordinative environment 20 and electrocatalytic properties [21][22][23] of this kind of materials. In particular, application of VMP to doped zirconias and zircons has been revealed as a useful strategy for enhance selectivity toward electrochemical reduction/oxidation of selected analytes, as indicated in previous works.…”