Exploring PbZn₄SiTeO₁₀ Toward New Colored Compounds, Host for Red Luminescence, and as an Electrocatalyst for Oxygen...

The silicate compound, PbZn₄SiTeO₁₀, was investigated for its structural flexibility and the ensuing properties. The compounds were prepared by conventional solid-state synthesis and the phase purity was confirmed by the powder x-ray diffraction (PXRD). Raman spectroscopy studies indicated the expected bands. XPS analysis was useful in arriving at the oxidation states in the substituted compounds. The substitution of transition metal ions (Co²⁺, Cu²⁺, and Ni²⁺) in place of Zn²⁺ ions in tetrahedral coordination results in new colored compounds, which were characterized by optical absorption spectroscopy with the help of ligand-centered/charge-transfer bands together with the spin-allowed d-d transitions. The white compounds were found to exhibit a good near-infrared (NIR) reflectivity (∼80%), which is comparable to the standard TiO₂ compound. The white compounds also exhibit reasonable dielectric constant values with low loss. Substitution of Eu³⁺ ions at the Pb²⁺ sites (pentagonal bi-pyramidal coordination) results in a deep red emission, with the maximum emission intensity at 7% Eu³⁺ ions substitution. The Co compound, PbZn₃CoSiTeO₁₀, exhibits good performance toward oxygen evolution reaction (OER) with values comparable to RuO₂. The present study explored the structurally characterized PbZn₄SiTeO₁₀ compound toward new colored variants, NIR-reflectivity studies, dielectric behavior, red emission, and electrocatalytic water oxidation (OER).