Effects of MnII and EuIII Cation Exchange in Sepiolite‐Titanium Dioxide Nanocomposites in the Photocatalytic Degradation of Orange G

Abstract

AbstractTwo primary mechanisms of titanium dioxide (TiO2) efficiency inhibition in ultraviolet (UV)‐driven photocatalytic reactions are the high recombination rate and sintering. To address these challenges, TiO2 nanocrystals were grown in‐situ onto sepiolite modified with MnII and EuIII ions. The resulting nanocomposites were characterized and evaluated for photocatalytic activity for Orange G (OG) degradation under UV irradiation. Resultant reduction in activity over Mn‐sepiolite‐TiO2 is attributed to charge‐carrier scavenging by unstable Mn and adsorption‐mediated chromophore protection by Mn‐oxyhydroxide. Dye removal over Eu‐sepiolite‐TiO2 was only slightly more efficient than over the control despite relevant Eu concentrations; potentially related to inhibited TiO2‐Eu interfacial synergy and superoxide radical scavenging. The results of this investigation corroborate prior observations that substrate cation‐exchange results in unpredictable behavior of the cations introduced during subsequent fabrication steps which may be of benefit or detriment to the final material.