Effect of chemical potential on the structural modification of titanate- based photocatalysts: Fast dye degradation efficiency and adsorption power

In this work, the impact of the chemical potential of sodium hydroxide concentration was evaluated in the synthesis of titanate-based photocatalysts prepared by the microwave-assisted hydrothermal method. The materials were characterized by techniques that made it possible to unveil their structural, morphological, and electronic properties, corroborating the formation of a heterojunction of sodium titanate (Na2Ti6O13) and hydrated hydrogen titanate (H2Ti3O7 center dot H2O). The results demonstrated that the increased chemical po-tential of NaOH caused an ionic exchange between Na+ and H+ ions, making the H2Ti3O7 center dot H2O phase more stable. The oriented attachment (OA) growth mechanism was predominant, resulting in nanoparticles with nanosheet-like morphology. The photocatalytic efficiency of the materials was tested for the discoloration of Rhodamine B (RhB) and Methylene Blue (MB) dyes. The photocatalyst with the best efficiency showed a half-life time for RhB discoloration of only 5 min and a high capacity of adsorption in the MB medium (similar to 90% in 10 min). The details of the nanoparticle growth mechanism, the charge transport in the heterojunction, and the stability and reusability of the materials were clarified. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This study evaluated the impact of sodium hydroxide concentration on the synthesis of titanate-based photocatalysts. The results showed that increasing the chemical potential of NaOH stabilized the H2Ti3O7 center dot H2O phase and induced the growth of nanoparticles with nanosheet-like morphology. The photocatalyst exhibited efficient discoloration of Rhodamine B and high adsorption capacity for Methylene Blue.