Temperature-controlled synthesis of MnNb2O6 by an easy sol-gel method and investigation of its photocatalytic properties.

Author Motta, Fabiana Villela da; Andrade Neto, Nivaldo Freire de; Duarte, Willian Nascimento; Silva, Ubiratan Correia; Delmonte, Maurício Roberto Bomio
Publisher

Journal of the Indian Chemical Society

Date

2025-11

Keywords

Sol-gel synthesis

Heterostructures

MnNb2O6

Photocatalysis

Citation
Abstract

This study explores a facile synthesis of MnNb2O6 at 650, 800, and 950 °C and its photocatalytic activity in methylene blue (MB) degradation under UV light. XRD and Rietveld refinement showed secondary Mn2O3 and Nb2O5 phases at lower temperatures, with pure MnNb2O6 forming at 950 °C. FESEM revealed that higher calcination temperatures produced denser, prismatic particles. Photocatalytic tests showed low activity at pH 7 and pH 3 due to dominant adsorption, but significantly improved efficiency at pH 11, attributed to increased ∙OH radical formation. Scavenger experiments indicated enhanced photocatalysis with silver nitrate (e− scavenger) and citric acid (h+ scavenger), especially with silver nitrate. EPR analysis confirmed greater ∙OH and ∙O2− radical generation in the heterostructured sample (MNO650) than in the pure phase (MNO950), suggesting that structural defects and heterojunctions in MNO650 reduce electron-hole recombination, thus enhancing photocatalytic performance

URIhttps://repositorio.ufrn.br/handle/123456789/66136
CollectionsCT - DEMAT - Artigos publicados em periódicos