Novel hierarchical architectures of Sb2WO6: template-free hydrothermal synthesis and photocatalytic reduction property for azo compound

Novel hierarchical architectures of Sb2WO6 are synthesized successfully by a simple hydrothermal process without any organic solvent or surfactant. The physicochemical properties of the as-prepared products are characterized in detail. Interestingly, the morphologies of Sb2WO6 could be selectively controlled by adjusting pH values of the reactive solutions. The tuft-like, cockscomb-like, and flower-like hierarchical architectures are obtained at pH = 1, 3, and 5, respectively. Based on the time-dependent experimental results, a possible growth mechanism is proposed, which reasonably follows a synergy interaction of reaction–crystallization and dissolution–recrystallization processes. The photocatalytic activities of the novel hierarchical Sb2WO6 are evaluated by the decomposition of azo compounds for the first time. Results show that the as-prepared samples exhibit the excellent photocatalytic activity and universality for the reduction of azo compounds. The conversion of methyl orange reaches 98 % after 140 min of light irradiation. HPLC–MS indicates that the selectivity of 4-aminobenzene sulfonic acid is over 99 %.