Concomitant synthesis of highly crystalline Zn–Al layered double hydroxide and ZnO: Phase interconversion and enhanced photocatalytic activity

Metal oxide/hydroxide with hierarchical nanostructures has emerged as one of the most promising materials for their unique, attractive properties and feasibility of applications in various fields. In this report, a concomitant synthesis of crystalline zinc aluminum layered double hydroxide (ZnAl-LDH) nanostructure and ZnO is presented using Al substrate as template. Studies on interconversion of ZnO to LDH phase in bulk solution under hydrothermal conditions produced Al-doped ZnO (AZO) in one case, and in other, it improves the crystallinity of LDH film templated on Al substrate. In presence of Al salt, the self-limiting growth nature of plate LDH turned to non-self-limiting. Materials obtained during phase transition, AZO in bulk solution and crystalline porous ZnAl-LDH on substrate, have been demonstrated as effective photocatalysts for decomposition of congo red in aqueous medium.

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► A facile hydrothermal method for concurrent synthesis of crystalline LDH phase and ZnO.
► Phase transitions from pure LDH to pure ZnO.
► Self-limiting growth of plate LDH turned to non-self-limiting in presence of Al salt.
► Formation of Al-doped ZnO and sequential increase in crystallinity of substrate LDH phase.
► Both Al-doped ZnO and nano LDH substrate samples showed superior photocatalytic activity.