The adsorption-photocatalytic synergism of LDHs-based nanocomposites on the removal of pollutants in aqueous environment: A critical review

Layered double hydroxides (LDHs) as highly operable nanomaterials in terms of chemical composition, structural morphology, and energy band gaps, demonstrating excellent absorption-photocatalytic synergism in achieving in-situ degradation of pollutants in the aqueous environment. However, the current research on the adsorption-photocatalytic process of LDHs is still limited. To promote the development and application of LDHs in the adsorption-photocatalysis process, this work reviews the structural characteristics and directional regulation strategies of LDHs with different dimensions. It introduces the removal performance of LDHs-based nanocomposites for various pollutants in aqueous environment, and analyzes the degradation mechanism and crucial processes from three aspects: adsorption, photocatalytic, and adsorption-photocatalytic synergy. Moreover, the review focuses on modification strategies for targeted enhancement of the absorption and photocatalytic properties of LDHs, future development challenges, and application prospects. This review aims to provide basic insights for the design of LDHs-based nanocomposites and their in-depth research and development applications in the water treatment field based on the adsorption-photocatalysis integration effect.