Water pollution has become a critical global concern due to the continuous release of toxic and persistent effluents from industrial, domestic, and leachate sources into natural water bodies. Securing a reliable supply of clean water is essential for human development, yet purification of contaminated water remains one of the most pressing environmental challenges of the modern era. Among the available strategies, photocatalytic mineralization has emerged as a promising technique for eliminating pollutants from wastewater. In this context, transition metalTransition metal-based layered double hydroxides (LDHs) have attracted significant attention as efficient photocatalysts, not only for the degradation of organic contaminants in water but also for their potential in sustainable energy applications. Their structural flexibility, compositional versatility, and tunable electronic properties enable precise adjustment of band gaps, greatly improving photocatalytic activity under visible light. Both binary and ternary LDHs have exhibited notable stability and high efficiency in pollutant degradation processes. Additionally, due to their unique physicochemical characteristics, transition metalTransition metal-based LDHs are increasingly being explored for photoelectrochemical (PEC) water splittingWater splitting, advancing the pursuit of clean and renewable energy solutions.