| The development of multifunctional materials that can act simultaneously as efficient photocatalysts under natural sunlight irradiation and as effective adsorbents in the absence of light has attracted significant attention in recent years. Such dual-function systems offer promising strategies for sustainable environmental remediation, particularly in the removal of organic pollutants and hazardous dyes from water. Metal oxide semiconductors, including TiO₂, ZnO, and NiO, have emerged as leading candidates due to their strong adsorption ability, stability, and remarkable photocatalytic performance. The synergistic effect between adsorption and photocatalysis enhances pollutant removal efficiency by concentrating contaminants on the catalyst surface, thereby facilitating their subsequent degradation under irradiation. This work highlights the fundamental mechanisms underlying adsorption–photocatalysis coupling, recent advances in the synthesis and modification of metal oxide semiconductors, and the role of heterojunctions, dopants, and surface functionalization in optimizing performance. Moreover, challenges such as limited solar utilization and regeneration efficiency are critically studied. Future perspectives are proposed toward the design of cost-effective, durable, and environmentally friendly materials that can exploit both adsorption and photocatalytic pathways for water purification under real environmental conditions. |
