Superior self-cleaning surfaces via the synergy of superhydrophobicity and photocatalytic activity: Principles, synthesis, properties, and applications

Self-cleaning surfaces are attractive and desirable owing to their unique benefits to the environment, energy, and labor-saving for various promising practical applications. Superior self-cleaning surfaces can be achieved by the synergy of superhydrophobicity and photocatalytic activity to overcome the individual inherent limitations, which have been substantially developed over the last decade. To our best knowledge, this is the first critical review focusing exclusively on the dual self-cleaning surfaces with the coexistence of superhydrophobicity and photocatalytic activity. First, the self-cleaning principles are reviewed from three aspects of superhydrophobic self-cleaning mechanisms, photocatalytic self-cleaning mechanisms, and importantly their synergies. Second, in addition to one-pot construction, the synthesis strategies of dual self-cleaning surfaces are summarized into three main steps, involving surface roughness generation, low-surface-energy material modification, and photocatalyst integration. Third, three key properties of dual self-cleaning surfaces are demonstrated, namely superhydrophobicity, photocatalytic activity, and durability. Fourth, diverse applications are proposed, including superior self-cleaning, antifouling, antibacterial, oil/water separation, etc. Last but not least, the future perspectives of dual self-cleaning surfaces are pointed out. This review is believed to provide comprehensive information on the fabrication and application of self-cleaning surfaces for long-term use driven by nature.