With the rapid development of the social economy and urbanization, urban environmental pollution has become increasingly serious. Green buildings that meet national standards have become a current focus. In order to improve the waterproof and self-cleaning properties of prefabricated building exterior walls, environmental purification technology is applied to prepare coatings with photocatalytic effects for cement-based materials of prefabricated building exterior walls. The results showed that when the titanium to silicon ratio was 10:1 and 10:2, the degradation rates of the material reached 99.42% and 99.01%, respectively. The adhesion strength of photocatalytic materials with different dosages was 1.80 MPa, 1.97 MPa, 1.74 MPa, and 1.75 MPa, respectively, which significantly improved the adhesion performance compared with the blank group. The water absorption of photocatalytic coatings was less than 0.10 kg/(m2 × h0.5), indicating good waterproof effect. In summary, the preparation of photocatalytic coating materials and their application in prefabricated buildings can effectively reduce maintenance cost, extend the service life of buildings, and provide scientific support and reference for green building projects. The innovation of the research lies in the first combination of environmental purification technology with prefabricated building exterior wall materials, proposing a new type of photocatalytic coating that can effectively improve the durability and self-cleaning ability of buildings. This provides a practical and feasible solution for reducing maintenance costs and extending the service life of buildings, and provides important scientific support and reference for the development of green building projects.

This study proposes a cement-based photocatalytic coating material based on prefabricated building exterior walls. The coating material is prepared using a solvent method by combining semiconductor photocatalyst TiO
2 with porous SiO
2 powder. The durability properties of the prepared N-TiO
2/SiO
2 photocatalytic coating, including photocatalytic performance, water absorption, stability, and adhesion, are analyzed. The results showed that the degradation rate of the photocatalytic coating reached a maximum of 96.81%, the adhesion strength reached a maximum of 1.97 MPa, and the moisture content reached a maximum of 9.35%. In addition, the degradation rate of the photocatalytic coating decreased by less than 10%, significantly better than the blank group’s 23.55%, demonstrating good stability.
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