Hunting for high-performance photocatalysts to achieve efficient solar conversion is still far from ideal goals. Here, a kind of Janus structure, ASSiN2 (A = Cr, Mo, W) monolayers, is first proposed to explore their photocatalytic activity using the first-principles calculations. It is found that the Janus ASSiN2 monolayers are structurally stable and exhibit semiconductor behaviors with indirect bandgaps of 1.47, 2.86, and 3.02 eV, respectively. According to the comprehensive analysis of charge density difference, it is confirmed that an enhanced intrinsic electric field exists in the Janus structures, which could facilitate the separation of photogenerated carriers. Noteworthily, only the band-edge potentials of the WSSiN2 monolayer fully satisfy the redox conditions of photocatalytic water splitting. Meanwhile, the high electron mobility up to 1098.36 cm2·V–1·s–1 and strong visible-light absorption ability can be obtained in the WSSiN2 monolayer, indicating its great application potential in photocatalysis. The findings will offer reliable evidence for further developing 2D Janus materials as high-performance photocatalysts.

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Mesoporous TiO2–SiO2 films with remarkable self-cleaning capability were prepared by Sol–Gel methods and pressureless sintering. Here, the results show that the incorporation of 20 V% SiO2 onto the TiO2 films enhances the performance of anti-fog and self-cleaning. According to the SEM image, it is found that the TiO2 particles are dispersed by the SiO2, thus enlarging the specific surface area of the TiO2 particles. Therefore, super hydrophilicity and self-cleaning performance are promoted. Besides, the mesoporous structure is formed on the surface of the TiO2–SiO2 films after calcination. The mesoporous structure can improve the light utilization efficiency and the surface roughness of the films, thus promoting the performance of super hydrophilicity. Consequently, the mesoporous TiO2–SiO2 composite films as environmentally friendly coatings presented great potential in environmental governance.