Ag+/ Ag-tio2 nano hollow spheres (Ag+/ Ag-tio2 nano hollow spheres, i.e. Ag+/Ag-HTS) were prepared by deposition of silver sulfide on the surface of TiO2/ polystyrene composites and calcination in air.

The results showed that the prepared Ag+/ AG-HTS had visible light catalytic degradation activity of methyl orange, and the catalytic degradation efficiency increased with the decrease of the initial concentration of methyl orange. The formation of Schottky barrier helps to transfer more holes to the surface of the material and enhance its photocatalytic efficiency. Ag+ on the surface facilitates the removal of electrons and prevents photoexcited electrons from recombining with photoexcited holes.

With the increase of silver sulfide deposition, the visible light catalytic activity of Ag+/Ag-HTS increased, and the photocatalytic degradation of methyl orange showed the kinetic characteristics of pseudo-first-order reaction. Using 25% Ag+/ AG-HTS photocatalyst, the degradation rate of methyl orange reached 70.6% under visible light irradiation for 2 hours.

Conclusion

Ag+/ AG-HTS visible light catalyst can be prepared by modifying the surface of HTS with Ag+/Ag. For the samples with different amount of silver sulfide deposition, the order of photocatalytic MO degradation ability is as follows: 10%< 15%< 20%< 25%, the photocatalytic activity increased with the increase of silver sulfide deposition.

The joint modification of Ag+ and Ag on the surface helps to remove the electrons transferred from the Ag surface by HTS. However, the catalytic activity of Ag+/Ag-HTS was higher than that of pure HTS only when the amount of Ag sulfide was higher than 15%. With the increase of the initial concentration of MO, the visible catalytic activity of Ag+/Ag-HTS decreases rapidly compared with HTS catalyst. Using Schottky barrier generation and co-modification to remove carried electrons is an effective method to enhance photoexcited electron and photoexcited hole separation and improve photocatalytic activity. The "cage effect" of the hollow structure is conducive to improving the catalytic efficiency.