A sea cucumber-like nanoporous TiO₂ modified by bimetal Pt–Au through the dealloying for water splitting

Bimetal Pt–Au modifying nanoporous TiO₂ composites are prepared by dealloying. X-ray diffraction is used to determine the phase constitution. The specific surface area and mesoporous pores are measured by Brunauer-Emmett-Teller. X-ray photoelectron spectroscopy, photoluminescence spectroscopy, UV–Vis diffuse reflectance spectroscopy and Raman spectroscopy are employed to analyse the mutual synergy between Pt and Au. The hydrogen generation rate is measured to determine the photocatalytic performance. The results reveal that TiO₂ is the anatase structure and possess a sea cucumber-like morphology with a large specific surface area. The hydrogen generation rate is 1.745 mmol h⁻¹ g⁻¹ for the dealloyed Al₉₂Ti_7.86Pt_0.04Au_0.1 ribbons under the full spectrum irradiation. This value is 29.6 times, 4.4 times and 1.8 times those of the dealloyed Al₉₂Ti₈, Al₉₂Ti_7.9Au_0.1, and Al₉₂Ti_7.96Pt_0.04 ribbons, respectively. The above results indicate that the addition of a small amount of Au and Pt significantly enhances the photocatalytic activity for H₂ production. The Au promotes the absorption of visible light, and Pt serve as an electron sink for effective electron-hole pairs separation during the photocatalytic process. It is a feasible and an effective strategy to take full advantages of respective virtues of noble metals and their strong interactions to enhance photocatalytic activity.