Room temperature sequential ionic deposition (SID) of Ag2S nanoparticles on TiO2 hierarchical spheres for enhanced catalytic efficiency

Abstract

Porous TiO₂ hierarchical spheres with high surface area synthesized via a solvothermal method were successfully modified with an Ag₂S co-catalyst by a sequential ionic deposition (SID) method at room temperature. The presence of Ag₂S facilitated efficient charge separation, thus reducing recombination and enhancing the photocatalytic activity of the photocatalyst. The enhanced photocatalytic performance was demonstrated by water splitting where hydrogen (H₂) gas was produced at an evolution rate of 708 μmol h⁻¹ g⁻¹ and methyl orange was degraded with a rate constant of 0.018 min⁻¹. This is the first time that photocatalytic water splitting using a suspension system has been demonstrated on a Ag₂S/TiO₂ hierarchical heterostructure and the material shows stability in its photocatalytic performance despite being recycled several times. The composite material presents properties which are highly promising for the generation of clean energy and environmental clean up applications.