Ag-doped TiO2 photocatalysts with effective charge transfer for highly efficient hydrogen production through water splitting

Abstract

Abstract The development of efficient metal doped semiconductors for solar energy harvesting to produce hydrogen has attracted significant attention. Herein, the H2 generation over Ag-doped TiO2 photocatalyst, synthesized using a simple and cost-effective method based on chemical reduction, was reported. The Ag/TiO2 exhibited an absorption peak in the visible region and the reduction of the bandgap to 2.5 eV due to surface plasmonic resonance (SPR). X-ray photoelectron spectroscopy revealed the presence of oxygen vacancies and 11% of Ag in Ti–Ag–O phase. The effect of reaction time and photocatalyst loading in the absence and presence of sacrificial reagents (alcohols and sulfur) on water splitting was studied and compared the activity of Ag/TiO2 with that of bare TiO2. The H2 production rate of 23.5 mmol g−1 h−1 (with an apparent quantum yield of 19%), over 1.5Ag/TiO2, was the highest ever reported so far. The observed higher activity could mainly be attributed to the existence of oxygen vacancies and the Ti–Ag–O phase. The photocatalyst was stable for three consecutive cycles in both the presence and absence of sacrificial reagents. This study offers new insights into the rational design of metal-support hybrid structures for hydrogen production through photocatalytic water splitting.