Ag-doped TiO2 photocatalysts with effective charge transfer for highly efficient hydrogen production through water splitting. (24th January 2020)

• Record Type: Journal Article
• Authors: Gogoi, Devipriya; Namdeo, Ashutosh; Golder, Animes Kumar; Peela, Nageswara Rao
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 4(2020)
• Page Start: 2729
• Page End: 2744
• Publication Date: 2020-01-24
• Subjects: Photocatalytic water splitting -- Renewable energy -- Bandgap reduction -- Hydrogen production; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.11.127
• Languages: English
• ISSNs: 0360-3199

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. Graphical abstract: Image 1 Highlights: The Ag/TiO2 synthesized by chemical reduction, lowers the band gap of TiO2 . XPS confirms oxygen vacancies and Ag in both Ag 0 and Ti–Ag–O phases. The Ti–Ag–O phase promotes efficient charge transfer and separation. Oxygen vacancies and Ti–Ag–O in Ag/TiO2 enhances the photoreduction of water to H2 . Remarkable H2 production of 23.5 mmol g −1 h −1 over Ag doped TiO2 .