Visible and direct sunlight induced H2 production from water by plasmonic Ag-TiO2 nanorods hybrid interface

- Plasmonic effect at Ag-TiO2 nanojunction for sensitizing 457 nm light absorption.
- Improved photocurrent density of elongated Ag-TiO2 nanorod hybrid composites.
- H2 production from H2O by monochromatic light irradiation in the visible wavelength.
- Ag-TiO2 nanorod exhibited improved H2 production under direct sunlight exposure.

This report signifies the synthesis of TiO2 nanorods (TNR ~79 nm) and nanospheres (TNS ~19 nm) and their Ag loaded counterparts AgTNR and AgTNS for the photocatalytic hydrogen production from water under monochromatic visible and direct sunlight. The Ag-TNR nanohybrid junction was sensitized at a matching monochromatic wavelength of 457 nm and sunlight to produce ~90 µmol and 105 µmol of gas, respectively, increase in the efficiency is explained due to the surface plasmon (SPR) effect of Ag nanoparticles and is also correlated to fluorescence quenching (due to better charge distribution along larger nano-interface), crystal structure and surface area (146 m2 g−1) of fabricated AgTNR nanocomposite. The elongated morphology of AgTNR led to the effective distribution of charge along larger interface resulting in the increase of photocurrent density (0.01 mA/cm2) which boosts the reaction rate. Plasmonic metal (Ag) activated with matching wavelength to SPR produces an electric field and the TiO2 present in the proximity encounters these effects results in the formation of Schottky barrier, the SPR effect is also more towards Ag-TiO2 interface which results in the ejection of electron towards the conduction band of TNR.This study demonstrated that Ag nanoparticles loaded lengthy TiO2 nanorods (~79 nm) exhibited highly improved H2 production (90 μmol) from water relative to TiO2 nanospheres (~19 nm) due to the plasmonic effect at 457 nm light irradiation that also exhibited better H2 production (105 μmol) rate under direct sun light (8 h) exposure.

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