Photothermal Hydrogen Production Using Noble-Metal-Free Ti@TiO2 Core–Shell Nanoparticles under Visible–NIR Light Irradiation

Limiting resources of fossil fuels and environmental issues inevitably require more efficient utilization of solar energy. Photocatalytic production of hydrogen is identified as one of the most promising routes for developing clean and sustainable energy; however, engineering low-cost materials exhibiting high catalytic activity in the entire range of the solar spectrum is still a challenge. Here, for the first time, we report simple, easily scalable, and environmentally friendly synthesis of stable Ti@TiO2 core–shell nanoparticles exhibiting photocatalytic activity in hydrogen production under vis/NIR light irradiation without any noble metals. Stable to oxidation core–shell Ti@TiO2 nanoparticles have been obtained by the simultaneous actions of ultrasound and hydrothermal treatment on air-passivated titanium metal nanoparticles in pure water. The obtained material is composed of quasi-spherical Ti particles (20–80 nm) coated by 5–15 nm crystals of defect-free anatase with small amounts of rutile. In con...