Ag/Ag2SO3 plasmonic catalysts with high activity and stability for CO2 reduction with water vapor under visible light
2016
Wang, Da | Yu, Yan | Zhang, Zhipeng | Fang, Huiying | Chen, Jianmeng | He, Zhiqiao | Song, Shuang
The conversion of CO₂ into useful raw materials for fuels and chemicals by solar energy is described using a plasmonic photocatalyst comprised of Ag supported on Ag₂SO₃ (Ag/Ag₂SO₃) fabricated by a facile solid-state ion-exchange method and subsequent reduction with hydrazine hydrate. The optimum molar ratio of Ag⁰/Ag⁺ was 5 %. Visible light irradiation (>400 nm) of the Ag/Ag₂SO₃ powder in the presence of CO₂ and water vapor led to the formation of CH₄ and CO with a quantum yield of 0.126 %, and an energy returned on energy invested of 0.156 %. The Ag/Ag₂SO₃ retained high catalytic activity after ten successive experimental cycles. The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy with energy-dispersive X-ray analysis, UV/Vis absorption spectroscopy, and Brunauer-Emmett-Teller analyses, as well as photocurrent action spectroscopy. It is proposed that the photocatalytic activity of the catalysts is initiated by energy conversion from incident photons to localized surface plasmon resonance oscillations of silver nanoparticles. This plasmonic energy is transferred to the Ag₂SO₃ by direct electron transfer and/or resonant energy transfer, causing the separation of photogenerated electron/hole pairs.
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