Download or read book Photochemical and Photothermal Reduction of Carbon Dioxide for Solar Fuels Production written by Abdinoor Abdullahi Jelle and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract Catalytic conversion of greenhouse gas carbon dioxide to value-added chemicals and fuels powered by solar energy is envisioned to be a promising strategy to realize both energy security and environmental protection. This work demonstrates that earth abundant, low cost nanomaterials based on silicon and iron can be used to harvest both light and heat energy from the sun to reduce CO2 and generate solar fuels. Herein, we have demonstrated that ruthenium supported ultra-black silicon nanowires can drive the Sabatier reaction both photochemically and photothermally where both incident photons absorbed by and heat generated in the black silicon nanowires accelerate the photomethanation reaction. This allows the reaction to be activated at ambient temperatures removing the need for external heating that could cause sintering, mechanical degradation and eventual catalyst deactivation and therefore improves the overall energy efficiency of the process. Additionally, we have shown that the rate of photomethanation is greatly enhanced when highly dispersed nanocrystalline RuO2 is chemically deposited onto the black silicon nanowires support. Furthermore, we have demonstrated that other silicon structures such as three-dimensional silicon photonic crystals can be used as an efficient support for CO2 hydrogenation. Unlike other insulating supports, these silicon nanostructured supports are particularly attractive for solar-powered catalysis because, with a band-gap of 1.1 eV, they can potentially absorb 80% of the solar irradiance. Moreover, they exhibit excellent absorption strengths and low reflective losses across the entire solar spectral wavelength range of the ultraviolet, visible and near-infrared portion of the solar spectrum. Finally, we demonstrated a comprehensive comparative study of the physical, electronic, and photocatalytic properties of ironoxyhydroxide (FeOOH) polymorphs by studying the extent of methylene blue photodegradation. This work led to the transformation of these FeOOH polymorphs into magnetite (Fe3O4) which effectively reduced CO2 to CO via the reverse water gas shift (RWGS) reaction.