Near Infrared Light‐to‐Heat Conversion for Liquid‐Phase Oxidation Reactions by Antimony‐Doped Tin Oxide Nanocrystals

Abstract

Effective utilization of the sunlight for chemical reactions is pivotal for dealing with the growing energy and environmental issues. So far, much effort has been focused on the development of semiconductor photocatalysts responsive to UV and visible light. However, the near infrared and infrared (NIR-IR) light occupying ~50 % of the solar energy has usually been wasted because of the low photon energy insufficient for the band gap excitation. Antimony doping into SnO 2 (ATO) induces strong absorption due to the conduction band electrons in the NIR region. The absorbed light energy is eventually converted to heat via the interaction between hot electrons and phonons. This Concept highlights the photothermal effect of ATO nano-crystals (NCs) on liquid-phase oxidation reactions through the NIR light-to-heat conversion. Under NIR illumination even at an intensity of ~0.5 sun, the reaction field temperature on the catalyst surface is raised 20-30 K above the bulk solution temperature, while the latter is maintained near the ambient temperature. In some reactions, this photothermal local heating engenders the enhancement of not only the catalytic activity and selectivity but also the regeneration of catalytically active sites. Further, the photocatalytic activity of semiconductors can be promoted. Finally, the conclusions and possible subjects in the future are summarized.

Fundamentals and Applications of Gold Nanoparticle-Based Plasmonic Photocatalysts for Water Purification

“…Thus, the specification of the detailed information about the oxidation sites and the modification by the promoters can be important subjects for further improving the photocatalytic activity. Au NPs have very strong absorption coefficient, and in the Au NP-based plasmonic photocatalysts, the photon energy directly unavailable for the redox reactions can also be used to accelerate the reactions by increasing the local temperature around the reaction fields. , Utilization of this plasmonic photothermal effect would be important for not only solar-to-fuel conversion but also for environmental purification. The expensiveness of Au severely hampers the wide application of Au NP-based plasmonic photocatalysts for environmental purification.…”