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

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 similar to 50 % of the solar energy has usually been wasted because of the low photon energy insufficient for the band gap excitation. Antimony doping into SnO2 (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 nanocrystals (NCs) on liquid-phase oxidation reactions through the NIR light-to-heat conversion. Under NIR illumination even at an intensity of similar to 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.

Automated summary

Effective utilization of sunlight for chemical reactions is crucial for addressing energy and environmental issues. Current efforts in the development of semiconductor photocatalysts focus on UV and visible light responsiveness, while near infrared and infrared light, which account for about 50% of solar energy, is often wasted due to insufficient photon energy for band gap excitation. However, antimony doping into SnO2 induces strong absorption in the NIR region, enabling conversion of absorbed light energy to heat through the interaction between hot electrons and phonons. This concept highlights the potential of ATO nanocrystals for photothermal enhancement of liquid-phase oxidation reactions.