Anyone know about Efficient Photocatalyst group (for photodegradation or Hydrogen production) that has Low albedos as compared to Degussa P25? (e.g. albedos of ~0.6, whereas TiO2 based photocatalysts is about ~0.9)
Hi Patricio
Recently graphitic carbon nitride (g-C3N4) has attracted a lot of attention as a low cost photocatalyst for CO2 reduction and hydrogen production. Perhaps that would satisfy your requirement for a photocatalyst within an albedo ~0.6.
Best
Geoff
In the past we prepared titania-silica powders with a low albedo. The size of the powders strongly affects the albedo. Generally, the larger the particles the lower the albedo.The volume/surface average dimension of our powders was about 10 micrometers, so they were much larger than Degussa P25 and the albedo was evaluated to be around 0.2-0.25. We tested it for the decolorization of an aqueous solution of a dye. If you are interested probably I could find the original "recipe" to obtain those particles. However, larger particles imply that the rate of degradation per unit mass of photocatalyst becomes lower, because of the unfavorable surface to volume ratio. I wonder why you want to work with low albedo particles. A high scattering increases the radiant energy losses by backscattering, but probably the drawbacks of operating at large size of the particles are more important.
Dear Dr. Patricio Javier Valades-Pelayo
About g-C3N4-based photocatalysts, please refer to the attached papers published by my research group.
Hello Dr. @Aziz and @Giovanni, thanks for the information. I will surely look into the references given. @Giovanni , do you have any reference regarding the low albedo particles synthesized?
Dear Patricio,
Our experience with TiO2-based materials is similar to yours and they typically render albedo numbers around 0.8-0.9 in the UV region. However, when studying Nb-doped TiO2 or others materials active under sunlight--type illumination, the average albedo is significantly lower and above the band gap you can have values near 0.6.
Dear Patricio,
please find attached a copy of a work where the preparation procedure of the silica-titania powders is illustrated.
Regards,
Giovanni
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