The Superiority of TiO(2) Supported on Nickel Foam over Ni-Doped TiO(2) in the Photothermal Decomposition of Acetaldehyde.

Acetaldehyde decomposition was performed under heating at a temperature range of 25-125 °C and UV irradiation on TiO(2) doped by metallic Ni powder and TiO(2) supported on nickel foam. The process was carried out in a high-temperature reaction chamber, "The Praying Mantis(TM)", with simultaneous in situ FTIR measurements and UV irradiation. Ni powder was added to TiO(2) in the quantity of 0.5 to 5.0 wt%. The photothermal measurements of acetaldehyde decomposition indicated that the highest yield of acetaldehyde conversion on TiO(2) and UV irradiation was obtained at 75 °C. The doping of nickel to TiO(2) did not increase its photocatalytic activity. Contrary to that, the application of nickel foam as a support for TiO(2) appeared to be highly advantageous because it increased the decomposition of acetaldehyde from 31 to 52% at 25 °C, and then to 85% at 100 °C in comparison with TiO(2) itself. At the same time, the mineralization of acetaldehyde to CO(2) doubled in the presence of nickel foam. However, oxidized nickel foam used as support for TiO(2) was detrimental. Most likely, different mechanisms of electron transfer between Ni-TiO(2) and NiO-TiO(2) occurred. The application of nickel foam greatly enhanced the separation of free carriers in TiO(2). As a consequence, high yields from the photocatalytic reactions were obtained.