Accelerated self-cleaning by Cu promoted semiconductor binary-oxides under low intensity sunlight irradiation

作者：Rtimi S; Pulgarin C; Sanjines R; Kiwi J^*

来源：Applied Catalysis B: Environmental , 2016, 180: 648-655.

DOI：10.1016/j.apcatb.2015.06.047

• TiO2-ZrO2 binary oxides
• Self-cleaning photocatalysis
• Cu intra-gap states
• Band-gap of various TiO2-ZrO2-Cu
• Interfacial charge transfer mechanism (IFCT)

Uniform adhesive TiO2-ZrO2 films co-sputtered on polyester (PES) under low intensity sunlight irradiation discolored methylene blue (MB) within 120 min. The discoloration kinetics was seen to be accelerated by a factor four by TiO2-ZrO2-Cu containing similar to 0.01% Cu, as determined by X-ray fluorescence (XRF). TiO2-ZrO2-Cu also increased also accelerated by a factor the discoloration of MB compared to TiO2/Cu(PES). MB discoloration was also monitored under visible light in the solar cavity by using a 400 nm cutoff filter. Photocatalyst surfaces were characterized by spectroscopic methods showing the film optical absorption and by X-ray photoelectron spectroscopy (XPS), the surface atomic percentage concentration up to 120 nm (similar to 600 layers). The band-gaps of TiO2-ZrO2 and TiO2-ZrO2-Cu were estimated for films co-sputtered for different times. By Fourier transform attenuated infrared spectroscopy (ATR-FTIR), the systematic shift of the predominating nu(s)(CH2) vibration-rotational MB bands was monitored up to complete MB discoloration under low intensity solar simulated light. Evidence is presented for the OH center dot generation by TiO2-ZrO2-Cu participating in the self-cleaning mechanism. The photo-induced interfacial charge transfer (IFCT) on the TiO2-ZrO2-Cu is discussed in terms of the electronic band positions of the binary oxides and Cu intra-gap states. This study presents the first evidence for a Cu-promoted composed of two binary oxide semiconductors accelerating the self-cleaning performance.

• 出版日期2016-1