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

Abstract

a b s t r a c tUniform adhesive TiO 2 -ZrO 2 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 TiO 2 -ZrO 2 -Cu containing ∼0.01% Cu, as determined by X-ray fluorescence (XRF). TiO 2 -ZrO 2 -Cu also increased also accelerated by a factor the discoloration of MB compared to TiO 2 /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 (∼600 layers). The band-gaps of TiO 2 -ZrO 2 and TiO 2 -ZrO 2 -Cu were estimated for films co-sputtered for different times. By Fourier transform attenuated infrared spectroscopy (ATR-FTIR), the systematic shift of the predominating s (CH 2 ) vibration-rotational MB bands was monitored up to complete MB discoloration under low intensity solar simulated light. Evidence is presented for the OH • generation by TiO 2 -ZrO 2 -Cu participating in the self-cleaning mechanism. The photo-induced interfacial charge transfer (IFCT) on the TiO 2 -ZrO 2 -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.

Tratamiento superficial con nanopartículas base silicio inducido durante el curado: Efecto en la durabilidad de materiales base cemento portland

“…A corto o mediano plazo, esta interacción provoca el deterioro de las ECR, generando además gastos anuales entre 18 a 21 mil millones de USD en rehabilitaciones o reparaciones debido a la corrosión del acero de refuerzo (Barnat-Hunek et al, 2016;Khaloo et al, 2016). Más del 50% de estas ECR presentan problemas de deterioro a causa de la alta permeabilidad o baja calidad del concreto (Fajardo, et al, 2015;Rtimi et al, 2016), que favorece al mecanismo de transporte de agentes agresivos como al dióxido de carbono (CO2), ion cloruro (Cl-) y sulfatos (SO4-2), siendo éstos, la principal causa de deterioro en las ECR (Achal et al,2015;Trapote-Barreira et al, 2014). Sin embargo, debemos recordar que las propiedades importantes, tales como la resistencia, la permeabilidad y la durabilidad, están ligadas directamente con la porosidad en el concreto (Fajardo et al, 2015;Hou et al, 2015;Hou et al, 2016;Kupwade-patil et al, 2016).…”

Cu-decorated Raschig-TiO 2 rings inducing MB repetitive discoloration without release of Cu-ions under solar light

“…The position of the potential energy level of the Cu-intra-gap states lies between the TiO 2 vb (3.1 eV) and the TiO 2 cb (À0.1 eV) and can be estimated to be close to 0.15 eV [19]. The Cu 1+/2+ on the TiO 2 under band-gap irradiation would work as an electron acceptor enhancing MB-degradation [20]. Fig.…”

“…Reaction (2) is much faster than the CuO dissolution [19,20], shown in Eq. EDTA is used generally as a hole scavenger in TiO 2 photocatalysis.…”

Recent Developments in Accelerated Antibacterial Inactivation on 2D Cu-Titania Surfaces under Indoor Visible Light

“…inactivation. These studies have shown a drastic enhancement of the bacterial inactivation kinetics of E. coli when Cu was added to binary-oxides in percentages from 0.01% (decoration) up to 1% (doping) [119,127,173]. A variety of TiO2-Cu preparations and the evaluation of their activity for diverse applications is an area of current interest [129][130][131]174].…”