The Role of the Ferroelectric Polarization in the Enhancement of the Photocatalytic Response of Copper-Doped Graphene Oxide–TiO₂ Nanotubes through the Addition of Strontium

Abstract

To evaluate the potential role of in situ formed Sr−Ti−O species as a ferroelectric component able to enhance the photocatalytic properties of an adjacent TiO 2 semiconductor, Cu-doped/graphene oxide (GO)/TiO 2 nanotubes (TiNTs) composites (with 0.5 wt % Cu and 1.0 wt % GO) have been synthesized while progressive amounts of strontium (up to 1.0 wt %) were incorporated at the surface of the composite through incipient wetness impregnation followed by post-thermal treatment at 400 °C. The different resulting photocatalytic systems were then first deeply characterized by means of N 2 adsorption−desorption measurements, X-ray diffraction (XRD), UV−vis diffuse reflectance (UV−vis DR), Raman and photoluminescence (PL) spectroscopies, and scanning electron microscopy (SEM) (with energy-dispersive X-ray (EDX) spectroscopy and Z-mapping). In a second step, optimization of the kinetic response of the Sr-containing composites was performed for the formic acid photodegradation under UV irradiation. The Sr-containing Cu/GO/TiNT composites were then fully characterized by electrochemical impedance spectroscopy (EIS) for their dielectric properties showing clearly the implication of polarization induced by the Sr addition onto the stabilization of photogenerated charges. Finally, a perfect correlation between the photocatalytic kinetic evaluation and dielectric properties undoubtedly emphasizes the role of ferroelectric polarization as a very valuable approach to enhance the photocatalytic properties in an adjacent semiconductor.

Ciprofloxacin Electrochemical Sensor Using Copper–Iron Mixed Metal Oxides Nanoparticles/Reduced Graphene Oxide Composite

“…GO can be reduced based on chemical or thermal reduction to rGO, in which a portion of the functional groups is removed. rGO provides the electrical properties of a semiconductor and is a good sensitive element or charge-transfer promotor in a sensor device. , GO can be composited with metals and metal oxides and becomes a mixed metal oxides/rGO composite. Side reactions involve the conversion of GO to rGO due to reduction reactions occurring during chemical and thermal treatment.…”

The Effect of Nitrogen- and Oxygen-Containing Functional Groups on C2H6/SO2/NO Adsorption: A Density Functional Theory Study

“…Chemically binding atoms and atomic groups other than carbon, the carbon atoms within this graphite layer form a diverse array of surface functional groups that significantly impact its adsorption performance [10,11]. The oxygen-containing functional group of coal-based graphene acts as an electron acceptor and transporter, and plays an important role in enhancing charge transfer and hindering the recombination of electron-hole pairs [12,13]. N doping remodels the local electron density of graphene surfaces and greatly promote adsorption with various interactions [9].…”