Fabrication and Characterization of a Marine Wet Solar Cell with Titanium Dioxide and Copper Oxides Electrodes

One of the effective ways of utilizing marine environments is to generate energy, power, and hydrogen via the effect of photocatalysts in the seawater. Since the ocean is vast, we are able to use its large area, but the power generation system must be of low cost and have high durability against both force and corrosion. In order to meet those requirements, this study focuses on the fabrication of a novel marine wet solar cell composed of a titanium dioxide photoanode and a copper oxide photocathode. These electrodes were deposited on type 329J4L stainless steel, which possesses relative durability in marine environments. This study focuses on the characterization of the photocatalytic properties of electrodes in seawater. Low-cost manufacturing processes of screen-printing and vacuum vapor deposition were applied to produce the titanium dioxide and copper oxides electrodes, respectively. We investigated the photopotential of the electrodes, along with the electrochemical properties and cell voltage properties of the cell. X-ray diffraction spectroscopy (XRD) of the copper oxides electrode was analyzed in association with the loss of photocatalytic effect in the copper oxides electrode. Although the conversion efficiency of the wet cell was less than 1%, it showed promising potential for use in marine environments with low-cost production. Electrochemical impedance spectroscopy (EIS) of the cell was also conducted, from which impedance values regarding the electrical properties of electrodes and their interfaces of charge-transfer processes were obtained. This study focuses on the early phase of the marine wet solar cell, which should be further studied for long-term stability and in actual marine environmental applications.

NEW ANTIMICROBIAL STRATEGIE USING COMPOSITIONS WITH PHOTOCATALYTIC PROPERTIES

The paper describes the studies started by an inter-disciplinary team in finding a disinfection method using a coating with photocatalytically activated antimicrobial properties by visible spectrum radiation. An own method of preparation led to the obtaining of a photocatalytic pigment based on copper-doped titanium dioxide to move the activation spectrum to the visible range. The preparation method was designed so as to allow transposition into industrial production. The demonstration and measurement of the photocatalytic effect for certification as an industrial product was done based on an adapted method, starting from two existing standards. A washable paint containing the photocatalytic pigment was tested "in situ", the results demonstrating the reduction of microbial load. The paper is based on current knowledge about light-activated antimicrobiological agents (LAAs) in an attempt to further the study of visible spectrum radiation, which in combination with a series of photosensitizers excited by this radiation, have the role of generating photocatalytic reactions with disinfection effect.

Photodegradation of Aquaculture Antibiotics Using Carbon Dots-TiO2 Nanocomposites

In this work, carbon dots (CD) were synthesized and coupled to titanium dioxide (TiO2) to improve the photodegradation of antibiotics in aquaculture effluents under solar irradiation. Oxolinic acid (OXA) and sulfadiazine (SDZ), which are widely used in aquaculture, were used as target antibiotics. To prepare nanocomposites of CD containing TiO2, two modes were used: in-situ (CD@TiO2) and ex-situ (CD/TiO2). For CD synthesis, citric acid and glycerol were used, while for TiO2 synthesis, titanium butoxide was the precursor. In ultrapure water (UW), CD@TiO2 and CD/TiO2 showed the largest photocatalytic effect for SDZ and OXA, respectively. Compared with their absence, the presence of CD@TiO2 increased the photodegradation of SDZ from 23 to 97% (after 4 h irradiation), whereas CD/TiO2 increased the OXA photodegradation from 22 to 59% (after 1 h irradiation). Meanwhile, in synthetic sea salts (SSS, 30‰, simulating marine aquaculture effluents), CD@TiO2 allowed for the reduction of SDZ’s half-life time (t1/2) from 14.5 ± 0.7 h (in absence of photocatalyst) to 0.38 ± 0.04 h. Concerning OXA in SSS, the t1/2 remained the same either in the absence of a photocatalyst or in the presence of CD/TiO2 (3.5 ± 0.3 h and 3.9 ± 0.4 h, respectively). Overall, this study provided novel perspectives on the use of eco-friendly CD-TiO2 nanocomposites for the removal of antibiotics from aquaculture effluents using solar radiation.

Preparation and properties of ice cream flowers Ce/TiO2 photocatalyst

TiO2 composite photocatalysts with doping amounts of Ce (0.5%Ce/TiO2, 1%Ce/TiO2, 2%Ce/TiO2, 3%Ce/TiO2 and 5%Ce/TiO2)were synthesized via a sol-gel method.The structure and morphology of the prepared composites were characterized by XRD, SEM, DRS, XPS. At the same time, the photocatalytic effect of the composite on rhodamine B (RhB) solution under simulated visible light irradiation was explored.The results indicated that the crystal of powder catalyst was anatase type TiO2, and the directional aggregation of Ce/TiO2 composite photocatalyst showed ice cream flowers-shaped structure.The photocatalysis activity was the best when Ce doping amounts were 3%.The degradation rate of RhB was 96% in 120 min, which was 50% higher than pure TiO2.Hydroxyl radical (⋅OH) played a leading role in the whole photodegradation reaction system, and its contribution rate was about 66.4%.