New Approach of the Oxidant Peroxo Method (OPM) Route to Obtain Ti(OH)₄ Nanoparticles with High Photocatalytic Activity under Visible Radiation

Abstract

Environmental problems related to the generation of wastewater contaminated with organic compounds and the emissions of pollutants from fuel burning have become major global problems. Thus, there is a need for the development of alternative and economically viable technologies for the remediation of the affected ecosystems. Therefore, this work describes the preparation and characterization of a Ti(OH)4 catalyst with the modified surface for application in the photodegradation of organic compounds (methylene blue (MB) dye and the drug amiloride (AML)) and in the artificial photosynthesis process. Characterization results reveal that peroxo groups on the surface of the catalyst had a great influence on the optical properties of the Ti(OH)4 and consequently in its photocatalytic property. This catalyst showed a high photocatalytic activity for the degradation of organic pollutants under visible radiation, reaching approximately 98% removal of both the dye and the drug in 150 min of reaction. In addition, the catalyst presented a great potential for the reduction of CO2 under ultraviolet (UV) radiation when compared to P25, which is a classic catalyst used in photocatalytic processes. The highest photocatalytic activity can be attributed to the strong visible light absorption, due to the narrow band gap, and the effective separation of photogenerated electron-hole pairs caused by the peroxo groups on the Ti(OH)4 surface.

Modified Titanium Dioxide as a Potential Visible-Light-Activated Photosensitizer for Bladder Cancer Treatment

“… 18 Since Ti(OH) 4 is a mixture of anatase and rutile, the amount of peroxide groups is consumed to produce ROS; 22 however, the material has almost 1 mol of peroxide molecule per gram of nanoparticles, which is a huge amount of oxygen that allows the system to be active during several cycles without a significant decrease of reactivity. 18 , 19 …”

“…Ti(OH) 4 was synthesized using the oxidant peroxo method (OPM), a wet-chemical route that allows titanium atoms at the surface to bond to two oxygen atoms, forming a peroxide group, which gives its yellow color. 18 In this method, 3 mL of titanium isopropoxide was added to 40 mL of hydrogen peroxide and heated to 80 °C to form a yellow gel. The gel was dried at 60 °C for 24 h to form a Ti(OH) 4 powder.…”

“… 18 , 19 The covalent binding of these peroxide groups to the surfaces of nanoparticles shifts the band gap to about 2.3 eV, 18 , 19 hence allowing the Ti(OH) 4 to absorb visible light and present equivalent photocatalytic activity when exposed to UV light and about 90% greater activity if compared to common TiO 2 . 18 Furthermore, it was demonstrated that the contact of Ti(OH) 4 with water can produce OH* radicals even after several photodegradation cycles. 18 Therefore, the use of Ti(OH) 4 to treat nonmuscle invasive bladder cancer can be extremely advantageous compared to the PS used thus far.…”

“… 18 Furthermore, it was demonstrated that the contact of Ti(OH) 4 with water can produce OH* radicals even after several photodegradation cycles. 18 Therefore, the use of Ti(OH) 4 to treat nonmuscle invasive bladder cancer can be extremely advantageous compared to the PS used thus far.…”

Preparation of Bi-based heterostructures through the one-pot method with the potential to photocatalytic applications

“…[3,4] Typically, metal oxides such as TiO2 and ZnO are the most popular materials used as photocatalysts. [5][6][7][8] These materials are activated only under UV radiation, so they have low efficiency driven by solar radiation, making large-scale applications inviable. [9] Thus, there has been a growing interest in developing functional materials capable of absorbing a larger part of the solar spectrum, as active catalysts under visible radiation, as this represents 43% of sunlight, against only 5% for UV radiation.…”