Preparation of N-TiO₂/SiO₂ composites by solvothermal method and their photocatalytic properties

Abstract

In order to improve the visible light catalytic activity of titanium dioxide (TiO2) and ensure its long-term stability on the surface of concrete, an N-TiO2/SiO2 composite was prepared using tetrabutyl titanate, nitric acid, and modified SiO2 nanospheres as the precursors by a solvothermal method. The effect of nitric acid on the phase composition, morphology and photoelectric properties of the synthesized photocatalytic composites was systematically studied by various characterization methods. The results show that the optimum nitric acid/butyl titanate volume ratio is 1/6. The nitrogen-doped TiO2 nanoparticles were uniformly dispersed on the surface of spherical SiO2 with a diameter of 200 nm. The degradation rate of simulated pollutants (RhB) with pH 5 and 7 exceeded 95% within 30 minutes and the catalytic effect remained excellent after five repetitions without much weakening. The excellent visible photocatalytic performance can be attributed to the doping of N replacing part of the oxygen atoms in TiO2, forming the energy level of N 2p at the O 2p energy level and reducing the TiO2 energy band gap to 2.99 eV. At the same time, the better dispersion of N-TiO2/SiO2 prepared by this new synthesis method also plays an important role in the improvement of visible light photocatalytic activity.

Mechanistic Understanding in Manipulating Energetics of TiO2 for Photocatalysis

“…In addition to cation- and anion-doped TiO 2 , composite materials are frequently designed for enhancing the photocatalytic activity of TiO 2 . − For example, composite materials consisting of activated carbon (AC) and multiwalled carbon nanotube (MWCNT) and TiO 2 can be used for photocatalytic CO 2 reduction and hydrogen generation. − TiO 2 nanoparticles (NPs) can also be coated uniformly on the MWCNT to form a core–shell structure. This type of structure is beneficial for more interfacial interactions and instant charge carrier migration.…”

The synergistic effect of N-doped TiO2-SiO2 nanocatalysts and peroxydisulfate towards improving Bisphenol A photodegradation efficiency

“…The catalytic efficiency exhibits a trend of decreasing with the increase of N element doping. This could be referred to the appropriate amount of N incorporation that promotes the effective separation of photo-generated charges, but excessive N elements lead to compounding of photogenerated electrons during the transport process [9]. pairs was reduced as the reaction between the electrons and PDS [13].…”

“…To overcome this challenge, elemental doping, especially non-metal doping is one of the effective approaches which are proposed to upgrade the optical properties of TiO2-SiO2 composites. Therein, the non-metallic element N is the most widely utilized element because it is close to the O element in both atomic radius and elemental position, and some of the O atoms can be substituted by N atoms [9]. The N-doped TiO2-SiO2 composites are proven to have good activity in degrading effectively many types of pollutants such as azo dyes [9], antibiotics [10], aromatics [11], etc.…”

“…Therein, the non-metallic element N is the most widely utilized element because it is close to the O element in both atomic radius and elemental position, and some of the O atoms can be substituted by N atoms [9]. The N-doped TiO2-SiO2 composites are proven to have good activity in degrading effectively many types of pollutants such as azo dyes [9], antibiotics [10], aromatics [11], etc. Consequently, Ndoped TiO2-SiO2 is a potential candidate drawing great deal of concern for removing contaminants in polluted water.…”