Optical and Photocatalytic Properties of Carbon-Activated Anatase with Spherical Shape of Aggregates

Abstract

Carbon-doped anatase with spherical shape of aggregates has been synthesized by the developed precursor technique with the use of Ti(OCH 2 CH 2 ) 2 as a precursor. The synthesized samples of the general composition TiO 2-y C y :nC with different carbon content have been tested for the photocatalytic activity in the oxidation reaction of water-dissolved hydroquinone during irradiation in ultraviolet and visible light. It was shown that the optical and photocatalytic properties of TiO 2-y C y :nC depend strongly on the concentration of carbon. The first-principles calculations of the electronic band structure and optical absorption spectra have been carried out. The probabilities of formation of carbon for oxygen substitutional defects and interstitial defects (implantation of carbon atoms into interstitial sites) have been analyzed. The calculations performed allowed us to determine the dominating type of defects responsible for absorption and photocatalytic activity of carbon-doped anatase in the visible spectral region.

Synthesis, structure and spectroscopic characteristics of Ti(O,C)2/carbon nanostructured globules with visible light photocatalytic activity

“…For the synthesis of the precursor aggregates with different morphologies, titanium tetrabutoxide Ti(C 4 H 9 O) 4 and ethylene glycol HOCH 2 CH 2 OH reagents were taken in various volumetric ratios. The details of this solvathermal technique were described in our prior work [31].…”

“…In order to evaluate the stability of the samples during photocatalysis, the cycle of bringing one and the same catalyst into contact with the solution was repeated three times. The method of conducting the photocatalysis experiment is described in detail elsewhere [31,35].…”

“…It should be noted that a number of solvothermal and hydrothermal routes can be applied for the morphology-controlled synthesis of such precursor mediate micro-aggregates [27][28][29][30]. One-step carbonisation of mediate Ti-glycolate precursors has proven its efficiency, and we currently utilise it for the synthesis of composite aggregates with globule morphology and visiblelight photocatalytic activity [31]. When considering these approaches, the first research objective is to understand how the synthesis conditions will affect the morphology of the asprepared composite TiO 2 /C aggregates, their specific surface area as well as the structure of globules comprising different carbon states.…”

Synthesis, spectral, optical and photocatalytic properties of vanadium- and carbon-doped titanium dioxide with three-dimensional architecture of aggregates

“…For example, using titanium glycolate Ti(OCH 2 CH 2 O) 2 and solid solutions based thereon of the general composition Ti 1-x M x (OCH 2 CH 2 O) 2 as precursors, it is possible to synthesize both pure and transition-element and carbon-doped titanium dioxide in the form of nanodispersed solid solutions TiO 2-y C y , Ti 1-x M x O 2 , Ti 1-x M x O 2-y C y and nanocomposites TiO 2-y C y :nC, Ti 1-x M x O 2-y C y :nC with pre-assigned concentration of impurity elements and controlled dimensional and morphological characteristics of particles [25][26][40][41][42][43][44][45][46]. In most cases, the morphology and dimensions of precursor crystals depend on the method of their production.…”

“…By varying the ratio of the reaction mixture components including titanium tetrabutoxide Ti(C 4 H 9 O) 4 and ethylene glycol, as well as the synthesis conditions, we obtained samples of titanium glycolate Ti(OCH 2 CH 2 O) 2 with threedimensional near-spherical architecture of crystal aggregates [46]. As a result of thermolysis in air or inert atmosphere, these spherical aggregates undergo a pseudomorphic transformation into TiO 2 , TiO 2-y C y and TiO 2-y C y :nC particles.…”