Benign Hydrothermal Synthesis of N‐doped TiO₂ and TiO₂‐CoS Nanostructures for Enhanced Visible‐Light Driven Photocatalytic Activity

Abstract

An efficient utilization of broad‐spectrum solar light to harvest energy for photocatalysis in a sustainable manner remains a critical challenge in the area of environmental remediation for a long time. To address this challenge, N‐doped TiO2‐CoS nanocomposite was successfully synthesized for the first‐time via a benign hydrothermal treatment adopting combination of doping, dimensional diversity and coupling strategies. The phase composition, surface morphology, nitrogen adsorption‐desorption analysis and photocatalytic degradation of Rhodamine B dye (RhB) in aqueous solution under simulated sunlight were well characterized and analyzed. The powder X‐ray diffraction patterns demonstrated the crystalline anatase phase of TiO2 in all photocatalysts. Scanning electron microscopy confirmed the formation of N‐doped TiO2 nanofibrous (NTNF) structure without phase alteration of TiO2 and demonstrated the co‐existence of spherical CoS particles that were randomly wrapped within the NTNF fibrous structure making the NTNF‐CoS nanocomposite. Nitrogen adsorption‐desorption analysis revealed higher specific surface area and larger pore volume of NTNF with mesoporous structure compared to those of N‐doped TiO2 nanoparticle (NTNP). The NTNF‐CoS nanocomposite showed superior photocatalytic degradation of RhB under visible light, which was predominantly ascribed to the synergistic effects of enhanced surface area, narrower band gap and efficient separation of photogenerated charge carriers. Thus, the NTNF‐CoS nanocomposite could be considered as a potential candidate for the removal or degradation of micro‐pollutant from the wastewater.

Preparation and Photocatalytic Studies on Nanocomposites of 4‐Hydroxylphenyl‐Substituted Corrole/TiO2 towards Methyl Orange Photodegradation

“…In order to overcome this drawback, many researches have been focused on modification of TiO 2 , such as the doping with metals (like Au, Pt, Fe, Mn, W, Cu or Cr) [7][8][9][10][11][12][13][14][15][16] or nonmetals (like P, F, C, S or N), [7][8][9][10]17] sensitization by other semiconductors (like g-CN, ZnO or Fe 3 O 4 ) [7][8][9][10] or organic dyes (like porphyrin, anthocyanin, curcumin or phthalocyanine). [18][19][20][21][22][23] Among them, organic dye sensitization has shown excellent capability compared with other methods in TiO 2 extent the ultra-violet light. [18][19][20][21][22][23] Corroles are 18π aromatic macrocyclic molecules.…”

“…[18][19][20][21][22][23] Among them, organic dye sensitization has shown excellent capability compared with other methods in TiO 2 extent the ultra-violet light. [18][19][20][21][22][23] Corroles are 18π aromatic macrocyclic molecules. [24][25][26][27][28] Due to the fascinating structure, corroles and their analogs including free base and metallated corroles can absorb intensively in the visible range of light, precisely in 400-450 nm and 500-700 nm, which represents the major constituents of the solar light.…”

“…However, the wide energy band gap makes TiO 2 suffer from its limited visible light absorption (less than 387 nm). In order to overcome this drawback, many researches have been focused on modification of TiO 2 , such as the doping with metals (like Au, Pt, Fe, Mn, W, Cu or Cr) [7–16] or nonmetals (like P, F, C, S or N), [7–10,17] sensitization by other semiconductors (like g‐CN, ZnO or Fe 3 O 4 ) [7–10] or organic dyes (like porphyrin, anthocyanin, curcumin or phthalocyanine) [18–23] . Among them, organic dye sensitization has shown excellent capability compared with other methods in TiO 2 extent the ultra‐violet light [18–23] …”

Synthesis of Core‐Shell Au@TiO2@C Nanoparticles and Their Photocatalytic Properties for the Degradation of Rhodamine B Under Simulated‐Solar Light

“…Over the past decades, a large number of researchers have done a lot of work to enhance photocatalytic properties of TiO 2 , [14][15][16] such as fabricating mesoporous nanostructure, [17] doping of inorganic elements and addition of narrower band gap semiconductors (CoS, [18] CuO, [19] g-C 3 N 4 [20] etc. ).One of the promising strategies is to introduce noble metals into TiO 2 nanoparticles such as, Au, [21] Ag [22] and Pt.…”