Sulfate-Anchored Hierarchical Meso–Macroporous N-doped TiO₂: A Novel Photocatalyst for Visible Light H₂ Evolution

Abstract

Visible light-active hierarchical meso−macroporous S,N-modified TiO 2 has been synthesized through a precipitation and deposition method and characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, BET surface area, X-ray photo electron spectroscopy, and photoluminescence studies. The finding demonstrates that N exists in the form of N−Ti−O in the crystal lattice of TiO 2 ; however, sulfate (S 6+ ) is bidentately coordinated on the surface of TiO 2 . The existence of sulfate maintains the morphology as well as enhances the surface area, decreases the crystallite size, shifts the optical absorption toward the red end, acts as co-catalyst, and facilitates the photogenerated charge carriers. Moreover, the presence of a hierarchical meso−macroporous frame enhances visible light-harvesting properties as well as favors easy channelization of electrons, which effectively reduces the charge recombination. The photocatalytic activity has been evaluated through H 2 evolution. The observed enhancement in activity for 4SNTP-400 has been explained on the basis of a synergistic combination of anionic−cationic species, hierarchical meso−macroporous frames with high surface area, and high crystallization of anatase phase with small crystallite size and low PL intensity, which makes the system more potential toward visible light activity.

A facile in situ approach to fabricate N,S-TiO2/g-C3N4 nanocomposite with excellent activity for visible light induced water splitting for hydrogen evolution

“…Another peak observed at 288.2 eV is the characteristic peak for N-C-N coordination in g-C 3 N 4 . [12][13][14] The absence of the S 2p signal for Tu (g-C 3 N 4 ) confirms a lack of S species. 38 Fig.…”

“…1, two pronounced diffraction peaks have been noticed for pure g-C 3 N 4 . 12,13 In all of the xTuT nanocomposites, there was no typical peak observed for g-C 3 N 4 and this might be due to the low crystallinity and ultrathin layered structures of g-C 3 N 4 . 27.41 can be indexed as (002) and corresponds to the inter planer stacking reflection of graphitic like structures with an interlayer distance of d = 0.326 nm.…”

“…1,2 Unfortunately, two of its major drawbacks hinder its potential applications: one is its large band gap energy (i.e. [10][11][12][13][14][15][16] Recently, promising results have been achieved through the coupling of wide band gap semiconductors with narrow gap ones. Therefore, researchers are striving towards the development of titania based visible light active photocatalysts.…”

WS2 as an Effective Noble-Metal Free Cocatalyst Modified TiSi2 for Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

“…However, TiO 2 as a photocatalyst for practical use is restricted by the low visible-light absorption and fast photogenerated electron-hole recombination [7][8][9]. To develop a novel, efficient, and cost-effective visible-light-driven photocatalyst is indispensable to realize the aim of applicable solar energy conversion [10][11][12].…”

Preparation of Mn-doped ZrO2/TiO2 photocatalysts for efficient degradation of Rhodamine B

“…[19][20][21][22] In previous studies, TiO 2 coupled with zirconia has been investigated extensively in degradation of organic compounds. [23] However, due to the large band gap of ZrO 2 , there is almost no charge transfer between TiO 2 and ZrO 2 . It impedes the efficient separation of charge carriers and inhibits the corresponding photocatalytic performance.…”