Intelligent Hydrated-Sulfate Template Assisted Preparation of Nanoporous TiO₂ Spheres and Their Visible-Light Application

Abstract

Hydrated metal sulfates (MSO(4)·xH(2)O, M = Zn, Fe, Co, Mg, etc.) were proposed to be intelligent templates to solvothermally synthesize nanoporous TiO(2) spheres with tunable chamber structures from hollow to solid and hybrid compositions. During the reaction, hydrated sulfate serves simultaneously as spherical template, water supplier, and composition controller, and it can be easily removed by washing. The as-prepared anatase TiO(2) spheres were evidenced to contain highly crystallized TiO(2) nanocrystals hybridized with a small amount of metal oxide from the hydrated sulfate. The formation mechanism of the hollow spheres involves the self-conglobation of hydrated sulfate, the hydrolysis of tetrabutyl titanate on the spherical templates, and the subsequent process of solvothermal crystallization. The proposed hydrated-sulfate assisted solvothermal (HAS) strategy was demonstrated to be widely applicable to various systems. When applied to visible-light photocatalysis, the hybrid TiO(2) spheres exhibit excellent photocatalytic performance, benefiting from the reduced charge recombination rate contributed by the heterojunctions of TiO(2) and the hybridized metal oxides.

Synthesis and applications of porous non-silica metal oxide submicrospheres

“…255 In another example, TiO 2 shells were prepared on hydrated sulfate templates of ZnSO 4 Á7H 2 O in ethanol. 256 The spherical templates of ZnSO 4 Á7H 2 O in ethanol that were formed acted as sites for deposition of titanium species. Moreover, water present in hydrated crystals acted as a supplier of water molecules for hydrolysis of titania precursors.…”

“…88 TiO 2 has been the most extensively studied semiconductor for photocatalytic purposes due to its abundance, low cost, non-toxicity and high photoactivity accompanied by a high oxidation and reduction potential. TiO 2 can oxidize a large variety of organic compounds in water or air 182,189,193,200,203,[254][255][256][257][274][275][276][277][278] and has also been successful for reducing metal ions such as Cr 6+ 193 and for H 2 production. 254 The major factors affecting the degree of photoactivity are surface area, porosity, crystallinity and morphology.…”

Recent Progress of TiO2-Based Anodes for Li Ion Batteries

“…Structure. Recently, threedimensional (3D) porous structure materials exhibiting interesting electrochemical performance in LIBs have attracted more attention, due to their special nature including highly exposed skeleton, tunable pore size, high porosity, high specific surface area, and low bulk density [59,60]. As described, first, the unique structure is conductive to enhance the diffusion kinetics for its short diffusion paths for Li ions.…”

The Effect of Process Condition on the Structure and Optical Properties of Zn/Fe/Sn/Sb-TiO2Three Dimensional Particle-Electrode

“…Moreover, these materials can be widely applied in photoelectric devices, catalysis, drug delivery, chromatography separation and chemical reactors [7][8][9][10][11][12] . Various synthetic methods were explored to prepare hollow nanomaterials including self-assembly techniques, hydrothermal techniques, template-assisted techniques and chemically induced self-transformation [13][14][15] . Up to now, template-assisted synthetic method has been proved to be the most-applied and most-effective route to fabricate inorganic hollow structures.…”