Enhancement of photocatalytic activity for electrospun C@Ti/anatase fibers by lattice distortion under anisotropic stress

Abstract

A C@Ti/anatase nanoporous fiber, where C ions replace the positions of Ti (1-5%) in the lattice, was prepared quasi-in situ by electrospinning a titanate gel containing a polyethylene-polypropylene glycol additive. Compared with immobilized nano-TiO2 and anatase fibers, C@Ti/anatase fibers showed improved optical absorption for visible light. The improved photocatalytic activity of the fibers was further testified by its decomposition of 2,4,6-trichlorophenol (TCP) and methyl orange (MO) under visible light irradiation. The strengthened optical absorptivity was attributed to modifying the energy band structure in the lattice of anatase which results from isotropic and anisotropic stress. Based on analysis by first principle theory calculations, the C@Ti/anatase has been evidenced to be "softer" than the pure anatase ones, and easily affected by micro-residual stress. The lattice parameters of the C@Ti/anatase fibers became distorted when anisotropic compressive stresses were applied, resulting in a narrowed band gap.

Ionic Polymer Microspheres Bearing a CoIII–Salen Moiety as a Bifunctional Heterogeneous Catalyst for the Efficient Cycloaddition of CO2 and Epoxides

“…[11][12][13] Difficulti solation procedures for these catalysts necessitatest he development of highlye fficient heterogeneous catalysts for the synthesis of cyclic carbonates. [14,15] Severalt ypeso fh eterogeneous catalyst, includingm etal oxides, [16] supported salen-metal complexes, [17,18] metal-organic frameworks (MOFs), [19][20][21] supported ILs, [22][23][24] and porous ionic polymers [25,26] have been explored to catalyze the cycloaddition of epoxides with CO 2 .H owever,i n most of these cases, additivesand/orco-catalysts, as well as organic solvents, are often needed.…”

TiO2–Based Nanofibrous Membranes for Environmental Protection

“…In order to improve the efficiency of anatase titanium dioxide in the photodegradation process, doping with copper (II) sulfide and carbon can be performed [42,86,87]. Dai and Yin studied the carbon doping effect on anatase titanium dioxide in photocatalytic applications.…”

“…Dai and Yin studied the carbon doping effect on anatase titanium dioxide in photocatalytic applications. They reported that the electron structure of anatase was not affected directly by carbon doping, but, under a slight stress, it denatured the "softened" anatase crystal's lattice and induced the narrowing of the band gap, thus improving its optical capacity [86].…”

Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

“…There is a clear need for the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. In recent years, heterogeneous photocatalysis technique by semiconductors has attracted a lot of attention in the water purification of dissolved-organic-compound contained water without generating harmful by-products (Dai and Yin 2014;Han et al 2014;Yin et al 2010;Zhang et al 2012;Xia et al 2014). Among the available, semiconductive TiO 2 nanoparticles has proven to be the most promising (Graetzel 2001), with reported advantages of low cost and toxicity, greatly enhanced surface area, tunable properties which can be modified by size reduction, doping, or sensitizer, no substantial loss of photocatalytic activity after repeated process cycles, enhanced photo-induced charge transport (Hagfeldtt et al 1992) and no depletion layer formation on the surface (Nazeruddin et al 1993).…”