Surface Mineralization of Cellulose by Metal Chloride – an Original Pathway for the Synthesis of Hierarchical Urchin and Needle Carpetlike TiO₂ Superstructures

Abstract

A new pathway has been developed for the preparation of hierarchical TiO2 structures obtained “with‐and‐from” the surface of cotton. By reaction with TiCl4 under anhydrous conditions, mineralization of the outer part of the cotton fiber produces hierarchical TiO2 superstructures: at the nanoscale, anatase needles are made of nanorod assemblies and these needles are assembled into urchins and carpets at the submicrometer scale. This one‐step cotton fiber cellulose mineralization process differs from a simple deposition from inorganic sol; here, cellulose acts as both a reacting oxygen donor and also as a biotemplate. The material has high‐temperature crystal stability, and its photocatalytic activity in the UV range, without any doping, is higher than that of titania standard P25. The high photoactivity is ascribed to efficient light harvesting by hierarchical superstructures, efficient charge separation with reduced recombination in the crystalline material, and efficient sorption ability. From a general standpoint, our findings could be adapted to other metal oxides and pave the way to a number of solar‐cell, energy‐storage, and photonic‐sensor applications.

Synthesis of Titania@Carbon Nanocomposite from Urea‐Impregnated Cellulose for Efficient Lithium and Sodium Batteries

“…The preferred cellulose source used in our research was filter paper (FP) with a minimum content of 98 % of α‐cellulose, but the present methodology can be extended easily to other cellulose sources . Typical SEM images of the smooth fibers from cellulose FP with diameter of approximately 20 μm are shown in Figure a–c.…”

“…The mineralization of u FP was performed by the solvothermal reaction of titanium tetrachloride and u FP in dichloromethane at 80 °C for 7 days. Mineralization can produce TiO 2 by different possible reaction pathways: (i) Ti−Cl alcoholysis, (ii) Ti−Cl/C−O exchange, (iii) hydrolysis with the water of crystallization of TiCl 4 , and (iv) possible intra‐ or inter‐dehydration of cellulose . The shape and mechanical consistency of the TiO 2 @ u FP hybrid material, after solvothermal treatment, is similar to that of the starting u FP.…”

The Reductive Dehydration of Cellulose by Solid/Gas Reaction with TiCl4 at Low Temperature: A Cheap, Simple, and Green Process for Preparing Anatase Nanoplates and TiO2/C Composites

“…Interestingly, if calcination is performed at 650 °C, rutile is present along with the same morphology, however the photocatalytic performance is now lower than the one of TiO 2 –600. These promising results could due to the specific morphology and/or surface chemistry of the prepared samples as previously evidenced in other cases of nanostructured TiO 2 . Additional experiments are however required to validate this explanation.…”

Hybrid metal oxide@biopolymer materials precursors of metal oxides and metal oxide-carbon composites

“…140) Besides its simplicity, the most interesting in this approach is certainly the unique and special morphology of the metal oxide nanoparticles, different from the rounded shape always reported. Nanorods assembled in needles 141) or lacework formations, 142) forming super structure like flowers, urchins or carpets are example of what can be done in the case of TiO 2 , as illustrated in Fig. 10.…”