Role of Water in the Transformation of Protonated Titanate Nanoribbons to Anatase Nanoribbons

Melita Sluban,Polona Umek

doi:10.1021/acs.jpcc.9b08225

Abstract

Transformation of layered protonated titanate (H2Ti3O7) nanoribbons to anatase nanoribbons under hydrothermal conditions is a catalyzed process where topotactic transformation and dissolution–recry...

Highlights

Titanium dioxide (TiO2) has been a subject of extensive research over the last decades due to its photoactivity.[1]
We investigated the transformation of protonated titanate nanoribbons (HTiNRs), with H2Ti3O7 layered structure, to TiO2 nanoribbons aiming at: (i) determining the role of the water in the transformation, (ii) understanding the behavior of H2Ti3O7 Nanoribbons. Protonated titanate nanoribbons (HTiNRs) under hydrothermal conditions over the whole pH range, and (iii) explaining the relationship between the product morphology and the reaction environment
Most likely two processes took place: (i) topochemical transformation of titanate to anatase NRs since the morphology was retained and (ii) NH4+ ions from the reaction mixture exchanged protons at the surface of HTiNRs and caused partial dissolution of the material, which resulted in the deposition of TiO2 nanocrystals at the surface of the TiO2 NRs41,42 (Figure 4)

Summary

■ INTRODUCTION

Titanium dioxide (TiO2) has been a subject of extensive research over the last decades due to its photoactivity.[1]. SEM analyses of the products revealed that when protonated titanate did not transform to TiO2, no morphological or surface changes of NRs occurred (Figure S9a) Those NRs appeared identical to the nanoribbons in the starting material (HTiNRs). Most likely two processes took place: (i) topochemical transformation of titanate to anatase NRs since the morphology was retained and (ii) NH4+ ions from the reaction mixture exchanged protons at the surface of HTiNRs and caused partial dissolution of the material, which resulted in the deposition of TiO2 nanocrystals at the surface of the TiO2 NRs41,42 (Figure 4) In this case the amount of NH4+ ions was too low to stabilize the layered titanate structure. Organic solvents did not ensure species that could catalyze the condensation in protonated titanate and seem to serve only as a thermal medium

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES