Hydrothermal etching fabrication of TiO2@graphene hollow structures: mutually independent exposed {001} and {101} facets nanocrystals and its synergistic photocaltalytic effects

Abstract

Highly exposed facets TiO2 attracts enormous attention due to its excellent separation effect of photogenerated electron-hole pairs and induced high performance of photocatalytic activity. Herein, a novel hydrothermal etching reaction was used to synthesize graphene-wrapped TiO2 hollow core-shell structures. Different with the reported co-exposed facets TiO2 single crystal nanoparticles, the present TiO2 core layer is composed by the mutually independent exposed {001} and {101} facets nanocrystals. Combined with the reduced graphene oxide shell layer, this graphene-wrapped TiO2 hollow core-shell structures formed a Z-scheme photocatalytic system, which possess simultaneously the high charge-separation efficiency and strong redox ability. Additionally, the as-prepared samples show a higher absorption property for organic molecules and visible light due to the presence of graphene. All of these unique properties ensure the excellent photocatalytic activity for the graphene-wrapped TiO2 hollow structures in the synergistic photo-oxidation of organic molecules and photo-reduced of Cr(VI) process. The TiO2 core composed with mutually independent exposed {001} and {101} facets nanocrystals is propose to play an important role in the fabrication of this Z-scheme photocatalytic system. Fabrication of Z-scheme photocatalytic system based on this unique exposed facets TiO2 nanocrystals will provides a new insight into the design and fabrication of advanced photocatalytic materials.

Cr(VI) remediation from aqueous environment through modified-TiO2-mediated photocatalytic reduction

“…Graphene-wrapped differently faceted (001 and 101) TiO 2 hollow-core–shell microspheres (TGHMs) have been fabricated by Liu et al and were applied for efficient photocatalytic Cr(VI) reduction [134]. They prepared the photocatalyst using a direct-wrapped route followed by hydrothermal etching.…”

“…Reprinted from [134], an article distributed under the Creative Commons Attribution 4.0 license, http://creativecommons.org/licenses/by/4.0/, copyright the authors of [134]. …”

“…Even after five cycles, there was no decrease of the performance of the catalyst, showing its high photostability [134]. RGO–Mn–TiO 2 exhibited excellent stability with the high Cr(VI) removal efficiency of 96.61%, even after three cycles [137].…”

Photocatalytic treatment of tetracycline antibiotic wastewater by silver/TiO2 nanosheets/reduced graphene oxide and artificial neural network modeling

“…The ratio of I D / I G was also calculated for the purchased GO and as‐obtained samples (Table ). The I D / I G ratio for GO is smaller than the synthesized samples, verifying successfully deoxygenation and reduction of GO to rGO during hydrothermal reaction (Chen, Zhou, Zhang, Tang, & Wang, ; Liu et al, ; Zhou et al, ).…”

“…Also, the above‐mentioned blue‐shift is due to the strong chemical interaction between TNs and rGO sheets, which is needed for efficient electron transfer kinetics. In the Raman spectra of TG and TGA( x ) samples, two additional bands were observed at 1,343.5 cm −1 (D band) and 1594.9–1600 cm −1 (G band), confirming that the graphene component remained unchanged during the hydrothermal synthesis (Figure b) (Liu, Liu, Zhang, Dong, & Liu, ; Wang, Wang, Qu, Lu, & Xu, ; Yu, Ma, & Liu, ; Zhou et al, ). The ratio of I D / I G was also calculated for the purchased GO and as‐obtained samples (Table ).…”