Ningning Liu,Lanlan Yu,Baojun Liu,Fei Yu,Liqing Li,Yi Xiao,Jinhu Yang,Jie Ma
Constructing faradaic electrode with superior desalination performance is important for expanding the applications of capacitive deionization (CDI). Herein, a simple one-step alkalized treatment for in situ synthesis of 1D TiO 2 nanowires on the surface of 2D Ti 3 C 2 nanosheets, forming a Ti 3 C 2 -MXene partially derived hierarchical 1D/2D TiO 2 /Ti 3 C 2 heterostructure as the cathode electrode is reported. Cross-linked TiO 2 nanowires on the surface help avoid layer stacking while acting as the protective layer against contact of internal Ti 3 C 2 with dissolved oxygen in water. The inner Ti 3 C 2 MXene nanosheets cross over the TiO 2 nanowires can provide abundant active adsorption sites and short ion/electron diffusion pathways. . Density functional theory calculations demonstrated that Ti 3 C 2 can consecutively inject electrons into TiO 2 , indicating the high electrochemical activity of the TiO 2 /Ti 3 C 2 . Benefiting from the 1D/2D hierarchical structure and synergistic effect of TiO 2 and Ti 3 C 2 , TiO 2 /Ti 3 C 2 heterostructure presents a favorable hybrid CDI performance, with a superior desalination capacity (75.62 mg g −1 ), fast salt adsorption rate (1.3 mg g −1 min −1 ), and satisfactory cycling stability, which is better than that of most published MXene-based electrodes. This study provides a feasible partial derivative strategy for construction of a hierarchical 1D/2D heterostructure to overcome the restrictions of 2D MXene nanosheets in CDI.
Malachite green (MG)-contaminated aquatic products pose a serious threat to animal and human health. Hence, a novel recyclable surface-enhanced Raman scattering (SERS) substrate based on AuNPs/TiO 2 /Ti 3 C 2 heterostructures was developed for the detection and degradation of MG in aquatic products. Specifically, AuNPs/TiO 2 /Ti 3 C 2 heterostructures were synthesized by in situ oxidation and electrostatic adsorption based on Ti 3 C 2 nanosheets. The excellent photocatalytic and SERS performance of the AuNPs/TiO 2 /Ti 3 C 2 was demonstrated by Density functional theory (DFT) calculations and experimental results, which was attributed to the enhancement of charge transfer (CT) after the formation of heterostructures. The results demonstrate that AuNPs/TiO 2 /Ti 3 C 2 is highly sensitive and recyclable. The detection limit of the sensor for MG is 8.91 × 10 −5 mg/L. The sensor can be recycled for five times under the condition of light, and shows satisfactory self-cleaning performance in the food matrix, providing a possible alternative solution for the recyclable detection of MG.
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