Ning Liu,Bin Hu,Kexin Tang,Tingyu Xia,Fei Li,Guixiang Quan,Xiaodong Zhang,Liang Tang
In the pursuit of restoring and preserving our planet's natural equilibrium, the development of photocatalytic agents with exceptional aptitude for CO 2 reduction stands as an essential undertaking, which would be greatly facilitated with the energy regeneration and environmental purification. Herein, a composite material HTiNbO 5 /UiO-66 (UTi) was amalgamated by a one-step solvothermal method. The resultant composite material exhibited remarkable improvement on the photoreduction efficiency of CO 2 reduction compared with pristine UiO-66 and HTiNbO 5 . Impressively, UTi composite with 3 wt% HTiNbO 5 (UTi-3) illustrated the highest CO 2 photoreducation activity to CO, the CO yield of UTi-3 was about 9.3 and 11.2 times higher than that of pure UiO-66 and HTiNbO 5 , respectively. The significantly improved photocatalytic performance could be ascribed to the enlargement of specific surface area, the improved visible-light absorption range and shrinkage of the energy band gap, which can increase photogenerated electron production to promote the reduction reaction of CO 2 to CO. The insights obtained from this study can guide the application of semiconductor composites in the field of CO 2 photocatalytic reduction, so as to design high efficiency photocatalysts .
Ideal laminar membrane reactors (LMR) necessitate the rational construction of 2D nanoconfined channels and regulation of microenvironment. The intrinsic structure-activity relationship of laminar membrane reactors essentially remains unclear. Herein, amorphous/crystalline HTiNbO 5-X nanosheets (NS) with abundant oxygen vacancy (V O ) are successfully prepared and stacked as 2D sub-nanoconfined membrane flow reactors with different interlayer spacings. When the interlayer spacing is decreased to 11.0 Å, the representative HTiNbO 5-X membrane exhibits impressive conversion of ≈ 100% within 26.6 s and turnover number of up to 306.42 for the esterification of benzyl alcohol at 23 °C. The combination of structural characterizations and theoretical calculations reveals that the synergistic effect of V O and sub-nanoscale confinement greatly promotes the adsorption and orbital symmetry matching of reactants, and reduces the overall energy barrier. Furthermore, the HTiNbO 5-X LMR is accessible for other alcohol derivatives, indicating the efficient and green synthesis of acetate ester flavours under mild conditions. This work demonstrates the promising potential of the metal oxide nanosheets to create inorganic laminar membrane reactors for continuous organic synthesis.
Wen Xiao,Huan Yu,Chenghao Xu,Zhongyi Pu,Xiangyu Cheng,Fang Yu,Chao Liu,Qinfang Zhang,Zhigang Zou
Developing high-efficiency photocatalysts for tetracycline hydrochloride (TCH) degradation is of great significance to ecosystems and human beings. In this work, a two-step process of exfoliation and re-stacking was performed to prepare re-stacked HTiNbO 5 nanosheets (R-HTNS) and then coupled with Ti 3 C 2 MXene to construct Ti 3 C 2 MXene/R-HTNS (MX/RTS) with a 2D/2D Schottky heterojunction. These 2D/2D heterostructures between Ti 3 C 2 MXene and R-HTNS can produce an internal electric field and provide maximum interface area for efficient charge transfer across the intimate interface. The photocatalytic performance of samples was evaluated by TCH degradation under simulated sunlight. The MX/RTS composites, with an optimal sample of 3-MX/RTS, show enhanced photocatalytic activity for TCH degradation compared with R-HTNS. The characterization results reveal that the introduction of Ti 3 C 2 MXene can significantly increase specific surface area for providing more reactive sites and broaden the light absorption region. Besides, the incident light energy is absorbed by the Ti 3 C 2 MXene component in MX/RTS composites to generate photothermal energy (heat), which facilitates the charge carrier separation and surface reaction kinetics. Thus, the enhanced TCH photodegradation activity for MX/RTS composites is due to the introduction of Ti 3 C 2 MXene, which possesses the synergistic effect of the increased specific surface area, improved light-harvesting capacity, 2D/2D Schottky heterojunction, and photothermal energy effect. Additionally, the TCH photodegradation behavior is deliberated with a detailed discussion on various coexisting ions. During TCH photodegradation, the active radical species are determined for 3-MX/RTS. According to the characterization results, the possible TCH photodegradation pathway and mechanism over 3-MX/RTS are explored. This work may offer a novel insight for constructing MXene-based heterostructured photocatalysts with high efficiency.
危险品化学品经营许可证（带存储）