Jun Dai,Juan Yang,Xiaohan Wang,Lei Zhang,Yingjie Li
Wirelike catalysts of mixed-phase TiO 2 (B)/anatase TiO 2 , bare anatase TiO 2 and TiO 2 (B) are synthesized via calcining precursor hydrogen titanate obtained from hydrothermal process at different temperatures between 450 and 700 °C. Under visible light irradiation, mixed-phase TiO 2 (B)/anatase TiO 2 catalysts exhibit enhanced photocatalytic activity in comparison with pure TiO 2 (B) and anatase TiO 2 toward selective oxidation of benzylamines into imines and the highest photocatalytic activity is achieved by TW-550 sample consisting of 65% TiO 2 (B) and 35% anatase. The difference in photocatalytic activities of TiO 2 samples can be attributed to the different adsorption abilities resulted from their crystal structures and interfacial charge separation driven by surface-phase junctions between TiO 2 (B) and anatase TiO 2 . Moreover, the photoinduced charge transfer mechanism of surface complex is also proposed over mixed-phase TiO 2 (B)/anatase TiO 2 catalysts. Advantages of this photocatalytic system include efficient utilization of solar light, general suitability to amines, reusability and facile separation of nanowires catalysts.
Water pollution caused by antibiotics is a growing problem. Semiconductor photocatalysis is an environmentally friendly technology that can effectively degrade organic pollutants in water. Therefore, the development of efficient photocatalysts is of great significance to solve the environmental pollution problem. In this paper, mixed-phase TiO2 and 1T/2H-MoS2 composite (1T/2H-MoS2/TiO2) were synthesized by the in situ growth method. The prepared compounds were characterized and applied to the visible-light degradation of tetracycline hydrochloride. The photocatalytic effect of 1T/2H-MoS2/TiO2 on tetracycline hydrochloride is significantly enhanced under visible light and has good stability. It has potential applications in the treatment of organic pollutants in water.
A series of composites consisting of anatase-rutile TiO2 and graphene (TrG) were synthesized by a hydrothermal route. The influence of the amount of graphene oxide on the photocatalytic activity during the degradation of methyl blue was studied. The photocatalysts were characterized
by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET)
specific surface area measurements. The results show that as-prepared TiO2 formed in the anatase and rutile phase with a bar structure and it dispersed uniformly over the surface of the graphene sheets. The composites possess higher catalytic activity because of the strong absorption
capacity of graphene, the establishment of heterojunctions between rutile and anatase TiO2, the remarkable electrical transport between TiO2 and graphene and the high specific surface areas. The photodegradation performance of methyl blue by the TrG composites under UV
light was studied. Our results indicate that the photocatalytic activities of titanium dioxide-graphene composites were higher than those of pure TiO2. We also found that the TrG composites prepared with a loading of 0.8%(mass fraction, w) graphene oxide had the best photocatalytic
activity.
Li–CO 2 battery provides a new strategy to simultaneously solve the problems of energy storage and greenhouse effect. However, the severe polarization of CO 2 reduction and CO 2 evolution reaction impede the practical application. Herein, anodic TiO 2 nanotube arrays are first introduced as carbon-free and free-standing cathode for photo-assisted Li–CO 2 battery, and the photo-assisted charge and discharge mechanism is first clarified from the perspective of photocatalysis. Mixed-phase TiO 2 exhibits a long cycling life of 580 h (52 cycles) at 0.025 mA cm −2 and delivers a high discharge specific capacity of 3001 µAh cm −2 under UV illumination. The charge voltage dramatically reduces from 4.53 to 3.03 V under UV illumination. The improvement of photo-assisted Li–CO 2 battery performance relies on the synergistic effect of the hierarchical porous structure, strong UV absorption, efficient separation, and transfer of photo-generated electrons and holes at hetero-phase junction, and the facilitation of photo-generated electrons and holes on CO 2 reduction and CO 2 evolution reaction. This work can provide useful guidance for designing efficient photocathode for photo-assisted Li–CO 2 battery and other metal–air batteries.
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