Simultaneous hydrogen and peroxide production by photocatalytic water splitting

Photocatalytic oxidation of water is a promising method to realize large-scale H2O2 production without a hazardous and energy-intensive process. In this study, we introduce a Pt/TiO2(anatase) photocatalyst to construct a simple and environmentally friendly system to achieve simultaneous H2 and H2O2 production. Both H2 and H2O2 are high-value chemicals, and their separation is automatic. Even without the assistance of a sacrificial agent, the system can reach an efficiency of 7410 and 5096 μmol g^-1 h^–1 (first 1 h) for H2 and H2O2, respectively, which is much higher than that of a commercial Pt/TiO2(anatase) system that has a similar morphology. This exceptional activity is attributed to the more favorable two-electron oxidation of water to H2O2, compared with the four-electron oxidation of water to O2.

Hierarchical TiO2 photocatalysts with a one-dimensional heterojunction for improved photocatalytic activities

Hierarchical TiO2 photocatalysts with a one-dimensional heterojunction were synthesized via a facile template-free hydrothermal method. The TiO2 photo- catalysts were flower-like microspheres with a 3 μm diameter. The base structure of the flower-like microspheres was a uniform nanowire with a 10 nm diameter. Anatase films were evenly coated onto the surface of the rutile TiO2 nanowires to form a one-dimensional core--shell base structure. This kind of one-dimensional heterojunction is conducive to the separation of charge carriers. In addition, the hierarchical TiO2 microspheres possessed a good mesoporous structure with a high specific surface area of 260 m2/g. Thus, the light scattering and utilization efficiency were improved in this structure. The photocatalysts exhibited better performance in both photocatalytic oxidation and reduction reactions. Moreover, the novel TiO2 photocatalysts displayed excellent stability in these reactions. This kind of hierarchical TiO2 structure has never been reported in the literature. The hierarchical structure and one-dimensional heterojunction were vital to the increase in quantum efficiency. Therefore, these hierarchical TiO2 photocatalysts have potential applications in the environmental and energy fields, such as in photocatalytic degradation, hydrogen production, Li-ion batteries, and dye-sensitized solar cells.

Synergetic catalysis enhancement between H2O2 and TiO2 with single-electron-trapped oxygen vacancy

The TiO2-H2O2 system possesses excellent oxidation activity even under dark conditions.However,the mechanism of this process is unclear and inconsistent.In this work,the binary component system containing TiO2 nanoparticles(NPs)with single electron-trapped oxygen vacancy(SETOV,Vo-)and H2O2 exhibit excellent oxidative performance for tetracycline,RhB,and MO even without light irradiation.We systematically investigated the mechanism for the high activity of the TiO2-H2O2 under dark condition Reactive oxygen species(ROS)induced from H2O2 play a significant role in improving the catalytic degradation activities.X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)results firstly confirm that H2O2 is primarily activated by SETOVs derived from the TiO2 NPs through direct contribution of electrons,producing both.O2^-/·OOH and.OH,which are responsible for the excellent reactivity of TiO2-H2O2 system.This work not only provides a new perspective on the role of SETOVs playing in the H202 activation process,but also expands the application of TiOz in environmental conservation.

Progress in the synthesis and applications of hierarchical flower-like TiO_2 nanostructures

Flower-like TiO2 materials, with their advantages of high specific surface area, developed pore structure, and high photocatalytic activity, have been widely used in environmental management and air purification, sterilization, and surface self-cleaning, among other areas. This paper summarizes several methods used to fabricate the flower-like TiO2 nanostructures, such as the hydrothermal, solvothermal, microemulsion, sol-gel, hydrolysis, and electrodeposition oxidation methods. In addition, the morphologies, properties, and performance of different flower-like TiO2 structures are discussed. Meanwhile, the application progresses of different flower-like TiO2 structures are also analyzed.