Caixian Zhao

A novel composite of TiO2 nanotubes with remarkably high efficiency for hydrogen production in solar-driven water splitting

As one of the most promising photocatalysts, TiO2 suffers from disadvantages of a wide band gap energy and especially the ultrafast recombination of photoinduced-charges, which limit its practical application for efficient solar water splitting. Here we show a hitherto unreported carbon/TiO2/carbon nanotube (CTCNT) composite featuring a TiO2 nanotube sandwiched between two thin tubes of carbon with graphitic characteristics. The carbon layer is only about 1 nm thick covering the surface of TiO2 nanotubes. The minimum bandgap between the edges of band tails for the CTCNTs can conjecturally be narrowed to 0.88 eV, and the measured apparent quantum efficiency of CTCNT in the ultraviolet light region is even close to 100%, indicating it can greatly enhance the utilization of sunlight and extremely suppress charge recombination. As a consequence, under illumination of one AM 1.5G sunlight, CTCNT can give a super-high solar-driven hydrogen production rate (37.6 mmol h−1 g−1), which is much greater than the best yields ever reported for TiO2-based photocatalysts. We anticipate this work may open up new insights into the architectural design of nanostructured photocatalysts for effective capture and conversion of sunlight.

Studies on the Properties of a New Hybrid Materials Containing Hyperbranched Polymer and SiO2‐TiO2 Networks

EP/SiO2‐TiO2 hybrid materials, which contained hyperbranched polymers (HBPs) chain‐extended urea, were prepared through a sol‐gel process of triethoxylsilyl functionalized HBPs, i.e., chain‐extended urea—H20‐Si(OC2H5), Tetraethoxysilane (TEOS) and tetrabutyltitanate (TBT) using HCl as catalyst. The H20‐Si(OC2H5)3 was obtained by endcapped H20 with tolylene 2,4‐diisocyanate (TDI), followed by a reaction with 3‐aminopropyltriethoxylsilane (WD‐50). The chemical structure of the products was confirmed by IR spectroscopy. The mechanical properties of composites such as, impact strength, tensile strength, dynamic mechanical thermal properties were investigated. The results showed that the glass transition temperatures and the modulus of the modified systems were higher than that of the unmodified system, and the impact strength was enhanced by two times or that compared with the neat epoxy. The morphological structure of the impact fracture surface and the surface of the hybrid were observed by scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively.