Permethylated cyclooligosiloxane rings, tetraethylortosilicate (TEOS), and Ti(iPr) 2 Cl 2 were used to prepare hybrid TiO 2 -SiO 2 xerogels. A number of solvents were ineffective for leaching the organic silicon from the samples at 336 K after several hours. The nitrogen desorption isotherms of these materials reveal that microporous structures with broad pore size distributions are generated upon gelation. Characterization of the samples by means of 29 Si CP/MAS NMR shows incorporation of the "organic silicon" into the amorphous structure and also suggests a great extent of homogeneity in the proton distribution around all tetrahedral silicate centers. The thermal stability of these hybrid TiO 2 -SiO 2 materials was studied under flowing nitrogen and air by means of temperature-programmed (TP) techniques, and in situ diffuse reflectance infrared spectroscopy (DRIFTS). The stability of the Si-C bond in the absence of oxygen is hardly influenced by the presence of Ti. All Ticontaining samples undergo high-temperature pyrolytic decomposition of the Si-C bond, even when oxygen was present. In the presence of oxygen, the Ti function catalyzes the complete oxidation of the remaining alkoxide groups, rather than Si-C bond oxidation. The thermal stability of the latter and the decomposition of alkoxide groups into olefins are confirmed by both TP methods and DRIFTS.

No abstract

Titanium dioxide (TiO 2 ), which is regarded as a semiconductor photocatalyst, has drawn attention in the applications of photocatalysis, including hydrogen evolution reaction, carbon dioxide reduction, pollutant degradation, and biocatalytic or dye-sensitized solar cells due to its low toxicity, superior photocatalytic activity, and good chemical stability. However, there are still some disadvantages such as too large energy bandgap (~3.34 eV and ~3.01 eV for anatase and rutile phases, respectively) in the absorbance of all ranges of lights, which limits the photoelectrochemical performance of TiO 2 . Herein, we like to introduce photocatalytic blue TiO 2 that is obtained by the reduction of TiO 2 . The blue TiO 2 consists of Ti 3+ state with high oxygen defect density that can absorb the visible and infrared as well as ultraviolet light due to its low energy bandgap, leading to enhance a photocatalytic activity. This chapter covers the structure and properties of blue TiO 2 , its possible applications in visible-light-driven photocatalysis, and mainly various synthetic methods even including phase-selective room-temperature solution process under atmospheric pressure.

Both the prediction and design of protein structure, using computational and rational approaches, remain significant challenges in protein chemistry. A major limitation to developing a comprehensive physicochemical model of the protein structure‐sequence relationship is the vastness of sequence space and the low‐throughput nature of biophysical studies. We are pursuing a combinatorial approach to understand better the sequence structure‐relationship: sorting large libraries of protein variants for structured proteins. We have developed a high‐throughput cell‐based screen for activity of the well‐studied four‐helix bundle protein Rop. To collect quantitative stability data for large numbers of variants, we have developed a method of high‐throughput hydrophobic dye binding called High‐Throughput Thermal Scanning (HTTS) which can be applied using automation and a real‐time PCR machine 96‐wells at a time. This system is being used to directly test the “rules” of protein design, taking those rules as hypotheses and sorting the resulting libraries for structure and stability. Here we will discuss the in‐depth analysis of a library of hydrophobic core variants, as well as initial results from surface libraries and rational design based on library statistics. This work was supported by a grant from the NIH (R01 GM083114) to TJM.

No abstract