Hydrogen trititanate (H 2Ti 3O 7) nanofibers were prepared by a hydrothermal method in 10 M NaOH at 403 K, followed by acidic rinsing and drying at 383 K. Calcining H 2Ti 3O 7 nanofibers at 573 K led to the formation of TiO 2 (B) nanofibers. Calcination at 673 K improved the crystallinity of the TiO 2 (B) nanofibers and did not cause any change in the morphology and dimensions of the nanofibers. TiO 2 (B) and H 2Ti 3O 7 nanofibers are 10-20 nm in diameter and several micrometers long, but FE-SEM reveals that several of these nanofibers tend to bind tightly to each other, forming a fiber bundle. Calcination at 773 K transformed TiO 2 (B) nanofibers into a TiO 2 (B)/anatase bicrystalline mixture with their fibrous morphology remaining intact. Upon increasing the calcination temperature to 873 K, most of the TiO 2 (B) nanofibers were converted into anatase nanofibers and small anatase particles with smoother surfaces. In the photocatalytic dehydrogenation of neat ethanol, 1% Pt/TiO 2 (B) nanofiber calcined at 673 K was the most active catalyst and generated about the same amount of H 2 as did 1% Pt/P-25. TPR indicated that the calcination of 1% Pt/TiO 2 (B) nanofiber at 573 K produced a poor Pt dispersion and poor activity. Calcination at a temperature higher than 773 K (in ambient air) resulted in an SMSI effect similar to that observed over TiO 2 in the reductive atmosphere. As suggested by XPS, such an SMSI effect decreased the surface concentration of Pt metal and created Pt (delta) sites, preventing Pt particles from functioning as a Schottky barrier and leading to a lower activity. Because of the synergetic effect between TiO 2 (B) and anatase phases, the bicrystalline mixture, produced by calcining at 773 K, was able to counter negative effects such as the reduction in surface area and the SMSI effect and maintained its photocatalytic activity.

Sodium titanate nanotubes (NaTNTs) are converted into monoclinic TiO 2 (B) nanotubes by rinsing with 0.10 M HCl followed by drying at 573 K. As calcination temperature is increased to 673 K, these TiO 2 (B) nanotubes start to transform into anatase nanoparticles producing a bi-crystalline mixture consisting of TiO 2 (B) nanotubes and anatase nanoparticles. The primary particle size of the anatase particles was estimated to be around 10 nm using Scherrer equation. After being promoted with 1% Pt, this bi-crystalline material becomes a very active photocatalyst producing 20% more H 2 gas than 1% Pt/Degussa P-25 TiO 2 in the photocatalytic dehydrogenation of neat ethanol after 2 h of UV light irradiation.

An observer-based robust adaptive fuzzy sliding mode control algorithm is proposed in this paper for the tracking control problem of a class of single-input single-output (SISO) strict-feedback nonlinear uncertain systems in the presence of uncertainties. Because all the states of the original nonlinear systems are not available for measurement, the highgain observer is applied for estimating all states in the equivalent system. Moreover, fuzzy logic systems and some adaptive laws are used to approximate unknown nonlinear functions and the unknown bounds of uncertainties. Based on the Lyapunov stability theorem, the proposed robust adaptive fuzzy sliding mode controller can achieve the asymptotic stabilization and the output tracking performance of the whole closed-loop system. Finally, an example and simulation results are illustrated to show the effectiveness of the proposed control scheme.