PbS quantum dots (PbS QDs) were prepared on the inside and outside surfaces of TiO(2) nanotubes by using thiolactic acid as an organic linker. The sizes of PbS QDs were controlled by employing a dip coating process to anchor the PbS QDs onto the TiO(2) nanotubes. The PbS QDs with diameters of 2-10 nm were obtained by adjusting the concentration of thiolactic acid. TiO(2) nanotubes with PbS QDs located only inside the nanotubes were prepared by first coating the tubes with the double-chain cationic surfactant DDAB. The PbS QDs supported on TiO(2) nanotubes were characterized by TEM, as well as Raman, FT-IR, and UV-vis spectroscopy.

The present status of catalyst preparation using nonthermal plasma treatment has been summarized in this paper. Improved dispersion, better low-temperature activity, enhanced stability, and better anti-carbon deposition performance can be achieved with nonthermal plasma-treated catalysts. The improvement in catalyst preparation with nonthermal plasma treatment can reduce or avoid the use of hazardous chemicals. Nonthermal plasma catalyst treatment has especially induced a new development of nonthermal plasma for catalyst reduction. The reduction using hydrogen at high temperatures or using hazardous liquid chemicals can be replaced by the developed plasma reduction process. The mechanism for nonthermal plasma treatment has been presented. An analog between the man-made gas discharge plasmas and the environment inside the zeolite pores and around catalyst surface defects is also proposed.

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PbS quantum dots (PbS QDs) were attached to TiO2 nanotubes on both the inside and outside surfaces of the nanotubes by using thiolactic acid, a bifunctional linker. The PbS QDs with diameters of 4−5 nm were controlled by adjusting the concentration of thiolactic acid. The PbS QDs can be placed only inside the nanotubes by first blocking the outer surface of the TNTs with the double-chain cationic surfactant. The photocatalytic activity and stability of PbS/TiO2 nanotubes were evaluated for the photodegradation of organic dyes. The results indicate that the functionalized TiO2 nanotubes were superior catalysts for photodegradation of cationic dyes. Additionally, the quantum dots enhance the activity and expand the usable portion of the solar spectrum.

Nitric oxide (NO) is an endogenous diatomic molecule important in regulation of numerous physiological functions. The photorelease of NO in a controlled manner can potentially be used in photodynamic therapy (PDT). We present here a method to combine S-nitrosocysteine with TiO(2) nanotube-doped PbS quantum dots (PbS QDs) as a nitric oxide-releasing vehicle to promote production of singlet oxygen. The PbS QDs with a diameter ∼3.6 nm (PbS/TNTs) were attached to the TiO(2) nanotube by using a thiolactic acid linker. S-nitrosocysteine-decorated PbS/TiO(2) nanotubes were prepared by dipping PbS/TNTs in a cysteine solution followed by nitrosylation. The results suggest that this hybrid nanomaterial is capable of photoreleasing nitric oxide and producing singlet oxygen using near-IR light.