Formation of chelating agent driven anodized TiO(2) nanotubular membrane and its photovoltaic application.

Titania (TiO(2)) nanotubular arrays provide an exciting material for dye sensitizing solar cells (DSSC) because of their large surface area, lower recombination losses, and fast charge transport properties along the nanotubes. In this paper, design of a next generation DSSC using a TiO(2) nanotubular membrane is discussed. A single step, green process is developed to produce stable large area, free-standing TiO(2) nanotubular films (in a short time, 30-60 min) by anodizing Ti using an organic electrolyte, containing disodium salt of ethylene diaminetetraacetic acid (Na(2)[H(2)EDTA]) as complexing agent, and subsequent drying. Transparent, crack-free TiO(2) films, 20-41 microm thick containing ordered hexagonal TiO(2) nanotubes are achieved by this process. Films having a geometrical area up to 16.5 cm(2) with pore openings of 182 nm have been obtained. These films have been etched to form membranes which provide an exciting prospect for front side illuminated DSSC with good mass and photon transport properties as well as wettability. A photovoltaic efficiency of 2.7% is achieved using a front side illuminated DSSC compared to 1.77% using back side illumination.

Synthesis of TaON nanotube arrays by sonoelectrochemical anodization followed by nitridation: a novel catalyst for photoelectrochemical hydrogen generation from water.

This communication reports the synthesis of TaON nanotube arrays as efficient visible light driven photocatalysts for photoelectrochemical generation of hydrogen from water.

A green process for producing biodiesel from feather meal.

This paper describes a new and environmentally friendly process for developing biodiesel from commercial feather meal, a waste product of the poultry industry. Currently, feather meal is used as an animal feed, given its high protein content, and also as a fertilizer because of its high nitrogen content. In this work, we have extracted fat from the feather meal in boiling water (70 degrees C) and then transesterified the fat into biodiesel using KOH and methanol; 7-11% biodiesel (on a dry basis) is produced in this process. ASTM analysis of the prepared feather meal biodiesel confirmed that the biodiesel is of good quality and comparable to other biodiesels made from other common feedstocks. Given the amount of feather meal produced by the poultry industry, it is estimated that this process can create 150-200 million gallons of biodiesel in the United States and 593.2 million gallons worldwide.

The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor.

There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.

Double-wall anodic titania nanotube arrays for water photooxidation.

Vertically oriented double-wall titania nanotube (external diameters of 82 and 206 nm) arrays are synthesized by a sonoelectrochemical anodization technique in combination with a unique room-temperature ionic liquid and organic electrolyte. Compared to similar single-wall nanotubes (0.638 mA/cm(2)) and commercial nanoparticles (0.365 mA/cm(2)), these double-wall nanotube arrays show 2-4 times more photoactivity to split water under solar light illumination to generate hydrogen and oxygen. Partial doping of B and C into the TiO(2) matrix gives rise to these double-wall nanotubes which absorb visible solar light more efficiently than the intrinsic TiO(2). The structural properties of these novel structures have been studied extensively using various spectroscopic, analytical, and electrochemical techniques.

Spent coffee grounds as a versatile source of green energy.

The production of energy from renewable and waste materials is an attractive alternative to the conventional agricultural feed stocks such as corn and soybean. This paper describes an approach to extract oil from spent coffee grounds and to further transesterify the processed oil to convert it into biodiesel. This process yields 10-15% oil depending on the coffee species (Arabica or Robusta). The biodiesel derived from the coffee grounds (100% conversion of oil to biodiesel) was found to be stable for more than 1 month under ambient conditions. It is projected that 340 million gallons of biodiesel can be produced from the waste coffee grounds around the world. The coffee grounds after oil extraction are ideal materials for garden fertilizer, feedstock for ethanol, and as fuel pellets.

Functionalization of self-organized TiO2 nanotubes with Pd nanoparticles for photocatalytic decomposition of dyes under solar light illumination.

Self-organized, vertically oriented TiO2 nanotube arrays prepared by the sonoelectrochemical anodization method are functionalized with palladium (Pd) nanoparticles of approximately 10 nm size. A simple incipient wetness method is adopted to distribute the Pd nanoparticles uniformly throughout the TiO2 nanotubular surface. This functionalized material is found to be an excellent heterogeneous photocatalyst that can decompose nonbiodegradable azo dyes (e.g., methyl red and methyl orange) rapidly (150-270 min) and efficiently (100%) under ambient conditions using simulated solar light in the absence of any external oxidative radicals such as hydrogen peroxide.

Synthesis of Fe(2)O(3)/TiO(2) nanorod-nanotube arrays by filling TiO(2) nanotubes with Fe.

Synthesis of hematite (α-Fe(2)O(3)) nanostructures on a titania (TiO(2)) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO(2) nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe/TiO(2) composite is then annealed in an O(2) atmosphere to convert it to Fe(2)O(3)/TiO(2) nanorod-nanotube arrays. The length of the Fe(2)O(3) inside the TiO(2) nanotubes can be tuned from 50 to 550 nm by changing the deposition time. The composite material is characterized by scanning electron microscopy, transmission electron microscopy and diffuse reflectance ultraviolet-visible studies to confirm the formation of one-dimensional Fe(2)O(3)/TiO(2) nanorod-nanotube arrays. The present approach can be used for designing variable one-dimensional metal oxide heterostructures.

Synthesis of carbon nanotube-TiO(2) nanotubular material for reversible hydrogen storage.

A material consisting of multi-walled carbon nanotubes (MWCNTs) and larger titania (TiO(2)) nanotube arrays has been produced and found to be efficient for reversible hydrogen (H(2)) storage. The TiO(2) nanotube arrays (diameter ∼60 nm and length ∼2-3 µm) are grown on a Ti substrate, and MWCNTs a few µm in length and ∼30-60 nm in diameter are grown inside these TiO(2) nanotubes using chemical vapor deposition with cobalt as a catalyst. The resulting material has been used in H(2) storage experiments based on a volumetric method using the pressure, composition, and temperature relationship of the storage media. This material can store up to 2.5 wt% of H(2) at 77 K under 25 bar with more than 90% reversibility.

Regio- and chemoselective catalytic transfer hydrogenation of aromatic nitro and carbonyl as well as reductive cleavage of azo compounds over novel mesoporous NiMCM-41 molecular sieves.

[reaction: see text] [corrected] Regio- and chemoselective reduction of nitroarenes and carbonyl compounds and reductive cleavage of azo compounds, including bulkier molecules, was achieved by the catalytic transfer hydrogenation method (CTH) using a novel nickel-containing mesoporous silicate (NiMCM-41) molecular sieve catalyst. In addition, the catalyst was also found to behave as a truly heterogeneous catalyst as the yield was practically unaffected.