Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Revolution in Solar Hydrogen on the Horizon

A cheap and easily scalable technique to produce hydrogen from visible light is close to being a reality.

Revolution in Solar Hydrogen on the Horizon

University Park, PA | Posted on August 15th, 2007

The prospect for the wide spread use of hydrogen as a portable energy carrier is dependent on finding a clean, renewable method of production. At Penn State University, a research group headed by professor of electrical engineering Craig Grimes in the Materials Research Institute is "only a couple of problems away" from developing an inexpensive and easily scalable technique for water photoelectrolysis - the splitting of water into hydrogen and oxygen using light energy - that could help power the proposed hydrogen economy.

Most current methods of hydrogen production split hydrogen from natural gas in a process that produces climate changing greenhouse gas while consuming a nonrenewable resource. A more environmentally friendly approach would produce hydrogen from water using the renewable energy of sunlight.

In a paper published online in Nano Letters on July 3, 2007, lead author Gopal K. Mor, along with Haripriya E. Prakasam, Oomman K. Varghese, Kathik Shankar, and Grimes, describe the fabrication of thin films made of self-aligned, vertically oriented titanium iron oxide (Ti-Fe-O) nanotube arrays that demonstrate the ability to split water under natural sunlight.

Previously, the Penn State scientists had reported the development of titania nanotube arrays with a photoconversion efficiency of 16.5% under ultraviolet light. Titanium oxide (TiO2), which is commonly used in white paints and sunscreens, has excellent charge-transfer properties and corrosion stability, making it a likely candidate for cheap and long lasting solar cells. However, as ultraviolet light contains only about 5% of the solar spectrum energy, the researchers needed to finds a means to move the materials band gap into the visible spectrum.

They speculated that by doping the TiO2 film with a form of iron called hematite, a low band gap semiconductor material, they could capture a much larger portion of the solar spectrum. The researchers created Ti-Fe metal films by sputtered titanium and iron targets on fluorine-doped tin oxide coated glass substrates. The films were anodized in an ethylene glycol solution and then crystallized by oxygen annealing for 2 hours. They studied a variety of films of differing thicknesses and varying iron content. In this paper they report a photocurrent of 2 mA/cm2, and a photoconversion rate of 1.5%, the second highest rate achieved with an iron oxide related material.

The team is now looking into optimizing the nanotube architecture to overcome the low electron-hole mobility of iron. By reducing the wall thickness of the Ti-Fe-O nanotubes to correspond to the hole diffusion length of iron which is around 4nm, the researchers hope to reach an efficiency closer to the 12.9% theoretical maximum for materials with the band gap of hematite.

"As I see it, we are a couple of problems away from having something that will revolutionize the field of hydrogen generation by use of solar energy," Grimes says.


About The Pennsylvania State University 108 Materials Research Laboratory
The Materials Research Institute supports interdisciplinary materials research at Penn State, with more than 200 faculty, 800 graduate students, and 200 post doctoral researchers engaged in ground-breaking research in advanced materials.

For more information, please click here

The Pennsylvania State University
108 Materials Research Laboratory
University Park, PA 16802
United States

Mr. Walter Mills
Associate Editor Publications

Craig Grimes
(814) 865-9142

Copyright © Newswise

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press


Imaging technique pulls plasmon data together: Rice University scientists' hyperspectral method analyzes many plasmonic nanoparticles in an instant March 16th, 2018

Plasmons triggered in nanotube quantum wells: Rice, Tokyo Metropolitan scientists create platform for unique near-infrared devices March 16th, 2018

Movable silicon 'lenses' enable neutrons to see new range of details inside objects March 15th, 2018

Jim Barnhart Joins Nanometrics as Senior Vice President of Operations March 15th, 2018


'Sweet spot' in sweet material for hydrogen storage: Study IDs 'white graphene' architecture with unprecedented hydrogen storage capacity March 12th, 2018

Converting CO2 into Usable Energy: Scientists show that single nickel atoms are an efficient, cost-effective catalyst for converting carbon dioxide into useful chemicals March 1st, 2018

Round-the-clock power from smart bowties February 5th, 2018

Silk fibers could be high-tech ‘natural metamaterials’ January 31st, 2018


A simple new approach to plastic solar cells: Osaka University researchers intelligently design new highly efficient organic solar cells based on amorphous electronic materials with potential for easy printing January 28th, 2018

Tweaking quantum dots powers-up double-pane solar windows: Engineered quantum dots could bring down the cost of solar electricity January 2nd, 2018

Record high photoconductivity for new metal-organic framework material December 15th, 2017

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

The latest news from around the world, FREE

  Premium Products
Only the news you want to read!
 Learn More
Full-service, expert consulting
 Learn More

Nanotechnology Now Featured Books


The Hunger Project