New nano-research leads to sensors that detect contaminants in water

June 6, 2012
New research leads to sensors that detect contaminants in water

(Phys.org) -- Many organic contaminants in the air and in drinking water need to be detected at very low-level concentrations. Research published by the laboratory of Prashant V. Kamat, the John A. Zahm Professor of Science at the University of Notre Dame, could be beneficial in detecting those contaminants.

The Kamat laboratory uses Surface-Enhanced Raman Spectroscopy to make use of silver nanoparticles to increase the sensitivity limit of chemical detection. Researchers in this study have prepared a semiconductor-graphene-metal film that has distinct advantages: The of on the film’s graphene surface increases the local contaminant concentration adjacent to silver nanoparticles.

The researchers have investigated the use of graphene oxide films in which the semiconductor titanium dioxide (TiO2) and metal nanoparticles are deposited on opposite sides of the graphene surface. “We are currently working toward the detection of environmental contaminants at even lower levels,” Kamat says. “Careful control of metal size and loading will be the key to optimize strips for testing water quality.”

Under UV illumination, the electrons from TiO2 are captured by the graphene oxide film and shuttled across the film to reduce metal ions into metal nanoparticles. This electron-hopping process across the graphene oxide film allows the design of a side-separated semiconductor-metal nanoparticle architecture.

Graphene, a two-dimensional crystalline form of carbon, is known for its remarkable mechanical strength, very high thermal and electrical conductivity and broad variety of applications. While the conducting properties of graphene sheets deposited on various substrates are well understood, the Kamat group has demonstrated that the transport of electrons is not limited to the 2-D plane. Here, the hopping of electrons from one side of the graphene allows for the side-selective deposition of .

“Another potential application is in the area of photocatalytic generation of solar fuels," Kamat says. "For example, having semiconductor nanoparticles on one side of a graphene sheet and a metal catalyst on the other side, one can create a hybrid assembly that can selectively split water into oxygen and hydrogen.”

Explore further: Graphene-Based Nanomat Could Lead to Next-Generation Catalysts

More information: The paper, “Electron Hopping Through Single-to-Few-Layer Grapheme Oxide Films: Side-Selective Photocatalytic Deposition of Metal Nanoparticles,” was published recently in the Journal of Physical Chemistry Letters. Authors are Ian Lightcap, Sean Murphy, Timothy Schumer and Kamat. The research was supported by the Office of Basic Energy Sciences, Department of Energy.

Related Stories

Graphene-Based Nanomat Could Lead to Next-Generation Catalysts

January 19, 2010

(PhysOrg.com) -- Researchers have found a new use for graphene, the single-atom-thick sheet of carbon atoms that resembles chicken wire. Ever since graphene was first observed in 2004, its large surface area, excellent mechanical ...

Flaky graphene makes reliable chemical sensors

January 17, 2012

Scientists from the University of Illinois at Urbana-Champaign and the company Dioxide Materials have demonstrated that randomly stacked graphene flakes can make an effective chemical sensor.

Scientists produce graphene using microorganisms

March 22, 2012

The Graphene Research Group at Toyohashi University of Technology (Japan) reports on the synthesis of graphene by reducing graphene oxide using microorganisms extracted from a local river.

Graphene boosts efficiency of next-gen solar cells

April 24, 2012

(Phys.org) -- The coolest new nanomaterial of the 21st century could boost the efficiency of the next generation of solar panels, a team of Michigan Technological University materials scientists has discovered.

Recommended for you

Meet the high-performance single-molecule diode

July 29, 2015

A team of researchers from Berkeley Lab and Columbia University has passed a major milestone in molecular electronics with the creation of the world's highest-performance single-molecule diode. Working at Berkeley Lab's Molecular ...

Better together: graphene-nanotube hybrid switches

August 2, 2015

Graphene has been called a wonder material, capable of performing great and unusual material acrobatics. Boron nitride nanotubes are no slackers in the materials realm either, and can be engineered for physical and biological ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.