New way to make sensors that detect toxic...( COLUMBUS Ohio -- Ohio State Universi...)

COLUMBUS, Ohio -- Ohio State University researchers have developed a new method for making extremely pure, very small metal-oxide nanoparticles.

They are using this simple, fast, and low-temperature process to make materials for gas sensors that detect toxic industrial chemicals (TICs) and biological warfare agents.

The researchers described their work in a recent issue of the journal Materials Chemistry and Physics.

Patricia Morris, associate professor of materials science and engineering at Ohio State, leads a team of researchers who develop solid materials that can detect toxic chemicals.

The challenge, she said, is to design a material that reacts quickly and reliably to a variety of chemicals, including TICs, when incorporated into a sensor.

"These are sensors that a soldier could wear on the battlefield, or a first responder could wear to an accident at a chemical plant," Morris said.

The material under study is nickel oxide, which has unusual electrical properties. Other labs are studying nickel oxide for use in batteries, fuel cells, solar cells, and even coatings that change color.

But Morris, along with Ohio State doctoral student Elvin Beach, is more interested in how nickel oxide's electrical conductance changes when toxic chemicals in the air settle on its surface. Beach applies a thin coating of the material onto microelectro-mechanical systems (made in a similar fashion to computer chips), with a goal of identifying known toxic substances.

The design works on the same general principle as another, much more familiar sensor.

"The human nose coordinates signals from hundreds of thousands of sensory neurons to identify chemicals," Beach said. "Here, we're using a combination of electrical responses to identify the signature of a toxic chemical."

The key to making the sensor work is how the nickel oxide particles are made. Beach and Morris have devised a
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