Cheap hybrid outperforms rare metal as fuel-cell catalyst

Cheap hybrid outperforms rare metal as fuel-cell catalyst
Rice University scientists combined graphene quantum dots, graphene oxide, nitrogen and boron into a catalyst capable of replacing platinum in fuel cells at a fraction of the cost. Illustration courtesy of the Tour Group

(Phys.org) —Graphene quantum dots created at Rice University grab onto graphene platelets like barnacles attach themselves to the hull of a boat. But these dots enhance the properties of the mothership, making them better than platinum catalysts for certain reactions within fuel cells.

The Rice lab of chemist James Tour created dots known as GQDs from coal last year and have now combined these nanoscale dots with microscopic sheets of graphene, the one-atom-thick form of carbon, to create a hybrid that could greatly cut the cost of generating energy with fuel cells.

The research is the subject of a new paper in the American Chemical Society journal ACS Nano.

The lab discovered boiling down a solution of GQDs and graphene oxide sheets (exfoliated from common graphite) combined them into self-assembling nanoscale platelets that could then be treated with nitrogen and boron. The hybrid material combined the advantages of each component: an abundance of edges where take place and excellent conductivity between GQDs provided by the graphene base. The boron and nitrogen collectively add more catalytically active sites to the material than either element would add alone.

"The GQDs add to the system an enormous amount of edge, which permits the chemistry of oxygen reduction, one of the two needed reactions for operation in a ," Tour said. "The provides the conductive matrix required. So it's a superb hybridization."

Cheap hybrid outperforms rare metal as fuel-cell catalyst
An electron microscope image shows flake-like nanoplatelets made of graphene quantum dots drawn from coal and graphene oxide sheets, modified with boron and nitrogen. The nanoplatelets feature enough edge to make them suitable as catalysts for applications like fuel cells. Courtesy of the Tour Group

The Tour lab's material outperformed commercial platinum/carbon hybrids commonly found in fuel cells. The material showed an of about 15 millivolts more in positive onset potential – the start of the reaction – and 70 percent larger current density than platinum-based catalysts.

The materials required to make the flake-like hybrids are much cheaper, too, Tour said. "The efficiency is better than platinum in terms of oxygen reduction, permitting one to sidestep the most prohibitive hurdle in fuel-cell generation—the cost of the precious metal," he said.

Cheap hybrid outperforms rare metal as fuel-cell catalyst

Explore further

Coal yields plenty of graphene quantum dots

More information: "Boron- and Nitrogen-Doped Graphene Quantum Dots/Graphene Hybrid Nanoplatelets as Efficient Electrocatalysts for Oxygen Reduction." Huilong Fei, et al. ACS Nano, Just Accepted Manuscript, September 24, 2014. DOI: 10.1021/nn504637y
Journal information: ACS Nano

Provided by Rice University
Citation: Cheap hybrid outperforms rare metal as fuel-cell catalyst (2014, October 1) retrieved 18 August 2019 from https://phys.org/news/2014-10-cheap-hybrid-outperforms-rare-metal.html
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Oct 01, 2014
Is it better than Graphene iodide? Graphene Iodide catalysts can handle more cycles, run at better efficiency, and don't poison in the same way that Platinum catalysts do.

Oct 01, 2014
The solar-haters are having a hard time, since we get at least on advancement a week with PV technologies. We can always use our coal to provide the graphite for our alternative energy processes.

Oct 01, 2014
Who makes Quantum Dots??? Quantum Materials Corp There site is www.qmcdots.com If you invest this is the only publically traded company with the capability, technology and the means to economically mass produce Tetrapod Quantum Dots . There ticker is QTMM

Oct 02, 2014
Mr. Kuehl,

Put a house load on it and see if you still get what you think you will out of it. The generator heads you advocate require a 15-HP motor just to run them. Try powering one of those with a tractor battery at the same time as you power your house off the grid. You cannot get something for nothing in the real world, unfortunately.

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