Oct
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A New Catalyst Made From Coal Out Performs Platinum
October 2, 2014 | 1 Comment
In a fuel cell application the graphene quantum dots grab onto graphene platelets like barnacles attach themselves to the hull of a boat. The graphene quantum dots enhance the properties of the graphene platelets making them better than platinum catalysts for certain reactions within fuel cells.
Graphene Quantum Dots to Replace Platinum. Image Credit: The Tour Group/Rice University)
The Rice lab of chemist James Tour created dots known as GQDs from coal last year and has 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. As well as operating the research lab, Professor Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of materials science and nanoengineering and of computer science.
Tour’s team 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 chemical reactions 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.
Tour explained, “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 fuel cell. The graphene provides the conductive matrix required. So it’s a superb hybridization.”
The Tour lab’s material outperformed commercial platinum/carbon hybrids commonly found in fuel cells. The material showed an oxygen reduction reaction of about 15 millivolts more in positive onset potential – the start of the reaction – and 70 percent larger current density than platinum-based catalysts.
Tour said the materials required to make the flake-like hybrids are much cheaper, too, “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.”
Rice graduate student Huilong Fei is the paper’s lead author. Co-authors are graduate students Ruquan Ye, Gonglan Ye, Yongji Gong, Zhiwei Peng and Errol Samuel; research technician Xiujun Fan; and Pulickel Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry and chair of the Department of Materials Science and NanoEngineering, all of Rice.
Perhaps this is the next step to fuel cell ascendance in the hydrogen fuel market. While the scalability isn’t a part of the news, graphene is getting more industrial attention. Costs will be coming down as the usefulness of graphene finds its way into more products.
This is valuable research sure to interest commercial concerns and stimulate more research. Please note the Rice press release page has many more photos for viewing.
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You know that would really yank the Environmentalists’ chain if their non-polluting fuel cell was made with coal!