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Director of Fuel Cell and Hydrogen Research
Researchers are using nanotechnology to make important breakthroughs in clean energy applications. Learn how nanocatalysts are being used in electrolysis to generate clean hydrogen and how they could help reduce the world's dependence on fossil fuels.
August 8th, 2008
Paving the way for clean hydrogen production through the use of nanocatalysts
By Kimberly McGrath, Ph.D.
Director of Fuel Cell and Hydrogen Research
With $5-a-gallon gasoline on the near-term horizon and global climate change an inevitability, it is difficult to imagine how tiny particles measuring between three and 30 nanometers hold the key for the green, mass production of a clean fuel to meet the world's growing energy needs. But a recent breakthrough in this area is helping pave the way for this evolution.
Researchers are using nano-sized catalysts to vastly improve the production of hydrogen through water electrolysis a vastly more efficient process. The goal is to make it practical and cost-effective to produce hydrogen from water and electricity for existing industrial uses and for fueling the next-generation hydrogen-fueled vehicles.
The researchers are using tiny particles of nanometals that are almost perfectly spherical in shape. The mass production of these particles is enabled through patented, gas phase condensation method. The size and shape of the nano particles are proving to be ideal in the electrolysis process since they increase the amount of reactive surface area for the catalysts used in the electrolyzers that produce the hydrogen. By increasing the surface area of the catalysts, the efficiency of the electrolysis process has been improved to 85 percent.
Another advantage is that the catalyst also allows electrolyzers to produce the same amount of hydrogen at the same efficiency, but with about 1/2 the electrolyzer size, or less, dramatically reducing capital cost. These benefits lead researchers to believe that electrolyzers designed with nano-metal catalysts can enable distributed hydrogen production at a station or a home, which in turn helps accelerate the commercialization of hydrogen vehicles. Hydrogen will play a key role as a transportation fuel in the inevitable reduction of the world's dependence on fossil fuels.
The underlying goal of the research is to provide a crucial element in a supply chain that will enable the mass production of hydrogen in a clean, efficient and cost-effective manner. Using nano-materials to attack cost and emissions issues currently associated with hydrogen production is now opening the door for a greener supply chain.
The most common practice in producing industrial quantities of hydrogen today is by steam reformation of natural gas. In this process, natural gas is converted to hydrogen. Unfortunately, a significant amount of greenhouse gas is also produced as carbon dioxide (CO2). For every pound of hydrogen produced by the steam reformation process, four pounds of greenhouse gases are released into the atmosphere. Steam reformation also produces carbon monoxide (CO) which can remain with the hydrogen. Without expensive purification processes, the CO becomes a poison for the fuel cells expected to be used in vehicles, stationary power sources and industrial devices. Additionally, hydrogen produced by steam reformation is usually generated at large chemical plants and must be shipped to the customer in large compressed cylinders or as a liquid in a cryogenic container. Shipping not only increases cost, but it also results in the release of additional greenhouse gases into the environment from the vehicles used for transportation.
Alternative hydrogen production methods are highly desired for eliminating production of these greenhouse gasses, as well as for providing nations with independent sources of transportation fuel. Water electrolysis can be used to split water molecules with electrical energy to generate hydrogen without producing greenhouse gasses. Ideally, this process could by be powered by a renewable resource such as solar, wind, geothermal, hydroelectric or nuclear energy.
With the efficiency and costs of today's electrolysis, the process satisfies a little more than 5 percent of the hydrogen market. Now, with the increased efficiency and reduced system size resulting from the use of nano-metal catalysts, water electrolysis can begin to grow market share, and do it sooner.
Two types of electrolysis have been considered for hydrogen generation, acidic and alkaline. Acidic electrolysis is ill-suited to be the standard production method as it requires prohibitively expensive platinum as the catalyst. Alkaline electrolysis is the more promising approach because it eliminates the need for expensive precious metals to serve as a catalyst, and with high surface area nano-scale particles, the catalytic reaction is more efficient. For alkaline electrolysis, a combination of nickel and iron is ideal because it is less costly and can easily be produced at the nano-scale. By using a coating of nickel and iron particles on the electrodes used in alkaline electrolyzers, the surface area available for catalytic reactions to generate hydrogen dramatically increases. The large increase in reaction surface area in turn increases the efficiency and hydrogen production rates.
Researchers have demonstrated that by using nano nickel and iron particles it is possible to exceed the U.S. Department of Energy's target with 85 percent energy efficiency by adding the nano-metal catalyst onto the active components of an electrolyzer. The result is a technology that enables an acceleration of sustainably produced hydrogen in the marketplace, especially with the addition of very high and increasingly uncertain fossil fuel costs. In addition, the scalable manufacturing process can produce nano nickel and iron in the quantities required for large-scale commercial hydrogen production via water electrolysis. Nano scale materials are playing a major role in current and future hydrogen needs.
Does this mean we can pull up to the pumps tomorrow and start filling our tanks with hydrogen? No, but making alkaline electrolysis more efficient is a crucial enabler in the long road to creating a greater hydrogen economy, one that can eventually meet the world's energy needs without sacrificing our environment. The use of nanoparticles is playing an important role.
(Kimberly McGrath, Ph.D., is the director of Fuel Cell and Hydrogen Research
at QuantumSphere, Inc. For more information about QuantumSphere, visit http://www.qsinano.com .)