More Durable Fuel Cells For Hydrogen Electric Car

Take a ride on the University of Delaware’s (UDFuel Cell bus, and you see that fuel cells can power vehicles in an eco-friendly way. In just the last two years, Toyota, BMW and Honda have released vehicles that run on fuel cells, and carmakers such as GM, BMW and VW are working on prototypes.  If their power sources lasted longer and cost less, fuel cell vehicles could go mainstream faster. Now, a team of engineers at UD has developed a technology that could make fuel cells cheaper and more durable.

Hydrogen-powered fuel cells are a green alternative to internal combustion engines because they produce power through electrochemical reactions, leaving no pollution behind. Materials called catalysts spur these electrochemical reactions. Platinum is the most common catalyst in the type of fuel cells used in vehicles. However, platinum is expensive — as anyone who’s shopped for jewelry knows. The metal costs around $30,000 per kilogram. Instead, the UD team made a catalyst of tungsten carbide, which goes for around $150 per kilogram. They produced tungsten carbide nanoparticles in a novel way, much smaller and more scalable than previous methods.

The material is typically made at very high temperatures, about 1,500 Celsius, and at these temperatures, it grows big and has little surface area for chemistry to take place on,” explains Vlachos, professor at the Catalysis Center for Energy Innovation (UD). “Our approach is one of the first to make nanoscale material of high surface area that can be commercially relevant for catalysis.”

The researchers made tungsten carbide nanoparticles using a series of steps including hydrothermal treatment, separation, reduction, carburization and more. The results are described in a paper published in Nature Communications.


How To Convert Heat Into Electricity

The same researchers who pioneered the use of a quantum mechanical effect to convert heat into electricity have figured out how to make their technique work in a form more suitable to industry. In Nature Communications, engineers from The Ohio State University (OSU) describe how they used magnetism on a composite of nickel and platinum to amplify the voltage output 10 times or more—not in a thin film, as they had done previously, but in a thicker piece of material that more closely resembles components for future electronic devices.

Many electrical and mechanical devices, such as car engines, produce heat as a byproduct of their normal operation. It’s called “waste heat,” and its existence is required by the fundamental laws of thermodynamics, explained study co-author Stephen Boona.

devices-that-convert-heat-into-electricityOver half of the energy we use is wasted and enters the atmosphere as heat,” said Boona, a postdoctoral researcher at Ohio State. “Solid-state thermoelectrics can help us recover some of that energy. These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also too expensive and not quite efficient enough to warrant widespread use. We’re working to change that.”But a growing area of research called solid-state thermoelectrics aims to capture that waste heat inside specially designed materials to generate power and increase overall energy efficiency.


Cost-effective Hydrogen Production From Water

Groundbreaking research at Griffith University (Australia) is leading the way in clean energy, with the use of carbon as a way to deliver energy using hydrogen. Professor Xiangdong Yao and his team from Griffith’s Queensland Micro- and Nanotechnology Centre have successfully managed to use the element to produce hydrogen from water as a replacement for the much more costly platinum.

Tucson fuel cellTucson fom Hyundai: A Hydrogen Fuel Cell Car

Hydrogen production through an electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells,” says Professor Yao. “Despite tremendous efforts, exploring cheap, efficient and durable electrocatalysts for hydrogen evolution still remains a great challenge. “Platinum is the most active and stable electrocatalyst for this purpose, however its low abundance and consequent high cost severely limits its large-scale commercial applications. “We have now developed this carbon-based catalyst, which only contains a very small amount of nickel and can completely replace the platinum for efficient and cost-effective hydrogen production from water.

In our research, we synthesize a nickel–carbon-based catalyst, from carbonization of metal-organic frameworks, to replace currently best-known platinum-based materials for electrocatalytic hydrogen evolution“, he adds. “This nickel-carbon-based catalyst can be activated to obtain isolated nickel atoms on the graphitic carbon support when applying electrochemical potential, exhibiting highly efficient hydrogen evolution performance and impressive durability.”

Proponents of a hydrogen economy advocate hydrogen as a potential fuel for motive power including cars and boats and on-board auxiliary power, stationary power generation (e.g., for the energy needs of buildings), and as an energy storage medium (e.g., for interconversion from excess electric power generated off-peak).


Fuel Cell Electrodes 7 Times More Efficient

A new fabrication technique that produces platinum hollow nanocages with ultra-thin walls could dramatically reduce the amount of the costly metal needed to provide catalytic activity in such applications as fuel cells. The technique uses a solution-based method for producing atomic-scale layers of platinum to create hollow, porous structures that can generate catalytic activity both inside and outside the nanocages. The layers are grown on palladium nanocrystal templates, and then the palladium is etched away to leave behind nanocages approximately 20 nanometers in diameter, with between three and six atom-thin layers of platinum. Use of these nanocage structures in fuel cell electrodes could increase the utilization efficiency of the platinum by a factor of as much as seven, potentially changing the economic viability of the fuel cells.

A transmission electron microscope image shows a typical sample of platinum cubic nanocages

We can get the catalytic activity we need by using only a small fraction of the platinum that had been required before,” said Younan Xia, a professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. Xia also holds joint faculty appointments in the School of Chemistry and Biochemistry and the School of Chemical and Biomolecular Engineering at Georgia Tech. “We have made hollow nanocages of platinum with walls as thin as a few atomic layers because we don’t want to waste any material in the bulk that does not contribute to the catalytic activity.
The research – which also involved researchers at the University of Wisconsin-Madison, Oak Ridge National Laboratory, Arizona State University and Xiamen University in China – was reported in the July 24 issue of the journal Science.


New Cheap Catalyst For Hydrogen Electric Car

Graphene nanoribbons formed into a three-dimensional aerogel and enhanced with boron and nitrogen are excellent catalysts for fuel cells, used in hydrogen electric car, even in comparison to platinum, according to Rice University researchers. The reactions in most current fuel cells are catalyzed by platinum, but platinum’s high cost has prompted the search for alternative. A team led by materials scientist Pulickel Ajayan and chemist James Tour made metal-free aerogels from graphene nanoribbons and various levels of boron and nitrogen to test their electrochemical properties. In tests involving half of the catalytic reaction that takes place in fuel cells, they discovered versions with about 10 percent boron and nitrogen were efficient in catalyzing what’s known as an oxygen reduction reaction, a step in producing energy from feedstocks like methanol.
Ajayan’s Rice lab has excelled in turning nanostructures into macroscopic materials, like the oil-absorbing sponges invented in 2012 or, more recently, solid nanotube blocks with controllable densities and porosities.

hydrogen-electric car
The key to developing carbon-based catalysts is in the doping process, especially with elements such as nitrogen and boron,” he said. “The graphitic carbon-boron-nitrogen systems have thrown many surprises in recent years, especially as a viable alternative to platinum-based catalysts.”. The Rice process is unique, he said, because it not only exposes the edges but also provides porous conduits that allow reactants to permeate the material.
The research appeared in the American Chemical Society journal Chemistry of Materials.


Electric Car: Hydrogen Fuel Cells 40 Times Cheaper

Researchers from Umea University – Sweden – and chinese collegues show how a unique nano-alloy composed of palladium nano-islands embedded in tungsten nanoparticles creates a new type of catalysts for highly efficient oxygen reduction, the most important reaction in hydrogen fuel cells. Fuel cell systems represent a promising alternative for low carbon emission energy production. Traditional fuel cells are however limited by the need of efficient catalysts to drive the chemical reactions involved in the fuel cell. Historically, platinum and its alloys have frequently been used as anodic and cathodic catalysts in fuel cells, but the high cost of platinum, due to its low abundance, motivates researchers to find efficient catalysts based on earth-abundant elements. The explanation for the very high efficiency is the unique morphology of the alloy. It is neither a homogeneous alloy, nor a fully segregated two-phase system, but rather something in between.

hydrogen fuel cellsCaption: A schematic model of the unique morphology of the alloy. The Pd-islands (light-brown spheres) are embedded in an environment of tungsten (blue spheres). Oxygen are represented by red spheres, and hydrogen by white spheres.

In our study we report a unique novel alloy with a palladium (Pd) and tungsten (W) ratio of only one to eight, which still has similar efficiency as a pure platinum catalyst. Considering the cost, it would be 40 times lower,” says Thomas Wågberg, Senior lecturer at Department of Physics, Umeå University.
The unique formation of the material is based on a synthesis method, which can be performed in an ordinary kitchen micro-wave oven purchased at the local supermarket. If we were not using argon as protective inert gas, it would be fully possible to synthesize this advanced catalyst in my own kitchen! ,” says Thomas Wågberg.
The findings are published in the scientific journal Nature Communications.


Electric Car New Battery 10 times More Powerful

Los Alamos National Laboratory scientists have designed a new type of nanostructured-carbon-based catalyst that could pave the way for reliable, economical next-generation batteries and alkaline fuel cells, providing for practical use of wind– and solar-powered electricity, as well as enhanced hybrid electric vehicles. Los Alamos researchers Hoon T. Chung, Piotr Zelenay and Jong H. Won, the latter now at the Korea Basic Science Institute, describe a new type of nitrogen-doped carbon-nanotube catalyst. The new material has the highest oxygen reduction reaction (ORR) activity in alkaline media of any non-precious metal catalyst developed to date. This activity is critical for efficient storage of electrical energy. The new catalyst doesn’t use precious metals such as platinum, which is more expensive per ounce than gold, yet it performs under certain conditions as effectively as many well-known and prohibitively expensive precious-metal catalysts developed for battery and fuel-cell use. Moreover, although the catalyst is based on nitrogen-containing carbon nanotubes, it does not require the tedious, toxic and costly processing that is usually required when converting such materials for catalytic use.

These findings could help forge a path between nanostructured-carbon-based materials and alkaline fuel cells, metal-air batteries and certain electrolyzers,” said Zelenay. “A lithium-air secondary battery, potentially the most-promising metal-air battery known, has an energy storage potential that is 10 times greater than a state-of-the-art lithium-ion battery. Consequently, the new catalyst makes possible the creation of economical lithium-air batteries that could power electric vehicles, or provide efficient, reliable energy storage for intermittent sources of green energy, such as windmills or solar panels.

The research hax been published in a paper appearing recently in Nature Communications.