Additional: Collaborations , EERE , International Collaboration. A new experiment determines the energy available to drive chemical reactions at the interface between an illuminated semiconductor and a liquid solution.

Ligand design and electrochemical studies pave a new path toward stable high-valent mid-actinide complexes. Thank you for visiting our site. We hope your visit was informative and enjoyable. Breadcrumb Navigation Home Programs Basic Energy Sciences BES Science Highlights Improved Fuel Cell Catalysts with Less Platinum.

Improved Fuel Cell Catalysts with Less Platinum A new catalyst design meets cost, activity, and durability goals by leveraging ultralow loadings of platinum with platinum-free supports. Image courtesy of Argonne National Laboratory An artistic rendition of the synergistic catalyst showing core-shell active sites blue in platinum-cobalt nanoparticles spheres on a platinum group metal-free catalytic support.

The Science Scientists have identified highly active yet stable catalysts for use in fuel cells that contain only a quarter of the platinum as compared to existing devices. The Impact Proton-exchange membrane fuel cells PEMFCs are highly efficient. Summary Innovative approaches for reducing the amount of platinum in catalysts, while maintaining the high activity and stability that platinum provides, are of intense interest.

Contact Jianguo Wen Center for Nanoscale Materials and Argonne National Laboratory jwen anl. gov ; Maria K. gov ; Di-Jia Liu Argonne National Laboratory djliu anl. gov ; Funding This work was supported by the Department of Energy DOE Fuel Cell Technologies Office through the Office of Energy Efficiency and Renewable Energy; the DOE Office of Basic Energy Sciences, Chemical, Biological, and Geosciences Division; the DOE Office of Science Graduate Student Research program; the National Key Research and Development Program of China; and the Chinese National Nature Science Foundation.

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Measurement Technique Sheds New Light on Semiconductors for Solar Fuels A new experiment determines the energy available to drive chemical reactions at the interface between an illuminated semiconductor and a liquid solution. To Study Radioactive Neptunium and Plutonium, Researchers Establish a Novel Chemistry Ligand design and electrochemical studies pave a new path toward stable high-valent mid-actinide complexes.

Contact Basic Energy Sciences Address BES, Germantown Building U. Department of Energy Independence Ave. In the quest for better, less expensive ways to store and use energy, platinum and other precious metals play an important role. They serve as catalysts to propel the most efficient fuel cells, but they are costly and rare.

Now, a metal-free alternative catalyst for fuel cells may be at hand. In a study published July 15 in ACS Central Science , a team of chemists from the University of Wisconsin—Madison introduces a new approach that uses a molecular catalyst system instead of solid catalysts.

Although molecular catalysts have been explored before, earlier examples were much less efficient than the traditional platinum catalyst. A fuel cell converts chemical energy into electricity by reacting hydrogen and oxygen at two different electrodes. A catalyst makes the reaction more efficient.

They noticed a striking similarity between these aerobic oxidation reactions and the oxygen reaction in fuel cells and decided to see if they could apply a similar approach to a fuel cell.

The new catalyst is composed of a mixture of molecules called nitroxyls and nitrogen oxides. In order to provide a cell with energy, these molecules have to pass across the cell membrane, which functions as a barrier — but not an impassable one.

Like the exterior walls of a house, the plasma membrane is semi-permeable. In much the same way that doors and windows allow necessities to enter the house, various proteins that span the cell membrane permit specific molecules into the cell, although they may require some energy input to accomplish this task Figure 2.

Figure 2: Cells can incorporate nutrients by phagocytosis. This amoeba, a single-celled organism, acquires energy by engulfing nutrients in the form of a yeast cell red. Through a process called phagocytosis, the amoeba encloses the yeast cell with its membrane and draws it inside.

Specialized plasma membrane proteins in the amoeba in green are involved in this act of phagocytosis, and they are later recycled back into the amoeba after the nutrients are engulfed. Figure Detail.

Complex organic food molecules such as sugars, fats, and proteins are rich sources of energy for cells because much of the energy used to form these molecules is literally stored within the chemical bonds that hold them together.

Scientists can measure the amount of energy stored in foods using a device called a bomb calorimeter. With this technique, food is placed inside the calorimeter and heated until it burns. The excess heat released by the reaction is directly proportional to the amount of energy contained in the food.

Figure 3: The release of energy from sugar Compare the stepwise oxidation left with the direct burning of sugar right. Through a series if small steps, free energy is released from sugar and stored in carrier molecules in the cell ATP and NADH, not shown.

On the right, the direct burning of sugar requires a larger activation energy. In this reaction, the same total free energy is released as in stepwise oxidation, but none is stored in carrier molecules, so most of it will be lost as heat free energy.

This direct burning is therefore very inefficient, as it does not harness energy for later use. In reality, of course, cells don't work quite like calorimeters. Rather than burning all their energy in one large reaction, cells release the energy stored in their food molecules through a series of oxidation reactions.

Oxidation describes a type of chemical reaction in which electrons are transferred from one molecule to another, changing the composition and energy content of both the donor and acceptor molecules.

Food molecules act as electron donors. During each oxidation reaction involved in food breakdown, the product of the reaction has a lower energy content than the donor molecule that preceded it in the pathway.

At the same time, electron acceptor molecules capture some of the energy lost from the food molecule during each oxidation reaction and store it for later use. Eventually, when the carbon atoms from a complex organic food molecule are fully oxidized at the end of the reaction chain, they are released as waste in the form of carbon dioxide Figure 3.

Cells do not use the energy from oxidation reactions as soon as it is released. Instead, they convert it into small, energy-rich molecules such as ATP and nicotinamide adenine dinucleotide NADH , which can be used throughout the cell to power metabolism and construct new cellular components.

In addition, workhorse proteins called enzymes use this chemical energy to catalyze, or accelerate, chemical reactions within the cell that would otherwise proceed very slowly.

Enzymes do not force a reaction to proceed if it wouldn't do so without the catalyst; rather, they simply lower the energy barrier required for the reaction to begin Figure 4.

Figure 4: Enzymes allow activation energies to be lowered. Enzymes lower the activation energy necessary to transform a reactant into a product. On the left is a reaction that is not catalyzed by an enzyme red , and on the right is one that is green. In the enzyme-catalyzed reaction, an enzyme will bind to a reactant and facilitate its transformation into a product.

Consequently, an enzyme-catalyzed reaction pathway has a smaller energy barrier activation energy to overcome before the reaction can proceed.

Figure 5: An ATP molecule ATP consists of an adenosine base blue , a ribose sugar pink and a phosphate chain. The high-energy phosphate bond in this phosphate chain is the key to ATP's energy storage potential.

Figure Detail The particular energy pathway that a cell employs depends in large part on whether that cell is a eukaryote or a prokaryote. Eukaryotic cells use three major processes to transform the energy held in the chemical bonds of food molecules into more readily usable forms — often energy-rich carrier molecules.

Adenosine 5'-triphosphate, or ATP, is the most abundant energy carrier molecule in cells. This molecule is made of a nitrogen base adenine , a ribose sugar, and three phosphate groups.

The word adenosine refers to the adenine plus the ribose sugar. The bond between the second and third phosphates is a high-energy bond Figure 5. The first process in the eukaryotic energy pathway is glycolysis , which literally means "sugar splitting.

Glycolysis is actually a series of ten chemical reactions that requires the input of two ATP molecules. This input is used to generate four new ATP molecules, which means that glycolysis results in a net gain of two ATPs. Two NADH molecules are also produced; these molecules serve as electron carriers for other biochemical reactions in the cell.

Glycolysis is an ancient, major ATP-producing pathway that occurs in almost all cells, eukaryotes and prokaryotes alike. This process, which is also known as fermentation , takes place in the cytoplasm and does not require oxygen. However, the fate of the pyruvate produced during glycolysis depends upon whether oxygen is present.

Catalyst materials can be manufactured either in black also known as pure form or in the supported form. Black or pure form of the catalytic materials would usually have lower surface area compared to their supported counterparts.

Carbon has been the most promising support material due to its extremely large surface area, good electrical conductivity, and inherent inertness in fuel cell devices. FuelCellStore supplies the following catalytic materials due to their most common use in electrochemical devices: platinum based catalysts, platinum ruthenium based catalysts, palladium based catalysts, iridium based catalysts and other catalysts Ag, Au, Co, Cu, Fe, Ni, Rh, Ru, and Sn.

Generally, in a polymer electrolyte membrane fuel cell PEMFC or proton exchange membrane fuel cell , platinum black or platinum supported on carbon are used as the catalyst both for anode and cathode sides. In PEM electrolyzers, iridium ruthenium oxide, iridium oxide, iridium black, platinum black can be used as the anode catalyst.

For the cathode side of the electrolyzers, platinum black or platinum supported on carbon catalysts can be used. Direct methanol fuel cell DMFC requires the addition of ruthenium as a catalyst to the platinum also called as platinum-ruthenium alloy in order to facilitate the electrochemical oxidation of alcohol fuel.

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Palladium Based Catalysts. Iridium Based Catalysts. Other Catalysts. Carbon Powders. Catalyst Additives. Show: 15 25 50 75 Loukrakpam, S. Lim, L. Wang, B. Fang and Z.

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Issue 4, Fuelcell technology: nano-engineered multimetallic catalysts. Njoki , a Derrick Mott , a Bridgid Wanjala , a Rameshwori Loukrakpam , a Stephanie Lim , a Lingyan Wang , a Bin Fang a and Zhichuan Xu a.

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