According to reports, researchers at Cornell University (Cornell University) in the United States have found that a nitrogen-and carbon-coated nickel anode can catalyze an important reaction in hydrogen fuel cells at a cost of only a fraction of the precious metals currently used.
The new discovery could accelerate the widespread use of hydrogen fuel cells. As a kind of efficient and clean energy, hydrogen fuel cell has a great prospect in automobile and other application fields. This is one of a series of discoveries by the H é ctor D. Abru ñ a laboratory, which is looking for active, cheap and durable catalysts used in alkaline fuel cells.
"this discovery has made progress in using efficient and clean hydrogen fuel cells to replace fossil fuels," the researchers said. " The study was recently published in the Proceedings of the National Academy of Sciences.
At present, hydrogen fuel cells require expensive precious metals, such as platinum, to effectively catalyze the reactions they use to generate electricity. Although alkaline polymer electrolyte membrane fuel cell (APEMFC) can use non-precious metal electrocatalysts, they lack the necessary performance and durability to replace precious metal-based systems.
Fuel cells generate electricity through hydroxide reaction (HOR) and oxygen reduction reaction (OOR). Platinum is a typical catalyst for both reactions because it catalyzes them effectively and is durable in the acidic environment of proton exchange membrane fuel cells, the researchers said.
What about the other materials? Recent experiments with non-precious metal HOR electrocatalysts need to overcome two main challenges: low inherent activity due to strong hydrogen bond energy and poor durability due to rapid passivation of metal oxides, the researchers wrote.
To overcome these challenges, the researchers designed a nickel-based electrocatalyst with a 2-nanometer shell made of nitrogen-doped carbon.
Their hydrogen fuel cell has an anode (where hydrogen is oxidized) a catalyst consisting of a solid nickel core surrounded by a carbon shell. When paired with a cobalt-manganese cathode (oxygen is reduced), the resulting hydrogen fuel cell, which is completely free of precious metals, produces an output of more than 200 milliwatts per square centimeter.
The presence of nickel oxides on the surface of nickel electrodes greatly slows down the hydroxidation reaction, the researchers said. The nitrogen-doped carbon coating acts as a protective layer, enhances the HOR kinetics, and makes the reaction faster and more efficient.
In addition, the existence of graphene coating on the nickel electrode prevents the formation of nickel oxide, which greatly improves the life of the electrode. These electrodes are also much more tolerant to carbon monoxide, which quickly "poisons" platinum.
"the use of this new anode will greatly reduce the price and enable alkaline fuel cells to be used in a wider range of fields." They added.
