This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Hydrogen-powered cars, power stations and portable chargers all rely on fuel cells. At the heart of each fuel cell is a catalyst that speeds up the reaction between hydrogen and oxygen to produce electricity and water.
These catalysts are typically made of platinum—which costs nearly as much as gold. Researchers from Southern Federal University, together with colleagues from Skoltech (part of the VEB.RF Group), the Institute of Catalysis of the Siberian Branch of the Russian Academy of Sciences, and Bauman Moscow State Technical University, have found a way to make this key component both cheaper and better. They developed a catalyst from a five-metal alloy that retains its activity even after 10,000 operating cycles.
Fuel cell catalysts are made from platinum because it is the most efficient metal for the job—but also the most expensive. To bring down the cost, platinum is alloyed with other, more affordable metals. In this study, the researchers used a combination of five elements: platinum, palladium, copper, nickel and cobalt.
The chemists at Southern Federal University devised a straightforward and scalable method to synthesize small five-component metallic nanoparticles evenly distributed on a carbon support. In practice, however, such materials often come out uneven: Some metals remain in an oxidized state, and atoms are distributed nonuniformly. To fix this, the material is heat-treated.
For the first time, the scientists observed in real time what happens to the alloy nanoparticles as they are heated from 300 to 600°C (572 to 1,112°F). At different temperatures, different effects occur, altering the microstructure and electrochemical performance of the catalyst. Above 400°C (752°F), for instance, the alloy begins to restructure, and its surface becomes enriched with platinum—and since platinum is what drives the reaction, this enrichment boosts the catalyst's effectiveness.
Skoltech researchers carried out computer simulations that confirmed that platinum does indeed migrate to the nanoparticle surface: At 600°C (1,112°F), about 75% of all platinum atoms end up in the outermost layer. Palladium, by contrast, moves deeper into the particle. As a result, the heat-treated catalyst performs better, even though its active surface area shrinks slightly due to particle growth.
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