With carbon dioxide from the American energy sector plummeting back to early 1990s levels and coal, the dirtiest energy source, back at early 1980s levels, environmentalists have tried to turn on natural gas and its primary component, methane.

Don't be fooled. Other sources, like solar, are not ready yet, wind never will be and nuclear science is reviled by Democrats so methane is the best bridge to the future (which will eventually be solar).  A new technique transforms the delightful stinky, air-polluting landfill gas into a hydrogen fuel cell, according to a presentation at National Meeting of the American Chemical Society.

Hydrogen has been long studied as a clean alternative to fossil fuels, which release carbon dioxide — the main greenhouse gas — when burned. Hydrogen only emits water vapor when it is burned. While methane and natural gas are ideal for clean energy generation, for portable applications, like automobiles, a hydrogen fuel cell would be beneficial.




Researchers have devised a catalyst that could one day turn the smelly gases at this landfill in Niterói, Brazil, into clean hydrogen fuel. Credit: Luiz Almeida

One way to do this is to convert methane, another greenhouse gas, to hydrogen by reacting it with carbon dioxide. And smelly landfills are excellent sources of these gases — microbes living in the waste produce large amounts of methane and carbon dioxide as by-products.

But researchers have faced challenges bringing this idea to reality. For example, finding a proper catalyst has been a major hurdle, says Fabio B. Noronha, Ph.D., who is with the National Institute of Technology in Rio de Janeiro, Brazil. A catalyst is a substance that speeds up processes that otherwise would occur slowly. In this case, researchers are using catalysts to help turn methane and carbon dioxide into hydrogen and carbon monoxide. The problem is that carbon, which forms as a contaminant during the process, deposits onto the catalyst.

"The heart of the process for the production of hydrogen from landfill gas is the catalyst, and this can be disrupted by the presence of carbon," Noronha explains. "Because of carbon deposition, the catalyst loses the capacity to convert the landfill gases into hydrogen."

He says that to solve this problem, Noronha's team developed a new catalyst material that removes the carbon as soon as it is formed. This approach is based on the automotive catalysts developed in the past to control car and truck emissions, he adds. The material is a perovskite-type oxide supported on ceria, which is a component of ceramics.

Right now, the researchers are working on the reaction in the laboratory, but the new, highly stable catalyst should be ideal for commercialization. As a step in that direction, the team plans to test it on a larger scale using material from a local landfill, says Noronha.



Source: ACS