Hydrogen as an everyday, environmentally friendly fuel source may be closer than we think, according to Penn State researchers.
"The energy focus is currently on ethanol as a fuel, but economical ethanol from cellulose is 10 years down the road," says Bruce E. Logan, the Kappe professor of environmental engineering. "First you need to break cellulose down to sugars and then bacteria can convert them to ethanol."
Logan and Shaoan Cheng, research associate, suggest a method based on microbial fuel cells to convert cellulose and other biodegradable organic materials directly into hydrogen.
The researchers used naturally occurring bacteria in a microbial electrolysis cell with acetic acid -- the acid found in vinegar. Acetic acid is also the predominant acid produced by fermentation of glucose or cellulose. The anode was granulated graphite, the cathode was carbon with a platinum catalyst, and they used an off-the-shelf anion exchange membrane. The bacteria consume the acetic acid and release electrons and protons creating up to 0.3 volts. When more than 0.2 volts are added from an outside source, hydrogen gas bubbles up from the liquid.
"This process produces 288 percent more energy in hydrogen than the electrical energy that is added to the process," says Logan.