Thursday, February 20, 2014

New Solar Fuel Cell Runs On Biomass

Georgia Institute of Technology, U.S.A., has come out of a new fuel cell design that incorporates solar thermal energy, enabling it to use woody biomass, algae, and even chicken waste for energy input instead of relying on hydrogen gas. The non-hydrogen angle is significant because hydrogen gas is expensive and energy-intensive to produce.

The idea of using biomass to run a fuel cell is nothing new. The only problem is that to break down the carbon bonds in natural polymers you need a catalyst which involves expensive precious metals, like platinum.

The key in the design is the use of inexpensive transition metals called POM (Polyoxometalate) catalyst. POM is both a photochemical (chemical interaction with light) and a thermochemical (chemical interaction with heat) catalyst. When mixed in a solution with ground-up biomass and exposed to sunlight or heat, it then oxidizes the biomass and delivers the charges from the biomass to the fuel cell’s anode. The electrons are then transported to the cathode, where they are finally oxidized by oxygen through an external circuit to produce electricity.

POM catalyst is durable and can be re-used without re-treatment, which helps to cut costs. Another advantage of POM-biomass mixture is that it is inert at room temperature (in the absence of sunlight or heat) which helps to reduce storage cost.

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