Renewable energy sources, fuel cells

If hydrogen is made from decarbonized fossil fuels, fuel-cycle emissions can be cut by up to 80 percent. With renewable energy sources such as biomass, solar, or wind, the fuel cycle greenhouse gas emissions are virtually eliminated. It is possible to envision a future energy system based on hydrogen and fuel cells with little or no emissions of pollutants or greenhouse gases in fuel production, distribution, or use. 

The scope of this chapter is to present a concise and fundamental overview of the relationship between modem catalysis and chemical reaction engineering through one of the topics that will certainly be present among the future directions in both fields production of hydrogen fuel from fossil and renewable energy sources and its use in the fuel cells-based energy conversion technology. 

Scientific interest in nanocarbon hybrid materials to enhance the properties of photocatalysts and photoactive electrodes has been growing rapidly [1-8]. The worldwide effort to find new efficient and sustainable solutions to use renewable energy sources has pushed the need to develop new and/or improved materials able to capture and convert solar energy, for example in advanced dye-sensitized solar cells - DSSC (where the need to improve the photovoltaic performance has caused interest in using nanocarbons for a better cell design [9,10]) or in advanced cells for producing solar fuels [11-13]. 

Alternative fuels can be used to power a fuel cell such as hydrogen, methane, natural gas, methanol, ethanol, liquehed petroleum gas and landfill gas, which can be produced from renewable energy sources such as biomass and wind. 

A second workshop, Catalysis for Sustainable Energy Production , was held in Sesto Fiorentino (Florence, Italy) from 29 November to 1 December 2006. The structure and approach of this workshop were similar to those of the first, but the focus was on (i) fuel cells, (ii) hydrogen and methane storage and (iii) H2 production from old to new processes, including those using renewable energy sources. The present book is based on this second workshop and reports a series of invited contributions which provide both the state-of-the-art and frontier research in the field. Many contributions are from industry, but authors were also asked to focus their description on the identification of priority topics and problems. The active discussions during the workshop are reflected in the various chapters of this book. 

The high energy conversion efficiency of solid oxide fuel cells (SOFC), together with their high fuel flexibility, make them an ideal candidate for a better exploitation of fossil fuels, and for an efficient conversion of renewable energy sources into electricity. 

These fuels (pure H2, H2/C02, and H2/C0/C02) can also be produced from renewable energy sources—biomass, solar, windmills, and hydroelectric power. On the other hand, pure H2 can be generated by water electrolysis using nuclear power plants. Hydrogen is the most electro-reactive fuel for fuel cells operating at low and intermediate temperatures. 

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