This lecture discusses the recent advances in catalytic steam reforming of liquid fuels for fuel cell applications. Liquid hydrocarbon fuels are high-density fuels that are widely available for fuel cell applications, but the higher hydrocarbons can cause coke formation and the organic sulfur leads to sulfur poisoning of the catalysts. Thus a major challenge is to develop sulfur-tolerant and carbon-resistant catalysts for steam reforming of liquid hydrocarbon fuels at low-temperature for fuel cells. Rhodium catalysts are active for low-temperature steam reforming of hydrocarbons but are easily poisoned by sulfur. Nickel catalysts are widely used for natural gas reforming for hydrogen production but suffer from quick coking with higher hydrocarbon feeds. We have proposed a design concept for new bimetallic catalysts and conducted a series of experimental work coupled with analytical characterization. Loading ceria on alumina was found to improve the steam adsorption and activation and resist coke formation. Adding nickel to rhodium was found to improve catalytic activity for hydrocarbon activation and also protect rhodium from sulfur poisoning. These findings led to the development of sulfur-tolerant and carbon-resistant bimetallic catalysts supported on CeO2-modified Al2O3 support for fuel cells. More background information is available in recent publications [C.S. Song, Catal. Today 2002 (77) 17; J.J. Strohm at al., J. Catal. 2006, 238 (2) 309; Y. Li et al., Appl. Catal A: Gen. 2009 (357) 213]. Recent advances in our laboratory will be discussed on the sulfur-tolerant and carbon-resistant catalysts for low-temperature steam reforming of liquid hydrocarbon fuels. New spectroscopic study on the nature of sulfur species and carbon species on the used reforming catalysts will also be briefly described, which provides new insight on the origin of sulfur tolerance and carbon resistance of monometallic and bimetallic catalysts.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)