In an attempt to make liquid fuels more energy efficient, scientists have found that adding aluminum or aluminum oxide nanoparticles to diesel fuel improves its ignition properties (Nano Lett., DOI: 10.1021/nl080277d). In simple hot-plate experiments, Arizona State University mechanical engineer Patrick E. Phelan and coworkers found that diesel fuel containing 0.1% aluminum or aluminum oxide nanoparticles ignites more readily at lower temperatures than pure diesel. The researchers suspect that adding nanoparticles to diesel improves the fuel's radiative properties and its heat- and mass-transfer capabilities. The nanoparticles increase the probability that a single drop of the fuel will ignite at just above 700 ??C. The probability increases from about 15% for pure diesel to between 50 and 60% for nanoparticle-enriched diesel. Phelan's group also looked at two different sizes of Al2O3 particles and found that 50-nm particles were slightly better at getting diesel to ignite than 15-nm particles but only at the lower range of temperatures tested. Envirox, a cerium oxide-based catalyst nanoparticle that's reported to boost fuel efficiency, is already on the market from nanomaterials firm Oxonica.