Fuel Cell Earth offers several products for your catalyst backing layer. Carbon paper and Carbon Cloth.For Paper we offer AvCarb and Toray carbon paper, Our AvCarb carbon paper can be purchased untreated or Teflon treated with various percentages of Teflon.Toray paper is only available Teflon treated. We also offer a high quality carbon cloth material both Teflon treated or untreated. Teflon gives the carbon material a hydrophobic property to better function as an electrode backing material.