The present invention relates to water-based catalyst inks and their use
for manufacture of catalyst-coated substrates. According to the present
invention, a catalyst layer is applied to the hydrophobic surface of a
substrate by using a water-based catalyst ink comprising an
electrocatalyst, an ionomer and water. The catalyst ink also comprises a
highly volatile surfactant having a vapor pressure at ambient temperature
in the range of 1 to 600 Pa. The use of this surfactant allows applying
the water-based ink to the hydrophobic surface of a variety of substrates,
such as gas diffusion layers, advanced ionomer membranes and polymer
substrates. The required coating deposit can be applied in one coating
pass and the resulting catalyst layer exhibits improved performance due to
the absence of residual surfactant in the catalyst layer.
