Functional sample of large-area (5x5 cm2) thin-film catalyst coated membrane with fiber-like structure
Abstract
Sputter-etching modification of proton-exchange membrane leads to formation of fiber-like structure on its surface. This structure is consequently capable of carrying thin-film catalyst over its significantly enlarged surface without the need of any additional supporting nanoparticles.
Catalyst coated membrane (CMM) prepared by this procedure performs comparably to standard commercial CCMs which however rely on 10times higher surface density of noble metals. In order to demonstrate the application potential of the sputter-etched CCM in kW-range electrolyzers, large-area (5x5 cm2) functional samples were prepared as a natural scale up of previously tested and proven lab-size samples.
Complex optimization steps regarding the deposition geometry, pressure, power density etc. were carried out to obtain the same morphological and electrochemical characteristics over the much larger area. Functional samples were prepared within a single vacuum entry (simulating industrial preparation) during which the membrane underwent surface modification and also consequent catalyst deposition.
Functional samples with 10times less noble metal loading performed similarly to standard commercial CCMs when used in kW-range water electrolyzer stack.