CATALYST

Catalyst material comprising nanoparticles dispersed within a metal oxide layer, the metal oxide layer comprises metal oxide comprising at least one metal cation, wherein the nanoparticles comprise Pt, wherein the nanoparticles comprise less than 10 atom % of oxygen, and wherein the metal oxide layer has an average thickness not greater than 50 nanometers. The catalyst material comprising nanoparticles dispersed within a metal oxide layer can be converted, for example, to nanoporous catalyst layer comprising nanoparticles fused together, wherein the nanoparticles comprise Pt, wherein the nanoparticles comprise less than 10 atom % of oxygen, and wherein the layer has an average thickness not greater than 50 nanometers. The nanoporous catalyst layer is useful, for example, in fuel cell membrane electrode assemblies.