The interaction of copper-containing spinels CuFe2O4 and CuFeCrO4 with hydrogen

The interaction of hydrogen with copper-containing spinels CuFe2O4 and CuFeCrO4, which are the catalysts for hydrogenation, alkylation and other reactions, was studied. Copper ions of ferrite are reduced in a reductive atmosphere and segregated to the spinel Fe3O4 surface with the formation of Cu-0 nanoparticles; their interaction with O-2-contaning (less than 1 vol.%) helium leads to the oxidation to Cu2O or CuO. In a reductive medium, copper ferrite-chromite CuFeCrO4 segregates copper ions from spinel, which are reduced to Cu-0 nanoparticles on the surface of CuFeCr-spinel. Charge compensation of spinel structure occurs due to formation of OH groups and by the partial transition Fe3+ -Fe2+. Upon mild reoxidation, Cu-0 atoms partially return into the spinel structure and partially form the Cu2O phase.