Iron-doped Co 3 O 4 catalysts prepared by a surfactant-assisted method as effective catalysts for malic acid oxidative decarboxylation

Iron-doped Co 3 O 4 oxides prepared by a surfactant-assisted method exhibited good catalytic activity in malic acid conversion, and the oxygen defects associated with the presence of Co 2+ played a key role in catalyst activation for pyruvic acid production. The most active catalyst, for which the malic acid conversion was 70% and the pyruvic acid yield was 24%, has an inverse spinel type structure (Fe 3+ replaces Co 2+ from tetrahedral sites, while Fe 2+ replaces Co 3+ from octahedral sites) as well as a small energy difference between the highest occupied orbital and the lowest unoccupied orbital (low band-gap, E g ). The catalyst with the highest Co 2+ loading showed the highest yield of pyruvic acid.