Iron-doped Co3O4 catalysts prepared by a surfactant-assisted method as effective catalysts for malic acid oxidative decarboxylation

Abstract

Iron-doped Co₃O₄ oxides prepared by a surfactant-assisted method exhibited good catalytic activity in malic acid conversion, and the oxygen defects associated with the presence of Co²⁺ 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 (Fe³⁺ replaces Co²⁺ from tetrahedral sites, while Fe²⁺ replaces Co³⁺ 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 Co²⁺ loading showed the highest yield of pyruvic acid.