VO(x)/Fe(2)O(3) Shell–Core Catalysts for the Selective Oxidation of Methanol to Formaldehyde

Efficient oxidation catalysts are important in many current industrial processes, including the selective oxidation of methanol to formaldehyde. Vanadium-containing catalysts have been shown to be effective selective oxidation catalysts for certain reactions, and research continues to examine their applicability to other reactions of interest. Several VO(x)/Fe(2)O(3) shell–core catalysts with varying VO(x) coverage have been produced to investigate the stability of VO(x) monolayers and their selectivity for methanol oxidation. Catalyst formation proceeds via a clear progression of distinct surface species produced during catalyst calcination. At 300 °C the selective VO(x) overlayer has formed; by 500 °C a sandwich layer of FeVO(4) arises between the VO(x) shell and the Fe(2)O(3) core, inhibiting iron cation participation in the catalysis and enhancing catalyst selectivity. The resulting catalysts, comprising a shell–subshell–core system of VO(x)/FeVO(4)/Fe(2)O(3), possess good catalytic activity and selectivity to formaldehyde. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11244-017-0873-2) contains supplementary material, which is available to authorized users.