Active and durable copper phosphate catalysts modified with metal oxides for methane oxidation with oxygen into formaldehyde

Abstract

Copper phosphates as active catalysts for methane oxidation with O₂ into formaldehyde were deposited on silica supports or dispersed with aluminum oxides in order to enhance their catalytic performance. Deposition of copper phosphates on silica led to the formation of α-Cu₂P₂O₇ crystallites with small sizes, which improved the formaldehyde yield in the methane oxidation with O₂. The addition of aluminum oxides into copper phosphates resulted in the formation of Cu₃(PO₄)₂ and α-Cu₂P₂O₇. These copper phosphates diluted with aluminum oxides showed high durability for the formaldehyde formation in the methane oxidation with O₂ at 923 K. These modifications of the catalysts with silica supports or alumina additives resulted in the formation of small copper phosphates crystallites and the modification of the redox performance of copper phosphates.