High surface area perovskite materials as functional catalyst supports for glycerol oxidation

• High surface area perovskite materials were synthesised using a hard templating methodology with SBA-15 • Perovskite materials, LaBO 3 (where B = Cr, Mn, Fe, Co and Ni), were used as supports for 1 wt% AuPt nanoparticles • Support properties could be used to tune product distribution to lactic acid, glyconic acid or tartronic acid A series lanthanum perovskite supports (LaBO 3 , where B = Cr, Mn, Fe, Co and Ni) were synthesised using a hard templating methodology with a mesoporous silica template (SBA-15). This methodology produced high surface area perovskites with surface areas of 70–160 m 2 g −1 . 1 wt% AuPt was added to the perovskite supports using sol immobilisation and the resultant catalysts tested for the oxidation of glycerol. When the AuPt/LaBO 3 catalysts were tested for glycerol oxidation the product distributions via either the oxidation mechanism or a dehydration mechanism could be tuned by substituting different transition metals into the B site. In line with previous studies, AuPt/LaMnO 3 and AuPt/LaCoO 3 gave the highest yield of oxidation products (glyceric acid with small amounts of tartronic acid), AuPt/LaCrO 3 gave the highest yield of lactic acid through the dehydration pathway, while AuPt/LaNiO 3 and AuPt/LaFeO 3 gave a mixture of products from both the oxidation and dehydration pathways. The product distributions were found to change over the course of the reaction due to the relative rates of the two reaction pathways. For all catalysts except AuPt/LaMnO 3 the yield of oxidation products stopped after two hours, while all catalysts except AuPt/LaMnO 3 continued to produce lactic acid over the whole reaction. This suggests the perovskite supported catalysts are not stable over the course of the reaction. The most interesting behaviour was found for the AuPt/LaFeO 3 catalyst that gave a high initial selectivity to tartronic acid, although further studies are needed to elucidate the mechanism fully.