Highly Stable Apatite Supported Molybdenum Oxide Catalysts for Selective Oxidation of Methanol to Formaldehyde: Structure, Activity and Stability

Molybdenum oxide (5 to 20 wt.%) supported on calcium or strontium hydroxyapatite were investigated as catalysts for selective oxidation of methanol formaldehyde. These both active and selective, with a maximum yield achieved at 95 % conversion 96 selectivity. The main byproducts CO (3.2 %) dimethyl ether (DME, 0.7 %). catalytic performance the was measured up 600 h 350 °C. Compared an industrial iron molybdate catalyst, based deactivated slower. species found be surface layer MoOx support, while excess molybdenum formed crystalline (Ca/Sr)MoO4, acting reservoir replenishing lost by volatilization methanol. in form (Ca/Sr)MoO4 volatilize significantly slower than MoO3 catalysts. combination high activity selectivity low rate Mo makes this class interesting production