Chemical looping methanol oxidation using supported vanadium phosphorous oxide carriers for formaldehyde production

This work describes the remarkable performance of a novel chemical looping route for the partial oxidation of methanol to formaldehyde employing beta-VOPO4 as the oxygen carrier. During reduction, the VOPO4 carrier donates its lattice oxygen to methanol, generating formaldehyde and steam. The reduced carrier, VPO5-x, subsequently replenishes its lattice oxygen by reacting with air during oxidation. This study explores how incorporating VOPO4 on SiO2 support enables superior lattice oxygen utilization owing to improved active site dispersion. Subsequently, a stable redox performance over 10 redox cycles is achieved for the synthesized carrier. Fixed bed studies showcased a stable methanol conversion of 85% with a corresponding formaldehyde selectivity of 45%. These results confirm the feasibility of VOPO4-based oxygen carrier design for the selective oxidation of methanol to formaldehyde. The insights on carrier development targeted for selective reaction provided in this work can also be leveraged for advancing other chemical looping processes. A novel chemical looping scheme for selective oxidation of methanol has been reported, using silica-supported vanadium phosphorous oxide as the oxygen carrier.