Significant catalytic recovery of spent industrial DuPont catalysts by surface deposition of an amorphous vanadium-phosphorus oxide phase

► Under industrial reaction conditions DuPont-VPO catalyst was deactivated. ► A small amount of VPO phase (P/V = 0.86/1) was synthesized on its surface. ► Significant reactivation of DuPont-VPO catalyst was observed after VPO phase loading. ► Loading with VPO phase resulted in restoring more appropriate V5+/V4+ and P/V ratios.